[Sursound] RIR measuring, how to capture a higher order Ambisonic room responce?

[Bo-Erik Sandholm]

I want to measure the RIR of a medium size good listening room at least up
to second order Ambisonic RIR.

The IR result is to incorporate the responce and reflections of the
speakers and their positions.

I have a tetramic.

Can several measurements and rotation of the tetra mic between them be
combined to create the measurements that comes closer to a second order mic?

I know the basics of using Audacity, and a audio sweep and creating a IR
from this.



Bo-Erik Sandholm
Stockholm
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[Pierre Alexandre Tremblay]

If you use Max, try the very versatile HIRT.

2nd order with a tetramic is not possible as far as I am aware through… we have done (mega)multimic IRs (24 channels of inputs, of which a 1st order ambisonic) of 3 different spaces with our kit, and it was fun and productive to train the ear on difference of multichannel mic techniques (Hyunkook Lee has a cool setup and papers on them, and I was mostly interested in DPA LCR omni vs coincident vs MS)

We did many stage positions too. I can investigate if I can share the files if that interests anyone.

p


> On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com> wrote:
>
> I want to measure the RIR of a medium size good listening room at least up
> to second order Ambisonic RIR.
>
> The IR result is to incorporate the responce and reflections of the
> speakers and their positions.
>
> I have a tetramic.
>
> Can several measurements and rotation of the tetra mic between them be
> combined to create the measurements that comes closer to a second order mic?
>
> I know the basics of using Audacity, and a audio sweep and creating a IR
> from this.
>
>
>
> Bo-Erik Sandholm
> Stockholm
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20180423/ee496094/attachment.html>
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.

[Hyunkook Lee]

Indeed HIRT is the best IR capture package for Max. There is also HAART, which is a standalone Max application we developed using HIRT. This software is all in one box for multichannel IR capture (24 mics x 24 sources), acoustic parameter analysis and binauralisation. The analysis part is still under development, but the IR capture and binauralisation parts are fully working. You can download it here

http://eprints.hud.ac.uk/id/eprint/24579/

Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel mic array configurations from stereo to 9ch 3D using HAART. The library comes with a Max renderer where you can convolve dry sources or signals fed from DAW with the mic array IRs for simultaneous comparisons between techniques.

https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer

Best,
Hyunkook
=========================================
Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
Senior Lecturer in Music Technology
Leader of the Applied Psychoacoustics Laboratory (APL)
http://www.hud.ac.uk/apl
http://www.hyunkooklee.com
Phone: [phone]
Email: ***@hud.ac.uk
Office: CE 2 /14a
School of Computing and Engineering
University of Huddersfield
Huddersfield
HD1 3DH
United Kingdom

________________________________________
From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre Alexandre Tremblay [***@gmail.com]
Sent: 23 April 2018 09:29
To: Surround Sound discussion group
Subject: Re: [Sursound] RIR measuring, how to capture a higher order Ambisonic room responce?

If you use Max, try the very versatile HIRT.

2nd order with a tetramic is not possible as far as I am aware through… we have done (mega)multimic IRs (24 channels of inputs, of which a 1st order ambisonic) of 3 different spaces with our kit, and it was fun and productive to train the ear on difference of multichannel mic techniques (Hyunkook Lee has a cool setup and papers on them, and I was mostly interested in DPA LCR omni vs coincident vs MS)

We did many stage positions too. I can investigate if I can share the files if that interests anyone.

p


> On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com> wrote:
>
> I want to measure the RIR of a medium size good listening room at least up
> to second order Ambisonic RIR.
>
> The IR result is to incorporate the responce and reflections of the
> speakers and their positions.
>
> I have a tetramic.
>
> Can several measurements and rotation of the tetra mic between them be
> combined to create the measurements that comes closer to a second order mic?
>
> I know the basics of using Audacity, and a audio sweep and creating a IR
> from this.
>
>
>
> Bo-Erik Sandholm
> Stockholm
> -------------- next part --------------
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> URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20180423/ee496094/attachment.html>
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.

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This transmission is confidential and may be legally privileged. If you receive it in error, please notify us immediately by e-mail and remove it from your system. If the content of this e-mail does not relate to the business of the University of Huddersfield, then we do not endorse it and will accept no liability.

[Bo-Erik Sandholm]

Have never used Max, I need just 2, but probably 4 sound source positions
and one listening position.
But the listening position should have full spherical ambisonic soundfield.
But the result should be ambisonic IR's for these 4 sources.

The question is could upsampling be used ?

BR Bo-Erik



2018-04-23 10:47 GMT+02:00 Hyunkook Lee <***@hud.ac.uk>:

> Indeed HIRT is the best IR capture package for Max. There is also HAART,
> which is a standalone Max application we developed using HIRT. This
> software is all in one box for multichannel IR capture (24 mics x 24
> sources), acoustic parameter analysis and binauralisation. The analysis
> part is still under development, but the IR capture and binauralisation
> parts are fully working. You can download it here
>
> http://eprints.hud.ac.uk/id/eprint/24579/
>
> Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel mic
> array configurations from stereo to 9ch 3D using HAART. The library comes
> with a Max renderer where you can convolve dry sources or signals fed from
> DAW with the mic array IRs for simultaneous comparisons between techniques.
>
> https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer
>
> Best,
> Hyunkook
> =========================================
> Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
> Senior Lecturer in Music Technology
> Leader of the Applied Psychoacoustics Laboratory (APL)
> http://www.hud.ac.uk/apl
> http://www.hyunkooklee.com
> Phone: [phone]
> Email: ***@hud.ac.uk
> Office: CE 2 /14a
> School of Computing and Engineering
> University of Huddersfield
> Huddersfield
> HD1 3DH
> United Kingdom
>
> ________________________________________
> From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre
> Alexandre Tremblay [***@gmail.com]
> Sent: 23 April 2018 09:29
> To: Surround Sound discussion group
> Subject: Re: [Sursound] RIR measuring, how to capture a higher order
> Ambisonic room responce?
>
> If you use Max, try the very versatile HIRT.
>
> 2nd order with a tetramic is not possible as far as I am aware through… we
> have done (mega)multimic IRs (24 channels of inputs, of which a 1st order
> ambisonic) of 3 different spaces with our kit, and it was fun and
> productive to train the ear on difference of multichannel mic techniques
> (Hyunkook Lee has a cool setup and papers on them, and I was mostly
> interested in DPA LCR omni vs coincident vs MS)
>
> We did many stage positions too. I can investigate if I can share the
> files if that interests anyone.
>
> p
>
>
> > On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com> wrote:
> >
> > I want to measure the RIR of a medium size good listening room at least
> up
> > to second order Ambisonic RIR.
> >
> > The IR result is to incorporate the responce and reflections of the
> > speakers and their positions.
> >
> > I have a tetramic.
> >
> > Can several measurements and rotation of the tetra mic between them be
> > combined to create the measurements that comes closer to a second order
> mic?
> >
> > I know the basics of using Audacity, and a audio sweep and creating a IR
> > from this.
> >
> >
> >
> > Bo-Erik Sandholm
> > Stockholm
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL: <https://mail.music.vt.edu/mailman/private/sursound/
> attachments/20180423/ee496094/attachment.html>
> > _______________________________________________
> > Sursound mailing list
> > ***@music.vt.edu
> > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> edit account or options, view archives and so on.
>
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> edit account or options, view archives and so on.
> University of Huddersfield inspiring tomorrow's professionals.
> [http://marketing.hud.ac.uk/_HOSTED/EmailSig2014/EmailSigFooter.jpg]
>
> This transmission is confidential and may be legally privileged. If you
> receive it in error, please notify us immediately by e-mail and remove it
> from your system. If the content of this e-mail does not relate to the
> business of the University of Huddersfield, then we do not endorse it and
> will accept no liability.
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> edit account or options, view archives and so on.
>
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[jack reynolds]

The new coresound octomic is based on two tetramics, with one rotated 45
degrees from the other, so if you could work out how the second order
B-format is extracted from the octomic array, you could potentially take an
A-format reponse with your tetramic, rotate the mic 45 degrees and capture
another, then process all eight channels?
Just a thought.

Jack

On 23 April 2018 at 11:51, Bo-Erik Sandholm <***@gmail.com> wrote:

> Have never used Max, I need just 2, but probably 4 sound source positions
> and one listening position.
> But the listening position should have full spherical ambisonic
> soundfield.
> But the result should be ambisonic IR's for these 4 sources.
>
> The question is could upsampling be used ?
>
> BR Bo-Erik
>
>
>
> 2018-04-23 10:47 GMT+02:00 Hyunkook Lee <***@hud.ac.uk>:
>
> > Indeed HIRT is the best IR capture package for Max. There is also HAART,
> > which is a standalone Max application we developed using HIRT. This
> > software is all in one box for multichannel IR capture (24 mics x 24
> > sources), acoustic parameter analysis and binauralisation. The analysis
> > part is still under development, but the IR capture and binauralisation
> > parts are fully working. You can download it here
> >
> > http://eprints.hud.ac.uk/id/eprint/24579/
> >
> > Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel
> mic
> > array configurations from stereo to 9ch 3D using HAART. The library comes
> > with a Max renderer where you can convolve dry sources or signals fed
> from
> > DAW with the mic array IRs for simultaneous comparisons between
> techniques.
> >
> > https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer
> >
> > Best,
> > Hyunkook
> > =========================================
> > Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
> > Senior Lecturer in Music Technology
> > Leader of the Applied Psychoacoustics Laboratory (APL)
> > http://www.hud.ac.uk/apl
> > http://www.hyunkooklee.com
> > Phone: [phone]
> > Email: ***@hud.ac.uk
> > Office: CE 2 /14a
> > School of Computing and Engineering
> > University of Huddersfield
> > Huddersfield
> > HD1 3DH
> > United Kingdom
> >
> > ________________________________________
> > From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre
> > Alexandre Tremblay [***@gmail.com]
> > Sent: 23 April 2018 09:29
> > To: Surround Sound discussion group
> > Subject: Re: [Sursound] RIR measuring, how to capture a higher order
> > Ambisonic room responce?
> >
> > If you use Max, try the very versatile HIRT.
> >
> > 2nd order with a tetramic is not possible as far as I am aware through…
> we
> > have done (mega)multimic IRs (24 channels of inputs, of which a 1st order
> > ambisonic) of 3 different spaces with our kit, and it was fun and
> > productive to train the ear on difference of multichannel mic techniques
> > (Hyunkook Lee has a cool setup and papers on them, and I was mostly
> > interested in DPA LCR omni vs coincident vs MS)
> >
> > We did many stage positions too. I can investigate if I can share the
> > files if that interests anyone.
> >
> > p
> >
> >
> > > On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com>
> wrote:
> > >
> > > I want to measure the RIR of a medium size good listening room at least
> > up
> > > to second order Ambisonic RIR.
> > >
> > > The IR result is to incorporate the responce and reflections of the
> > > speakers and their positions.
> > >
> > > I have a tetramic.
> > >
> > > Can several measurements and rotation of the tetra mic between them be
> > > combined to create the measurements that comes closer to a second order
> > mic?
> > >
> > > I know the basics of using Audacity, and a audio sweep and creating a
> IR
> > > from this.
> > >
> > >
> > >
> > > Bo-Erik Sandholm
> > > Stockholm
> > > -------------- next part --------------
> > > An HTML attachment was scrubbed...
> > > URL: <https://mail.music.vt.edu/mailman/private/sursound/
> > attachments/20180423/ee496094/attachment.html>
> > > _______________________________________________
> > > Sursound mailing list
> > > ***@music.vt.edu
> > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe
> here,
> > edit account or options, view archives and so on.
> >
> > _______________________________________________
> > Sursound mailing list
> > ***@music.vt.edu
> > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> > edit account or options, view archives and so on.
> > University of Huddersfield inspiring tomorrow's professionals.
> > [http://marketing.hud.ac.uk/_HOSTED/EmailSig2014/EmailSigFooter.jpg]
> >
> > This transmission is confidential and may be legally privileged. If you
> > receive it in error, please notify us immediately by e-mail and remove it
> > from your system. If the content of this e-mail does not relate to the
> > business of the University of Huddersfield, then we do not endorse it and
> > will accept no liability.
> > _______________________________________________
> > Sursound mailing list
> > ***@music.vt.edu
> > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> > edit account or options, view archives and so on.
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
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> _______________________________________________
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> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> edit account or options, view archives and so on.
>



--

07889727365

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Haggerston
London
E2 8FR


www.facebook.com/reynoldsmicrophones

www.sohovr.co.uk
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[jack reynolds]

or yes, take a first order B-Format IR and upsample using Harpex is another
possibility.

J

On 23 April 2018 at 12:24, jack reynolds <***@gmail.com> wrote:

> The new coresound octomic is based on two tetramics, with one rotated 45
> degrees from the other, so if you could work out how the second order
> B-format is extracted from the octomic array, you could potentially take an
> A-format reponse with your tetramic, rotate the mic 45 degrees and capture
> another, then process all eight channels?
> Just a thought.
>
> Jack
>
> On 23 April 2018 at 11:51, Bo-Erik Sandholm <***@gmail.com> wrote:
>
>> Have never used Max, I need just 2, but probably 4 sound source positions
>> and one listening position.
>> But the listening position should have full spherical ambisonic
>> soundfield.
>> But the result should be ambisonic IR's for these 4 sources.
>>
>> The question is could upsampling be used ?
>>
>> BR Bo-Erik
>>
>>
>>
>> 2018-04-23 10:47 GMT+02:00 Hyunkook Lee <***@hud.ac.uk>:
>>
>> > Indeed HIRT is the best IR capture package for Max. There is also
>> HAART,
>> > which is a standalone Max application we developed using HIRT. This
>> > software is all in one box for multichannel IR capture (24 mics x 24
>> > sources), acoustic parameter analysis and binauralisation. The analysis
>> > part is still under development, but the IR capture and binauralisation
>> > parts are fully working. You can download it here
>> >
>> > http://eprints.hud.ac.uk/id/eprint/24579/
>> >
>> > Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel
>> mic
>> > array configurations from stereo to 9ch 3D using HAART. The library
>> comes
>> > with a Max renderer where you can convolve dry sources or signals fed
>> from
>> > DAW with the mic array IRs for simultaneous comparisons between
>> techniques.
>> >
>> > https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer
>> >
>> > Best,
>> > Hyunkook
>> > =========================================
>> > Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
>> > Senior Lecturer in Music Technology
>> > Leader of the Applied Psychoacoustics Laboratory (APL)
>> > http://www.hud.ac.uk/apl
>> > http://www.hyunkooklee.com
>> > Phone: [phone]
>> > Email: ***@hud.ac.uk
>> > Office: CE 2 /14a
>> > School of Computing and Engineering
>> > University of Huddersfield
>> > Huddersfield
>> > HD1 3DH
>> > United Kingdom
>> >
>> > ________________________________________
>> > From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre
>> > Alexandre Tremblay [***@gmail.com]
>> > Sent: 23 April 2018 09:29
>> > To: Surround Sound discussion group
>> > Subject: Re: [Sursound] RIR measuring, how to capture a higher order
>> > Ambisonic room responce?
>> >
>> > If you use Max, try the very versatile HIRT.
>> >
>> > 2nd order with a tetramic is not possible as far as I am aware through…
>> we
>> > have done (mega)multimic IRs (24 channels of inputs, of which a 1st
>> order
>> > ambisonic) of 3 different spaces with our kit, and it was fun and
>> > productive to train the ear on difference of multichannel mic techniques
>> > (Hyunkook Lee has a cool setup and papers on them, and I was mostly
>> > interested in DPA LCR omni vs coincident vs MS)
>> >
>> > We did many stage positions too. I can investigate if I can share the
>> > files if that interests anyone.
>> >
>> > p
>> >
>> >
>> > > On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com>
>> wrote:
>> > >
>> > > I want to measure the RIR of a medium size good listening room at
>> least
>> > up
>> > > to second order Ambisonic RIR.
>> > >
>> > > The IR result is to incorporate the responce and reflections of the
>> > > speakers and their positions.
>> > >
>> > > I have a tetramic.
>> > >
>> > > Can several measurements and rotation of the tetra mic between them be
>> > > combined to create the measurements that comes closer to a second
>> order
>> > mic?
>> > >
>> > > I know the basics of using Audacity, and a audio sweep and creating a
>> IR
>> > > from this.
>> > >
>> > >
>> > >
>> > > Bo-Erik Sandholm
>> > > Stockholm
>> > > -------------- next part --------------
>> > > An HTML attachment was scrubbed...
>> > > URL: <https://mail.music.vt.edu/mailman/private/sursound/
>> > attachments/20180423/ee496094/attachment.html>
>> > > _______________________________________________
>> > > Sursound mailing list
>> > > ***@music.vt.edu
>> > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe
>> here,
>> > edit account or options, view archives and so on.
>> >
>> > _______________________________________________
>> > Sursound mailing list
>> > ***@music.vt.edu
>> > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>> > edit account or options, view archives and so on.
>> > University of Huddersfield inspiring tomorrow's professionals.
>> > [http://marketing.hud.ac.uk/_HOSTED/EmailSig2014/EmailSigFooter.jpg]
>> >
>> > This transmission is confidential and may be legally privileged. If you
>> > receive it in error, please notify us immediately by e-mail and remove
>> it
>> > from your system. If the content of this e-mail does not relate to the
>> > business of the University of Huddersfield, then we do not endorse it
>> and
>> > will accept no liability.
>> > _______________________________________________
>> > Sursound mailing list
>> > ***@music.vt.edu
>> > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>> > edit account or options, view archives and so on.
>> >
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL: <https://mail.music.vt.edu/mailman/private/sursound/attachme
>> nts/20180423/3de17520/attachment.html>
>> _______________________________________________
>> Sursound mailing list
>> ***@music.vt.edu
>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>> edit account or options, view archives and so on.
>>
>
>
>
> --
>
> 07889727365
>
> 02036861372
>
> 3 Swimmers Lane
> Haggerston
> London
> E2 8FR
>
>
> www.facebook.com/reynoldsmicrophones
>
> www.sohovr.co.uk
>
>
>


--

07889727365

02036861372

3 Swimmers Lane
Haggerston
London
E2 8FR


www.facebook.com/reynoldsmicrophones

www.sohovr.co.uk
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[Politis Archontis]

Hi Bo-Erik,

if you use Matlab or Octave, you could also try the SDM method to upsample from first-order RIRs to 2nd, 3rd, or any order you want basically. SDM stands for the Spatial Decomposition Method from my colleague Sakari Tervo, which has been used quite a lot for auralization and visualization of spatial room IRs. You can find the toolbox available online.

HARPEX could potentially do it too, but since it is made for reproduction/playback and most likely block processing, I don’t know if it would cope well with the fine temporal structure of the RIR.

Regards,
Archontis Politis



On 23 Apr 2018, at 14:25, jack reynolds <***@gmail.com<mailto:***@gmail.com>> wrote:

or yes, take a first order B-Format IR and upsample using Harpex is another
possibility.

J

On 23 April 2018 at 12:24, jack reynolds <***@gmail.com<mailto:***@gmail.com>> wrote:

The new coresound octomic is based on two tetramics, with one rotated 45
degrees from the other, so if you could work out how the second order
B-format is extracted from the octomic array, you could potentially take an
A-format reponse with your tetramic, rotate the mic 45 degrees and capture
another, then process all eight channels?
Just a thought.

Jack

On 23 April 2018 at 11:51, Bo-Erik Sandholm <***@gmail.com<mailto:***@gmail.com>> wrote:

Have never used Max, I need just 2, but probably 4 sound source positions
and one listening position.
But the listening position should have full spherical ambisonic
soundfield.
But the result should be ambisonic IR's for these 4 sources.

The question is could upsampling be used ?

BR Bo-Erik



2018-04-23 10:47 GMT+02:00 Hyunkook Lee <***@hud.ac.uk<mailto:***@hud.ac.uk>>:

Indeed HIRT is the best IR capture package for Max. There is also
HAART,
which is a standalone Max application we developed using HIRT. This
software is all in one box for multichannel IR capture (24 mics x 24
sources), acoustic parameter analysis and binauralisation. The analysis
part is still under development, but the IR capture and binauralisation
parts are fully working. You can download it here

http://eprints.hud.ac.uk/id/eprint/24579/

Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel
mic
array configurations from stereo to 9ch 3D using HAART. The library
comes
with a Max renderer where you can convolve dry sources or signals fed
from
DAW with the mic array IRs for simultaneous comparisons between
techniques.

https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer

Best,
Hyunkook
=========================================
Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
Senior Lecturer in Music Technology
Leader of the Applied Psychoacoustics Laboratory (APL)
http://www.hud.ac.uk/apl
http://www.hyunkooklee.com
Phone: [phone]
Email: ***@hud.ac.uk
Office: CE 2 /14a
School of Computing and Engineering
University of Huddersfield
Huddersfield
HD1 3DH
United Kingdom

________________________________________
From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre
Alexandre Tremblay [***@gmail.com]
Sent: 23 April 2018 09:29
To: Surround Sound discussion group
Subject: Re: [Sursound] RIR measuring, how to capture a higher order
Ambisonic room responce?

If you use Max, try the very versatile HIRT.

2nd order with a tetramic is not possible as far as I am aware through…
we
have done (mega)multimic IRs (24 channels of inputs, of which a 1st
order
ambisonic) of 3 different spaces with our kit, and it was fun and
productive to train the ear on difference of multichannel mic techniques
(Hyunkook Lee has a cool setup and papers on them, and I was mostly
interested in DPA LCR omni vs coincident vs MS)

We did many stage positions too. I can investigate if I can share the
files if that interests anyone.

p


On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com<mailto:***@gmail.com>>
wrote:

I want to measure the RIR of a medium size good listening room at
least
up
to second order Ambisonic RIR.

The IR result is to incorporate the responce and reflections of the
speakers and their positions.

I have a tetramic.

Can several measurements and rotation of the tetra mic between them be
combined to create the measurements that comes closer to a second
order
mic?

I know the basics of using Audacity, and a audio sweep and creating a
IR
from this.



Bo-Erik Sandholm
Stockholm
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02036861372

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[Fernando Lopez-Lezcano]

On 04/23/2018 04:24 AM, jack reynolds wrote:
> The new coresound octomic is based on two tetramics, with one rotated 45
> degrees from the other,

Hmm, does not look like that to me. If you, for example, take any two
opposite capsules in the upper ring as part of one tetrahedral
microphone, there are no capsules in the lower ring that would match the
lower half of that microphone (they are rotated 45 degrees from where
they should be).

-- Fernando

>so if you could work out how the second order
> B-format is extracted from the octomic array, you could potentially take an
> A-format reponse with your tetramic, rotate the mic 45 degrees and capture
> another, then process all eight channels?
> Just a thought.
>
> Jack
>
> On 23 April 2018 at 11:51, Bo-Erik Sandholm <***@gmail.com> wrote:
>
>> Have never used Max, I need just 2, but probably 4 sound source positions
>> and one listening position.
>> But the listening position should have full spherical ambisonic
>> soundfield.
>> But the result should be ambisonic IR's for these 4 sources.
>>
>> The question is could upsampling be used ?
>>
>> BR Bo-Erik
>>
>>
>>
>> 2018-04-23 10:47 GMT+02:00 Hyunkook Lee <***@hud.ac.uk>:
>>
>>> Indeed HIRT is the best IR capture package for Max. There is also HAART,
>>> which is a standalone Max application we developed using HIRT. This
>>> software is all in one box for multichannel IR capture (24 mics x 24
>>> sources), acoustic parameter analysis and binauralisation. The analysis
>>> part is still under development, but the IR capture and binauralisation
>>> parts are fully working. You can download it here
>>>
>>> http://eprints.hud.ac.uk/id/eprint/24579/
>>>
>>> Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel
>> mic
>>> array configurations from stereo to 9ch 3D using HAART. The library comes
>>> with a Max renderer where you can convolve dry sources or signals fed
>> from
>>> DAW with the mic array IRs for simultaneous comparisons between
>> techniques.
>>>
>>> https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer
>>>
>>> Best,
>>> Hyunkook
>>> =========================================
>>> Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
>>> Senior Lecturer in Music Technology
>>> Leader of the Applied Psychoacoustics Laboratory (APL)
>>> http://www.hud.ac.uk/apl
>>> http://www.hyunkooklee.com
>>> Phone: [phone]
>>> Email: ***@hud.ac.uk
>>> Office: CE 2 /14a
>>> School of Computing and Engineering
>>> University of Huddersfield
>>> Huddersfield
>>> HD1 3DH
>>> United Kingdom
>>>
>>> ________________________________________
>>> From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre
>>> Alexandre Tremblay [***@gmail.com]
>>> Sent: 23 April 2018 09:29
>>> To: Surround Sound discussion group
>>> Subject: Re: [Sursound] RIR measuring, how to capture a higher order
>>> Ambisonic room responce?
>>>
>>> If you use Max, try the very versatile HIRT.
>>>
>>> 2nd order with a tetramic is not possible as far as I am aware through…
>> we
>>> have done (mega)multimic IRs (24 channels of inputs, of which a 1st order
>>> ambisonic) of 3 different spaces with our kit, and it was fun and
>>> productive to train the ear on difference of multichannel mic techniques
>>> (Hyunkook Lee has a cool setup and papers on them, and I was mostly
>>> interested in DPA LCR omni vs coincident vs MS)
>>>
>>> We did many stage positions too. I can investigate if I can share the
>>> files if that interests anyone.
>>>
>>> p
>>>
>>>
>>>> On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com>
>> wrote:
>>>>
>>>> I want to measure the RIR of a medium size good listening room at least
>>> up
>>>> to second order Ambisonic RIR.
>>>>
>>>> The IR result is to incorporate the responce and reflections of the
>>>> speakers and their positions.
>>>>
>>>> I have a tetramic.
>>>>
>>>> Can several measurements and rotation of the tetra mic between them be
>>>> combined to create the measurements that comes closer to a second order
>>> mic?
>>>>
>>>> I know the basics of using Audacity, and a audio sweep and creating a
>> IR
>>>> from this.
>>>>
>>>>
>>>>
>>>> Bo-Erik Sandholm
>>>> Stockholm
>>>> -------------- next part --------------
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>>>> Sursound mailing list
>>>> ***@music.vt.edu
>>>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe
>> here,
>>> edit account or options, view archives and so on.
>>>
>>> _______________________________________________
>>> Sursound mailing list
>>> ***@music.vt.edu
>>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>>> edit account or options, view archives and so on.
>>> University of Huddersfield inspiring tomorrow's professionals.
>>> [http://marketing.hud.ac.uk/_HOSTED/EmailSig2014/EmailSigFooter.jpg]
>>>
>>> This transmission is confidential and may be legally privileged. If you
>>> receive it in error, please notify us immediately by e-mail and remove it
>>> from your system. If the content of this e-mail does not relate to the
>>> business of the University of Huddersfield, then we do not endorse it and
>>> will accept no liability.
>>> _______________________________________________
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>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>> edit account or options, view archives and so on.
>>
>
>
>

[Bo-Erik Sandholm]

As I see it to capture the signals for the upper layers of octomic with a
tetra mic you rotate the mic 90 degrees between the takes..
To capture the lower octomic elements layer go back to initial position,
then rotate Tetra mic 45 degrees and then 90 degrees for 2 recordings.

So 4 rotation direction to place the tetra mic elements in same positions
as the 8 Octomic capsules.

select the 8 A signals that corresponds to the octomic positions...

Then get our hands on the octomic software if possible and hopefully
translate the tetramic calibration file in to a octomic calibration file,
might be possible.

This has only a chance to work for IR measurements and if the rotation of
the tetramic is done without moving the center point of the mic head.

I hope this is possible, it should be a great new use of a tetramic to be
able with a little work to create second order room Impulse responses.

Bo-Erik

2018-04-23 19:10 GMT+02:00 Fernando Lopez-Lezcano <***@ccrma.stanford.edu>
:

> On 04/23/2018 04:24 AM, jack reynolds wrote:
>
>> The new coresound octomic is based on two tetramics, with one rotated 45
>> degrees from the other,
>>
>
> Hmm, does not look like that to me. If you, for example, take any two
> opposite capsules in the upper ring as part of one tetrahedral microphone,
> there are no capsules in the lower ring that would match the lower half of
> that microphone (they are rotated 45 degrees from where they should be).
>
> -- Fernando
>
>
> so if you could work out how the second order
>> B-format is extracted from the octomic array, you could potentially take
>> an
>> A-format reponse with your tetramic, rotate the mic 45 degrees and capture
>> another, then process all eight channels?
>> Just a thought.
>>
>> Jack
>>
>> On 23 April 2018 at 11:51, Bo-Erik Sandholm <***@gmail.com> wrote:
>>
>> Have never used Max, I need just 2, but probably 4 sound source positions
>>> and one listening position.
>>> But the listening position should have full spherical ambisonic
>>> soundfield.
>>> But the result should be ambisonic IR's for these 4 sources.
>>>
>>> The question is could upsampling be used ?
>>>
>>> BR Bo-Erik
>>>
>>>
>>>
>>> 2018-04-23 10:47 GMT+02:00 Hyunkook Lee <***@hud.ac.uk>:
>>>
>>> Indeed HIRT is the best IR capture package for Max. There is also HAART,
>>>> which is a standalone Max application we developed using HIRT. This
>>>> software is all in one box for multichannel IR capture (24 mics x 24
>>>> sources), acoustic parameter analysis and binauralisation. The analysis
>>>> part is still under development, but the IR capture and binauralisation
>>>> parts are fully working. You can download it here
>>>>
>>>> http://eprints.hud.ac.uk/id/eprint/24579/
>>>>
>>>> Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel
>>>>
>>> mic
>>>
>>>> array configurations from stereo to 9ch 3D using HAART. The library
>>>> comes
>>>> with a Max renderer where you can convolve dry sources or signals fed
>>>>
>>> from
>>>
>>>> DAW with the mic array IRs for simultaneous comparisons between
>>>>
>>> techniques.
>>>
>>>>
>>>> https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer
>>>>
>>>> Best,
>>>> Hyunkook
>>>> =========================================
>>>> Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
>>>> Senior Lecturer in Music Technology
>>>> Leader of the Applied Psychoacoustics Laboratory (APL)
>>>> http://www.hud.ac.uk/apl
>>>> http://www.hyunkooklee.com
>>>> Phone: [phone]
>>>> Email: ***@hud.ac.uk
>>>> Office: CE 2 /14a
>>>> School of Computing and Engineering
>>>> University of Huddersfield
>>>> Huddersfield
>>>> HD1 3DH
>>>> United Kingdom
>>>>
>>>> ________________________________________
>>>> From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre
>>>> Alexandre Tremblay [***@gmail.com]
>>>> Sent: 23 April 2018 09:29
>>>> To: Surround Sound discussion group
>>>> Subject: Re: [Sursound] RIR measuring, how to capture a higher order
>>>> Ambisonic room responce?
>>>>
>>>> If you use Max, try the very versatile HIRT.
>>>>
>>>> 2nd order with a tetramic is not possible as far as I am aware through…
>>>>
>>> we
>>>
>>>> have done (mega)multimic IRs (24 channels of inputs, of which a 1st
>>>> order
>>>> ambisonic) of 3 different spaces with our kit, and it was fun and
>>>> productive to train the ear on difference of multichannel mic techniques
>>>> (Hyunkook Lee has a cool setup and papers on them, and I was mostly
>>>> interested in DPA LCR omni vs coincident vs MS)
>>>>
>>>> We did many stage positions too. I can investigate if I can share the
>>>> files if that interests anyone.
>>>>
>>>> p
>>>>
>>>>
>>>> On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com>
>>>>>
>>>> wrote:
>>>
>>>>
>>>>> I want to measure the RIR of a medium size good listening room at least
>>>>>
>>>> up
>>>>
>>>>> to second order Ambisonic RIR.
>>>>>
>>>>> The IR result is to incorporate the responce and reflections of the
>>>>> speakers and their positions.
>>>>>
>>>>> I have a tetramic.
>>>>>
>>>>> Can several measurements and rotation of the tetra mic between them be
>>>>> combined to create the measurements that comes closer to a second order
>>>>>
>>>> mic?
>>>>
>>>>>
>>>>> I know the basics of using Audacity, and a audio sweep and creating a
>>>>>
>>>> IR
>>>
>>>> from this.
>>>>>
>>>>>
>>>>>
>>>>> Bo-Erik Sandholm
>>>>> Stockholm
>>>>> -------------- next part --------------
>>>>> An HTML attachment was scrubbed...
>>>>> URL: <https://mail.music.vt.edu/mailman/private/sursound/
>>>>>
>>>> attachments/20180423/ee496094/attachment.html>
>>>>
>>>>> _______________________________________________
>>>>> Sursound mailing list
>>>>> ***@music.vt.edu
>>>>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe
>>>>>
>>>> here,
>>>
>>>> edit account or options, view archives and so on.
>>>>
>>>> _______________________________________________
>>>> Sursound mailing list
>>>> ***@music.vt.edu
>>>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>>>> edit account or options, view archives and so on.
>>>> University of Huddersfield inspiring tomorrow's professionals.
>>>> [http://marketing.hud.ac.uk/_HOSTED/EmailSig2014/EmailSigFooter.jpg]
>>>>
>>>> This transmission is confidential and may be legally privileged. If you
>>>> receive it in error, please notify us immediately by e-mail and remove
>>>> it
>>>> from your system. If the content of this e-mail does not relate to the
>>>> business of the University of Huddersfield, then we do not endorse it
>>>> and
>>>> will accept no liability.
>>>> _______________________________________________
>>>> Sursound mailing list
>>>> ***@music.vt.edu
>>>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>>>> edit account or options, view archives and so on.
>>>>
>>>> -------------- next part --------------
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>>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
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>>>
>>>
>>
>>
>>
> _______________________________________________
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[Politis Archontis]

By the way one could actually use only one microphone, measure the RIR, rotate it to another point, repeat the measurement, and make a virtual array of hundreds or thousands of points for high-order RIR recording. This has actually been done and the work published by Boaz Rafaely and his research group.

Regards,
Archontis Politis



> On 23 Apr 2018, at 20:31, Bo-Erik Sandholm <***@gmail.com> wrote:
>
> As I see it to capture the signals for the upper layers of octomic with a
> tetra mic you rotate the mic 90 degrees between the takes..
> To capture the lower octomic elements layer go back to initial position,
> then rotate Tetra mic 45 degrees and then 90 degrees for 2 recordings.
>
> So 4 rotation direction to place the tetra mic elements in same positions
> as the 8 Octomic capsules.
>
> select the 8 A signals that corresponds to the octomic positions...
>
> Then get our hands on the octomic software if possible and hopefully
> translate the tetramic calibration file in to a octomic calibration file,
> might be possible.
>
> This has only a chance to work for IR measurements and if the rotation of
> the tetramic is done without moving the center point of the mic head.
>
> I hope this is possible, it should be a great new use of a tetramic to be
> able with a little work to create second order room Impulse responses.
>
> Bo-Erik
>
> 2018-04-23 19:10 GMT+02:00 Fernando Lopez-Lezcano <***@ccrma.stanford.edu>
> :

[Stefan Schreiber]

Stunning discussion here!

Now this is why it makes sense to keep your sursound membership...  😎

BR

Stefan

Citando Politis Archontis <***@aalto.fi>:

> By the way one could actually use only one microphone, measure the
> RIR, rotate it to another point, repeat the measurement, and make a
> virtual array of hundreds or thousands of points for high-order RIR
> recording. This has actually been done and the work published by
> Boaz Rafaely and his research group.
>
>
>
> Regards,
>
> Archontis Politis
>
>> On 23 Apr 2018, at 20:31, Bo-Erik Sandholm <***@gmail.com> wrote:
>>
>>
>>
>> As I see it to capture the signals for the upper layers of octomic with a
>>
>> tetra mic you rotate the mic 90 degrees between the takes..
>>
>> To capture the lower octomic  elements layer go back to initial position,
>>
>> then rotate Tetra mic 45 degrees and then 90 degrees for 2  recordings.
>>
>>
>>
>> So 4 rotation direction to place the tetra mic elements in same positions
>>
>> as the 8 Octomic capsules.
>>
>>
>>
>> select the 8 A signals that corresponds to the octomic positions...
>>
>>
>>
>> Then get our hands on the octomic software if possible and hopefully
>>
>> translate the tetramic calibration file in to a octomic calibration file,
>>
>> might be possible.
>>
>>
>>
>> This has only a chance to work for IR measurements and if the rotation of
>>
>> the tetramic is done without moving the center point of the mic head.
>>
>>
>>
>> I hope this is possible, it should be a great new use of a tetramic to be
>>
>> able with a little work to create second order room Impulse responses.
>>
>>
>>
>> Bo-Erik
>>
>>
>>
>> 2018-04-23 19:10 GMT+02:00 Fernando Lopez-Lezcano
>> <***@ccrma.stanford.edu>
>>
>> :
>
> _______________________________________________
>
> Sursound mailing list
>
>
> ***@music.vt.eduhttps://mail.music.vt.edu/mailman/listinfo/sursound[1]
> - unsubscribe here, edit account or options, view archives and so on.



Ligações:
---------
[1]
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[jack reynolds]

indeed. apologies, it is 90 degrees.

On 23 April 2018 at 18:31, Bo-Erik Sandholm <***@gmail.com> wrote:

> As I see it to capture the signals for the upper layers of octomic with a
> tetra mic you rotate the mic 90 degrees between the takes..
> To capture the lower octomic elements layer go back to initial position,
> then rotate Tetra mic 45 degrees and then 90 degrees for 2 recordings.
>
> So 4 rotation direction to place the tetra mic elements in same positions
> as the 8 Octomic capsules.
>
> select the 8 A signals that corresponds to the octomic positions...
>
> Then get our hands on the octomic software if possible and hopefully
> translate the tetramic calibration file in to a octomic calibration file,
> might be possible.
>
> This has only a chance to work for IR measurements and if the rotation of
> the tetramic is done without moving the center point of the mic head.
>
> I hope this is possible, it should be a great new use of a tetramic to be
> able with a little work to create second order room Impulse responses.
>
> Bo-Erik
>
> 2018-04-23 19:10 GMT+02:00 Fernando Lopez-Lezcano <
> ***@ccrma.stanford.edu>
> :
>
> > On 04/23/2018 04:24 AM, jack reynolds wrote:
> >
> >> The new coresound octomic is based on two tetramics, with one rotated 45
> >> degrees from the other,
> >>
> >
> > Hmm, does not look like that to me. If you, for example, take any two
> > opposite capsules in the upper ring as part of one tetrahedral
> microphone,
> > there are no capsules in the lower ring that would match the lower half
> of
> > that microphone (they are rotated 45 degrees from where they should be).
> >
> > -- Fernando
> >
> >
> > so if you could work out how the second order
> >> B-format is extracted from the octomic array, you could potentially take
> >> an
> >> A-format reponse with your tetramic, rotate the mic 45 degrees and
> capture
> >> another, then process all eight channels?
> >> Just a thought.
> >>
> >> Jack
> >>
> >> On 23 April 2018 at 11:51, Bo-Erik Sandholm <***@gmail.com>
> wrote:
> >>
> >> Have never used Max, I need just 2, but probably 4 sound source
> positions
> >>> and one listening position.
> >>> But the listening position should have full spherical ambisonic
> >>> soundfield.
> >>> But the result should be ambisonic IR's for these 4 sources.
> >>>
> >>> The question is could upsampling be used ?
> >>>
> >>> BR Bo-Erik
> >>>
> >>>
> >>>
> >>> 2018-04-23 10:47 GMT+02:00 Hyunkook Lee <***@hud.ac.uk>:
> >>>
> >>> Indeed HIRT is the best IR capture package for Max. There is also
> HAART,
> >>>> which is a standalone Max application we developed using HIRT. This
> >>>> software is all in one box for multichannel IR capture (24 mics x 24
> >>>> sources), acoustic parameter analysis and binauralisation. The
> analysis
> >>>> part is still under development, but the IR capture and
> binauralisation
> >>>> parts are fully working. You can download it here
> >>>>
> >>>> http://eprints.hud.ac.uk/id/eprint/24579/
> >>>>
> >>>> Also as Pierre mentioned, we captured over 2000 IRs of 39 multichannel
> >>>>
> >>> mic
> >>>
> >>>> array configurations from stereo to 9ch 3D using HAART. The library
> >>>> comes
> >>>> with a Max renderer where you can convolve dry sources or signals fed
> >>>>
> >>> from
> >>>
> >>>> DAW with the mic array IRs for simultaneous comparisons between
> >>>>
> >>> techniques.
> >>>
> >>>>
> >>>> https://github.com/APL-Huddersfield/MAIR-Library-and-Renderer
> >>>>
> >>>> Best,
> >>>> Hyunkook
> >>>> =========================================
> >>>> Dr Hyunkook Lee, BMus(Tonmeister), PhD, MAES, FHEA
> >>>> Senior Lecturer in Music Technology
> >>>> Leader of the Applied Psychoacoustics Laboratory (APL)
> >>>> http://www.hud.ac.uk/apl
> >>>> http://www.hyunkooklee.com
> >>>> Phone: [phone]
> >>>> Email: ***@hud.ac.uk
> >>>> Office: CE 2 /14a
> >>>> School of Computing and Engineering
> >>>> University of Huddersfield
> >>>> Huddersfield
> >>>> HD1 3DH
> >>>> United Kingdom
> >>>>
> >>>> ________________________________________
> >>>> From: Sursound [sursound-***@music.vt.edu] on behalf of Pierre
> >>>> Alexandre Tremblay [***@gmail.com]
> >>>> Sent: 23 April 2018 09:29
> >>>> To: Surround Sound discussion group
> >>>> Subject: Re: [Sursound] RIR measuring, how to capture a higher order
> >>>> Ambisonic room responce?
> >>>>
> >>>> If you use Max, try the very versatile HIRT.
> >>>>
> >>>> 2nd order with a tetramic is not possible as far as I am aware
> through…
> >>>>
> >>> we
> >>>
> >>>> have done (mega)multimic IRs (24 channels of inputs, of which a 1st
> >>>> order
> >>>> ambisonic) of 3 different spaces with our kit, and it was fun and
> >>>> productive to train the ear on difference of multichannel mic
> techniques
> >>>> (Hyunkook Lee has a cool setup and papers on them, and I was mostly
> >>>> interested in DPA LCR omni vs coincident vs MS)
> >>>>
> >>>> We did many stage positions too. I can investigate if I can share the
> >>>> files if that interests anyone.
> >>>>
> >>>> p
> >>>>
> >>>>
> >>>> On 23 Apr 2018, at 08:37, Bo-Erik Sandholm <***@gmail.com>
> >>>>>
> >>>> wrote:
> >>>
> >>>>
> >>>>> I want to measure the RIR of a medium size good listening room at
> least
> >>>>>
> >>>> up
> >>>>
> >>>>> to second order Ambisonic RIR.
> >>>>>
> >>>>> The IR result is to incorporate the responce and reflections of the
> >>>>> speakers and their positions.
> >>>>>
> >>>>> I have a tetramic.
> >>>>>
> >>>>> Can several measurements and rotation of the tetra mic between them
> be
> >>>>> combined to create the measurements that comes closer to a second
> order
> >>>>>
> >>>> mic?
> >>>>
> >>>>>
> >>>>> I know the basics of using Audacity, and a audio sweep and creating a
> >>>>>
> >>>> IR
> >>>
> >>>> from this.
> >>>>>
> >>>>>
> >>>>>
> >>>>> Bo-Erik Sandholm
> >>>>> Stockholm
> >>>>> -------------- next part --------------
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> >>>>
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> >>>>> Sursound mailing list
> >>>>> ***@music.vt.edu
> >>>>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe
> >>>>>
> >>>> here,
> >>>
> >>>> edit account or options, view archives and so on.
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--

07889727365

02036861372

3 Swimmers Lane
Haggerston
London
E2 8FR


www.facebook.com/reynoldsmicrophones

www.sohovr.co.uk
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[Fons Adriaensen]

On Mon, Apr 23, 2018 at 07:18:33PM +0100, jack reynolds wrote:

> indeed. apologies, it is 90 degrees.

Again no. To cover all the directions of the Octomic capsules
with a Tetramic you need 4 orientations of the Tetramic (and
you get another 8 directions as a bonus).

Ciao,

--
FA

[jack reynolds]

you are right fons.

it is an octohedron with the top four rotated 45 degrees.

but i would have thought two tetramic IRs at 90 rotated 90 degress from
each other would give you quite good coverage.

rotated 45, 90 and 135 would be even better! Plus another couple for up and
down?

J



On 23 April 2018 at 19:50, Fons Adriaensen <***@linuxaudio.org> wrote:

> On Mon, Apr 23, 2018 at 07:18:33PM +0100, jack reynolds wrote:
>
> > indeed. apologies, it is 90 degrees.
>
> Again no. To cover all the directions of the Octomic capsules
> with a Tetramic you need 4 orientations of the Tetramic (and
> you get another 8 directions as a bonus).
>
> Ciao,
>
> --
> FA
>
>
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> edit account or options, view archives and so on.
>



--

07889727365

02036861372

3 Swimmers Lane
Haggerston
London
E2 8FR


www.facebook.com/reynoldsmicrophones

www.sohovr.co.uk
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[Bo-Erik Sandholm]

I can do the 4 measurements with 45 degrees rotation of my tetramic, that
is not so difficult, the next step to create a second order ambisonic RIR
that is where I will fail :-).

I will need a more detailed step by step instruction to reach my goal :-).

Bo-Erik
Stockholm

On Mon, 23 Apr 2018 21:02 jack reynolds, <***@gmail.com> wrote:

> you are right fons.
>
> it is an octohedron with the top four rotated 45 degrees.
>
> but i would have thought two tetramic IRs at 90 rotated 90 degress from
> each other would give you quite good coverage.
>
> rotated 45, 90 and 135 would be even better! Plus another couple for up and
> down?
>
> J
>
>
>
> On 23 April 2018 at 19:50, Fons Adriaensen <***@linuxaudio.org> wrote:
>
> > On Mon, Apr 23, 2018 at 07:18:33PM +0100, jack reynolds wrote:
> >
> > > indeed. apologies, it is 90 degrees.
> >
> > Again no. To cover all the directions of the Octomic capsules
> > with a Tetramic you need 4 orientations of the Tetramic (and
> > you get another 8 directions as a bonus).
> >
> > Ciao,
> >
> > --
> > FA
> >
> >
> > _______________________________________________
> > Sursound mailing list
> > ***@music.vt.edu
> > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> > edit account or options, view archives and so on.
> >
>
>
>
> --
>
> 07889727365
>
> 02036861372
>
> 3 Swimmers Lane
> Haggerston
> London
> E2 8FR
>
>
> www.facebook.com/reynoldsmicrophones
>
> www.sohovr.co.uk
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://mail.music.vt.edu/mailman/private/sursound/attachments/20180423/f1a5166f/attachment.html
> >
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> edit account or options, view archives and so on.
>
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[Stefan Schreiber]

> I can do the 4 measurements with 45 degrees rotation of my tetramic, that
>
> is not so difficult,  the next step to create a second order ambisonic RIR
>
> that is where I will fail :-).

I believe you might need a quite high precision to be successful even
at the first step...

(A SF mike has narrowly spaced capsules, and needs calibration....The
mechanical precision you need to measure 2nd order with a FOA mike is
IMHO high.)

So the mathematical methods (based on FOA but improving the RIR
resolution, as suggested by Archontis) should be a better way to go
on... Especially since you could receive even higher
resolutions/orders, and in practice.

So the presented ideas to capture 2nd order RIRs via a 1st order mike
are brilliant, but are they practical?

And even if somebody could succeed in a very careful process: this
does not look to be a robust measurement method. ..

We always talk about the 1st reflections, in this case. Not reverb,
which is kind of statistical.

Of course you can try, but how much precision is rally needed? (Should
be clarified before...)

Stefan

——————————

Citando Bo-Erik Sandholm <***@gmail.com>:

> I can do the 4 measurements with 45 degrees rotation of my tetramic, that
>
> is not so difficult,  the next step to create a second order ambisonic RIR
>
> that is where I will fail :-).
>
>
>
> I will need a more detailed step by step instruction to reach my goal :-).
>
>
>
> Bo-Erik
>
> Stockholm
>
>
>
> On Mon, 23 Apr 2018 21:02 jack reynolds, <***@gmail.com> wrote:
>
>> you are right fons.
>>
>>
>>
>> it is an octohedron with the top four rotated 45 degrees.
>>
>>
>>
>> but i would have thought two tetramic IRs at 90 rotated 90 degress from
>>
>> each other would give you quite good coverage.
>>
>>
>>
>> rotated 45, 90 and 135 would be even better! Plus another couple for up and
>>
>> down?
>>
>>
>>
>> J
>>
>>
>>
>>
>>
>>
>>
>> On 23 April 2018 at 19:50, Fons Adriaensen <***@linuxaudio.org> wrote:
>>
>>
>>
>> On Mon, Apr 23, 2018 at 07:18:33PM +0100, jack reynolds wrote:
>>
>>
>>
>> > indeed. apologies, it is 90 degrees.
>>
>>
>>
>> Again no. To cover all the directions of the Octomic capsules
>>
>> with a Tetramic you need 4 orientations of the Tetramic (and
>>
>> you get another 8 directions as a bonus).
>>
>>
>>
>> Ciao,
>>
>>
>>
>> --
>>
>> FA
>>
>>
>>
>>
>>
>> _______________________________________________
>>
>> Sursound mailing list
>>
>> ***@music.vt.edu
>>
>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>>
>> edit account or options, view archives and so on.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> --
>>
>>
>>
>> 07889727365
>>
>>
>>
>> 02036861372
>>
>>
>>
>> 3 Swimmers Lane
>>
>> Haggerston
>>
>> London
>>
>> E2 8FR
>>
>>
>>
>>
>>
>> www.facebook.com/reynoldsmicrophones[1]
>>
>>
>>
>> www.sohovr.co.uk[2]
>>
>> -------------- next part --------------
>>
>> An HTML attachment was scrubbed...
>>
>> URL: <
>>
>>
>> https://mail.music.vt.edu/mailman/private/sursound/attachments/20180423/f1a5166f/attachment.html
>>
>>
>>
>> _______________________________________________
>>
>> Sursound mailing list
>>
>> ***@music.vt.edu
>>
>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>>
>> edit account or options, view archives and so on.
>
> -------------- next part --------------
>
> An HTML attachment was scrubbed...
>
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> Sursound mailing list
>
>
> ***@music.vt.eduhttps://mail.music.vt.edu/mailman/listinfo/sursound[3]
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[2] http://www.sohovr.co.uk
[3]
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[Fernando Lopez-Lezcano]

On 04/23/2018 12:42 PM, Stefan Schreiber wrote:
>> I can do the 4 measurements with 45 degrees rotation of my tetramic, that
>> is not so difficult, the next step to create a second order ambisonic
>> RIR
>>
>> that is where I will fail :-).

You would need to "calibrate" the created 8 capsule array. That is,
record impulse responses all around it in a big space or anechoic room
(enough to accurately sample the spherical harmonics you want), and then
derive an A to B converter from that. I have some preliminary code in my
SpHEAR project that tries to do that, but it is not a "push a button and
you are done" thing at all...

For Fons's code, and to do this the "right way"...
On 03/27/2018 01:18 PM, Fons Adriaensen wrote:
> ... you'll have to sell your soul :-)

:-P

> I believe you might need a quite high precision to be successful even at
> the first step...
>
> (A SF mike has narrowly spaced capsules, and needs calibration....The
> mechanical precision you need to measure 2nd order with a FOA mike is
> IMHO high.)

Based on my experience with the Octathingy's I have built I would agree,
you would need to be very precise (and repeatable).

In my case to get good calibration data I need to rotate the microphone
with no wobble and at different orientations (or if it is not _exactly_
perfect, try to get away with calibrating out the average delays to all
capsules).

BTW, I cannot move the speaker around which would probably be a better
solution because of space constraints... I can barely get 4.5mSecs of IR
data in the spaces I can use.

> So the mathematical methods (based on FOA but improving the RIR
> resolution, as suggested by Archontis) should be a better way to go
> on... Especially since you could receive even higher resolutions/orders,
> and in practice.
>
> So the presented ideas to capture 2nd order RIRs via a 1st order mike
> are brilliant, but are they practical?

Probably not practical IMHO.

> And even if somebody could succeed in a very careful process: this does
> not look to be a robust measurement method. ..
>
> We always talk about the 1st reflections, in this case. Not reverb,
> which is kind of statistical.
>
> Of course you can try, but how much precision is really needed? (Should
> be clarified before...)

I would have to go to my data to get some numbers... I definitely can
see effects at high frequencies when the data capture is not precise
(I'm in the process of trying to build a better measuring rig).

-- Fernando

[Eric Benjamin]

I did this rotation and calibration operation. Unfortunately the results were not great. When the array is rotated it has to overlay the previous position perfectly. There is also a tendency for the mic stand to wobble when it rotates. These results are shown in my AES paper on the second order microphone.

Eric Benjamin

From: Fernando Lopez-Lezcano
Sent: Monday, April 23, 2018 1:11 PM
To: Surround Sound discussion group
Subject: Re: [Sursound] RIR measuring,how to capture a higher order Ambisonic room responce?

On 04/23/2018 12:42 PM, Stefan Schreiber wrote:
>> I can do the 4 measurements with 45 degrees rotation of my tetramic, that
>> is not so difficult, the next step to create a second order ambisonic
>> RIR
>>
>> that is where I will fail :-).

You would need to "calibrate" the created 8 capsule array. That is,
record impulse responses all around it in a big space or anechoic room
(enough to accurately sample the spherical harmonics you want), and then
derive an A to B converter from that. I have some preliminary code in my
SpHEAR project that tries to do that, but it is not a "push a button and
you are done" thing at all...

For Fons's code, and to do this the "right way"...
On 03/27/2018 01:18 PM, Fons Adriaensen wrote:
> ... you'll have to sell your soul :-)

:-P

> I believe you might need a quite high precision to be successful even at
> the first step...
>
> (A SF mike has narrowly spaced capsules, and needs calibration....The
> mechanical precision you need to measure 2nd order with a FOA mike is
> IMHO high.)

Based on my experience with the Octathingy's I have built I would agree,
you would need to be very precise (and repeatable).

In my case to get good calibration data I need to rotate the microphone
with no wobble and at different orientations (or if it is not _exactly_
perfect, try to get away with calibrating out the average delays to all
capsules).

BTW, I cannot move the speaker around which would probably be a better
solution because of space constraints... I can barely get 4.5mSecs of IR
data in the spaces I can use.

> So the mathematical methods (based on FOA but improving the RIR
> resolution, as suggested by Archontis) should be a better way to go
> on... Especially since you could receive even higher resolutions/orders,
> and in practice.
>
> So the presented ideas to capture 2nd order RIRs via a 1st order mike
> are brilliant, but are they practical?

Probably not practical IMHO.

> And even if somebody could succeed in a very careful process: this does
> not look to be a robust measurement method. ..
>
> We always talk about the 1st reflections, in this case. Not reverb,
> which is kind of statistical.
>
> Of course you can try, but how much precision is really needed? (Should
> be clarified before...)

I would have to go to my data to get some numbers... I definitely can
see effects at high frequencies when the data capture is not precise
(I'm in the process of trying to build a better measuring rig).

-- Fernando

_______________________________________________
Sursound mailing list
***@music.vt.edu
https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.

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[Stefan Schreiber]

Citando Eric Benjamin <***@pacbell.net>:

> I did this rotation and calibration operation. Unfortunately the
> results were not great. When the array is rotated it has to overlay
> the previous position perfectly.  There is also a tendency for the
> mic stand to wobble when it rotates. These results are shown in my
> AES paper on the second order microphone.
>
>
>
> Eric Benjamin

As I suspected...

SF microphones are precision instruments! If even stand wobbling is an
issue I would say:

Forget about combining 4 separate IR measurements, and either

- use the available mathematical methods for FOA RIRs to increase the
resolution/order.

- use an Octomic (or alternatives) anyway. 

Thanks,

Stefan

> From: Fernando Lopez-Lezcano
>
> Sent: Monday, April 23, 2018 1:11 PM
>
> To: Surround Sound discussion group
>
> Subject: Re: [Sursound] RIR measuring,how to capture a higher order
> Ambisonic room responce?
>
>
>
> On 04/23/2018 12:42 PM, Stefan Schreiber wrote:
>
>>> I can do the 4 measurements with 45 degrees rotation of my tetramic, that
>>>
>>> is not so difficult,  the next step to create a second order ambisonic
>>>
>>> RIR
>>>
>>>
>>>
>>> that is where I will fail :-).
>
> You would need to "calibrate" the created 8 capsule array. That is,
>
> record impulse responses all around it in a big space or anechoic room
>
> (enough to accurately sample the spherical harmonics you want), and then
>
> derive an A to B converter from that. I have some preliminary code in my
>
> SpHEAR project that tries to do that, but it is not a "push a button and
>
> you are done" thing at all...
>
> _______________________________________________
>
> Sursound mailing list
>
>
> ***@music.vt.eduhttps://mail.music.vt.edu/mailman/listinfo/sursound[1]
> - unsubscribe here, edit account or options, view archives and so on.



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[Fons Adriaensen]

On Mon, Apr 23, 2018 at 01:10:56PM -0700, Fernando Lopez-Lezcano wrote:

> You would need to "calibrate" the created 8 capsule array. That is, record
> impulse responses all around it in a big space or anechoic room (enough to
> accurately sample the spherical harmonics you want), and then derive an A to
> B converter from that. I have some preliminary code in my SpHEAR project
> that tries to do that, but it is not a "push a button and you are done"
> thing at all...

Indeed not. To start with, how to do measurements that can actually be
trusted is something you learn only with experience. Rest assured that
the first five times you do this will produce near useless results,
and you will notice that only *after* most of the processing is done.
That is assuming that you have sanity checks in the procedure at all.
If not, the result can easily look OK but actually be totally wrong.

> In my case to get good calibration data I need to rotate the microphone with
> no wobble and at different orientations (or if it is not _exactly_ perfect,
> try to get away with calibrating out the average delays to all capsules).

There's practically no way to obtain precise positioning, unless you'd
use a robot to rotate the microphone, and that comes with its own sort
of potential problems (like reflections on the robot arm).
The only practical solution is to make the processing software detect
small position (and other) errors and compensate for them. This, plus
sanity checks, makes up at least three quarters of the code I use to
calibrate Tetra and Octomics. And those parts are also the most
difficult to get right and verified.

So unless you want to spend a few months full time to develop and test
all of this, I'd stronly advise to not even try it.

Returning to the original problem: it is perfectly possible to
obtain higher order room IRs from first order measurements.
The dominant early reflections tend to be separated in time, so
they can be isolated and recreated in higher order. For the
reverb tail only the statistics need to be correct. It's
not a trivial thing, but it can and has been done.

Ciao,

--
FA

[Fernando Lopez-Lezcano]

On 04/23/2018 03:19 PM, Fons Adriaensen wrote:
> On Mon, Apr 23, 2018 at 01:10:56PM -0700, Fernando Lopez-Lezcano wrote:
>> In my case to get good calibration data I need to rotate the microphone with
>> no wobble and at different orientations (or if it is not _exactly_ perfect,
>> try to get away with calibrating out the average delays to all capsules).
>
> There's practically no way to obtain precise positioning,

Yes, I get (measurable) wobble even after "calibrating" the position of
the array (I have a small XY table at the bottom of the rig to be able
to offset the center of the array with respect to the center of
rotation). No way to make this "perfect", just the stiffness of all
parts and play is enough to create small errors.

> unless you'd use a robot to rotate the microphone,

Funny you would say that, I have a robotic arm on order (I should have
gotten it a couple of weeks ago but some part was apparently on
back-order)...

>and that comes with its own sort
> of potential problems (like reflections on the robot arm).

Indeed, at this point I'm not sure it is going to be a solution, or just
another problem :-) A robot arm that is big enough to be "out of the
way" would be way too expensive. Very cheap ones are too small and don't
have enough carrying capacity and precision. Some are obviously too
"fat" and will be a pain in terms of reflections, or too short and not
enough reach. We'll see if what I'm getting is good enough...

At least it should make the task of doing many repeatable measurements
not so insane, at this point everything is manual (I am the robot).

Of course driving the robotic arm so that it positions the center of the
microphone at the right spot is probably not going to be easy either.
Again, physical interface, tolerances, play... Hmmm, jack-delay and arm,
feedback loop, hmmm[*]...

> The only practical solution is to make the processing software detect
> small position (and other) errors and compensate for them.

I reached the same conclusion, and that is what I'm doing now. So far it
looks like an improvement.

-- Fernando

[*] unstable system, the arm goes wild and destroys the microphone,
nothing left to measure!, bliss.....

[umashankar manthravadi]

I have been using a stepper motor (of the kind used in 3d printer ) driven by a low cost Arduino and motor control board. I 3d print a snug fitting fixture for the microphone with the motor shaft aligned to the array centre. It is low cost so I design a fitting for each mic I test, including the Brahma-in-Zoom. A small Arduino script rotates the stepper 25 steps each time I press a button (for 16 positions) and 50 steps (for 8 positions). I was worried about the stepper skipping with the weight of the microphone, but that is not happening, even with a five volt supply. I was ready with a thrust bearing between the motor housing and the microphone housing but it was not necessary. I plan to get rid of the switch and use a pulse on the right channel instead, though I generally do not like to automate things too much.



umashankar



Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10



________________________________
From: Sursound <sursound-***@music.vt.edu> on behalf of Fernando Lopez-Lezcano <***@ccrma.Stanford.EDU>
Sent: Tuesday, April 24, 2018 1:40:56 AM
To: Surround Sound discussion group
Subject: Re: [Sursound] RIR measuring, how to capture a higher order Ambisonic room responce?

On 04/23/2018 12:42 PM, Stefan Schreiber wrote:
>> I can do the 4 measurements with 45 degrees rotation of my tetramic, that
>> is not so difficult, the next step to create a second order ambisonic
>> RIR
>>
>> that is where I will fail :-).

You would need to "calibrate" the created 8 capsule array. That is,
record impulse responses all around it in a big space or anechoic room
(enough to accurately sample the spherical harmonics you want), and then
derive an A to B converter from that. I have some preliminary code in my
SpHEAR project that tries to do that, but it is not a "push a button and
you are done" thing at all...

For Fons's code, and to do this the "right way"...
On 03/27/2018 01:18 PM, Fons Adriaensen wrote:
> ... you'll have to sell your soul :-)

:-P

> I believe you might need a quite high precision to be successful even at
> the first step...
>
> (A SF mike has narrowly spaced capsules, and needs calibration....The
> mechanical precision you need to measure 2nd order with a FOA mike is
> IMHO high.)

Based on my experience with the Octathingy's I have built I would agree,
you would need to be very precise (and repeatable).

In my case to get good calibration data I need to rotate the microphone
with no wobble and at different orientations (or if it is not _exactly_
perfect, try to get away with calibrating out the average delays to all
capsules).

BTW, I cannot move the speaker around which would probably be a better
solution because of space constraints... I can barely get 4.5mSecs of IR
data in the spaces I can use.

> So the mathematical methods (based on FOA but improving the RIR
> resolution, as suggested by Archontis) should be a better way to go
> on... Especially since you could receive even higher resolutions/orders,
> and in practice.
>
> So the presented ideas to capture 2nd order RIRs via a 1st order mike
> are brilliant, but are they practical?

Probably not practical IMHO.

> And even if somebody could succeed in a very careful process: this does
> not look to be a robust measurement method. ..
>
> We always talk about the 1st reflections, in this case. Not reverb,
> which is kind of statistical.
>
> Of course you can try, but how much precision is really needed? (Should
> be clarified before...)

I would have to go to my data to get some numbers... I definitely can
see effects at high frequencies when the data capture is not precise
(I'm in the process of trying to build a better measuring rig).

-- Fernando

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Sursound mailing list
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[Bo-Erik Sandholm]

Thank you all, for your answers.
I received a lot of information.

I will start with FOA RIRs from my tetramic , it seems my ideas for
measuring higher orders are not realistic without a higher order microphone.

And FOA is probably good enough for my proof of concept.



Best Regards
Bo-Erik Sandholm
Stockholm

On Tue, 24 Apr 2018 03:59 umashankar manthravadi, <***@hotmail.com>
wrote:

> I have been using a stepper motor (of the kind used in 3d printer ) driven
> by a low cost Arduino and motor control board. I 3d print a snug fitting
> fixture for the microphone with the motor shaft aligned to the array
> centre. It is low cost so I design a fitting for each mic I test, including
> the Brahma-in-Zoom. A small Arduino script rotates the stepper 25 steps
> each time I press a button (for 16 positions) and 50 steps (for 8
> positions). I was worried about the stepper skipping with the weight of the
> microphone, but that is not happening, even with a five volt supply. I was
> ready with a thrust bearing between the motor housing and the microphone
> housing but it was not necessary. I plan to get rid of the switch and use a
> pulse on the right channel instead, though I generally do not like to
> automate things too much.
>
>
>
> umashankar
>
>
>
> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> ________________________________
> From: Sursound <sursound-***@music.vt.edu> on behalf of Fernando
> Lopez-Lezcano <***@ccrma.Stanford.EDU>
> Sent: Tuesday, April 24, 2018 1:40:56 AM
> To: Surround Sound discussion group
> Subject: Re: [Sursound] RIR measuring, how to capture a higher order
> Ambisonic room responce?
>
> On 04/23/2018 12:42 PM, Stefan Schreiber wrote:
> >> I can do the 4 measurements with 45 degrees rotation of my tetramic,
> that
> >> is not so difficult, the next step to create a second order ambisonic
> >> RIR
> >>
> >> that is where I will fail :-).
>
> You would need to "calibrate" the created 8 capsule array. That is,
> record impulse responses all around it in a big space or anechoic room
> (enough to accurately sample the spherical harmonics you want), and then
> derive an A to B converter from that. I have some preliminary code in my
> SpHEAR project that tries to do that, but it is not a "push a button and
> you are done" thing at all...
>
> For Fons's code, and to do this the "right way"...
> On 03/27/2018 01:18 PM, Fons Adriaensen wrote:
> > ... you'll have to sell your soul :-)
>
> :-P
>
> > I believe you might need a quite high precision to be successful even at
> > the first step...
> >
> > (A SF mike has narrowly spaced capsules, and needs calibration....The
> > mechanical precision you need to measure 2nd order with a FOA mike is
> > IMHO high.)
>
> Based on my experience with the Octathingy's I have built I would agree,
> you would need to be very precise (and repeatable).
>
> In my case to get good calibration data I need to rotate the microphone
> with no wobble and at different orientations (or if it is not _exactly_
> perfect, try to get away with calibrating out the average delays to all
> capsules).
>
> BTW, I cannot move the speaker around which would probably be a better
> solution because of space constraints... I can barely get 4.5mSecs of IR
> data in the spaces I can use.
>
> > So the mathematical methods (based on FOA but improving the RIR
> > resolution, as suggested by Archontis) should be a better way to go
> > on... Especially since you could receive even higher resolutions/orders,
> > and in practice.
> >
> > So the presented ideas to capture 2nd order RIRs via a 1st order mike
> > are brilliant, but are they practical?
>
> Probably not practical IMHO.
>
> > And even if somebody could succeed in a very careful process: this does
> > not look to be a robust measurement method. ..
> >
> > We always talk about the 1st reflections, in this case. Not reverb,
> > which is kind of statistical.
> >
> > Of course you can try, but how much precision is really needed? (Should
> > be clarified before...)
>
> I would have to go to my data to get some numbers... I definitely can
> see effects at high frequencies when the data capture is not precise
> (I'm in the process of trying to build a better measuring rig).
>
> -- Fernando
>
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
>
> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.music.vt.edu%2Fmailman%2Flistinfo%2Fsursound&data=02%7C01%7C%7Cd2d37994bf824a649cfd08d5a9565d6f%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636601110750131368&sdata=9yJTw53ccb0AvWlk1eg1qrtsvsUW7PeBngbvZ3w9Hck%3D&reserved=0
> - unsubscribe here, edit account or options, view archives and so on.
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[Dave Malham]

Excellent - this is exactly the method I was about to suggest - steppers,
related hardware and motor control boards have been driven down in price so
much by the 3-d printing/cnc/maker revolution that it makes almost no sense
to do anything else. I would use the esp8266 arduino compatible wifi module
which costs about the same as a decent cappuccino - I paid about 4 euros
for one at the end of last year - which has a reasonably powerful 16 bit
processor and is quite capable of acting as a web server, so I'm doing that
and controlling my steppers from a web based interface on my mobile or
laptop. Note, however, that I've confined it to just my home network for
security sake - don't want people using it to influence the elections :-)

Dave
PS Sorry once again I'm not currently doing this for audio - maybe one of
these days I'll get back to that.

On 24 April 2018 at 02:58, umashankar manthravadi <***@hotmail.com>
wrote:

> I have been using a stepper motor (of the kind used in 3d printer ) driven
> by a low cost Arduino and motor control board. I 3d print a snug fitting
> fixture for the microphone with the motor shaft aligned to the array
> centre. It is low cost so I design a fitting for each mic I test, including
> the Brahma-in-Zoom. A small Arduino script rotates the stepper 25 steps
> each time I press a button (for 16 positions) and 50 steps (for 8
> positions). I was worried about the stepper skipping with the weight of the
> microphone, but that is not happening, even with a five volt supply. I was
> ready with a thrust bearing between the motor housing and the microphone
> housing but it was not necessary. I plan to get rid of the switch and use a
> pulse on the right channel instead, though I generally do not like to
> automate things too much.
>
>
>
> umashankar
>
>
>
> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> ________________________________
> From: Sursound <sursound-***@music.vt.edu> on behalf of Fernando
> Lopez-Lezcano <***@ccrma.Stanford.EDU>
> Sent: Tuesday, April 24, 2018 1:40:56 AM
> To: Surround Sound discussion group
> Subject: Re: [Sursound] RIR measuring, how to capture a higher order
> Ambisonic room responce?
>
> On 04/23/2018 12:42 PM, Stefan Schreiber wrote:
> >> I can do the 4 measurements with 45 degrees rotation of my tetramic,
> that
> >> is not so difficult, the next step to create a second order ambisonic
> >> RIR
> >>
> >> that is where I will fail :-).
>
> You would need to "calibrate" the created 8 capsule array. That is,
> record impulse responses all around it in a big space or anechoic room
> (enough to accurately sample the spherical harmonics you want), and then
> derive an A to B converter from that. I have some preliminary code in my
> SpHEAR project that tries to do that, but it is not a "push a button and
> you are done" thing at all...
>
> For Fons's code, and to do this the "right way"...
> On 03/27/2018 01:18 PM, Fons Adriaensen wrote:
> > ... you'll have to sell your soul :-)
>
> :-P
>
> > I believe you might need a quite high precision to be successful even at
> > the first step...
> >
> > (A SF mike has narrowly spaced capsules, and needs calibration....The
> > mechanical precision you need to measure 2nd order with a FOA mike is
> > IMHO high.)
>
> Based on my experience with the Octathingy's I have built I would agree,
> you would need to be very precise (and repeatable).
>
> In my case to get good calibration data I need to rotate the microphone
> with no wobble and at different orientations (or if it is not _exactly_
> perfect, try to get away with calibrating out the average delays to all
> capsules).
>
> BTW, I cannot move the speaker around which would probably be a better
> solution because of space constraints... I can barely get 4.5mSecs of IR
> data in the spaces I can use.
>
> > So the mathematical methods (based on FOA but improving the RIR
> > resolution, as suggested by Archontis) should be a better way to go
> > on... Especially since you could receive even higher resolutions/orders,
> > and in practice.
> >
> > So the presented ideas to capture 2nd order RIRs via a 1st order mike
> > are brilliant, but are they practical?
>
> Probably not practical IMHO.
>
> > And even if somebody could succeed in a very careful process: this does
> > not look to be a robust measurement method. ..
> >
> > We always talk about the 1st reflections, in this case. Not reverb,
> > which is kind of statistical.
> >
> > Of course you can try, but how much precision is really needed? (Should
> > be clarified before...)
>
> I would have to go to my data to get some numbers... I definitely can
> see effects at high frequencies when the data capture is not precise
> (I'm in the process of trying to build a better measuring rig).
>
> -- Fernando
>
> _______________________________________________
> Sursound mailing list
> ***@music.vt.edu
> https://nam04.safelinks.protection.outlook.com/?url=
> https%3A%2F%2Fmail.music.vt.edu%2Fmailman%2Flistinfo%
> 2Fsursound&data=02%7C01%7C%7Cd2d37994bf824a649cfd08d5a9565d6f%
> 7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636601110750131368&sdata=
> 9yJTw53ccb0AvWlk1eg1qrtsvsUW7PeBngbvZ3w9Hck%3D&reserved=0 - unsubscribe
> here, edit account or options, view archives and so on.
> -------------- next part --------------
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> URL: <https://mail.music.vt.edu/mailman/private/sursound/
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> _______________________________________________
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> ***@music.vt.edu
> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
> edit account or options, view archives and so on.
>



--

As of 1st October 2012, I have retired from the University.

These are my own views and may or may not be shared by the University

Dave Malham
Honorary Fellow, Department of Music
The University of York
York YO10 5DD
UK

'Ambisonics - Component Imaging for Audio'
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[Marc Lavallée]

The ESP8266 can work as a wifi hotspot, so there's no need to connect it
to a network. That's how many new gadgets are working, and that's what
I'm doing now with a Raspberry Pi for a sound installation.  Instead of
some Arduino board, I would use a Raspberry Pi to also record the sweeps
(and even process them). What's missing the most is a well documented
method to calibrate a microphone; but according to experts it's so
difficult that even trying to think about it is a waste of time...

Marc


Le 2018-04-29 à 09:13 AM, Dave Malham a écrit :
> Excellent - this is exactly the method I was about to suggest - steppers,
> related hardware and motor control boards have been driven down in price so
> much by the 3-d printing/cnc/maker revolution that it makes almost no sense
> to do anything else. I would use the esp8266 arduino compatible wifi module
> which costs about the same as a decent cappuccino - I paid about 4 euros
> for one at the end of last year - which has a reasonably powerful 16 bit
> processor and is quite capable of acting as a web server, so I'm doing that
> and controlling my steppers from a web based interface on my mobile or
> laptop. Note, however, that I've confined it to just my home network for
> security sake - don't want people using it to influence the elections :-)
>
> Dave
> PS Sorry once again I'm not currently doing this for audio - maybe one of
> these days I'll get back to that.
>
> On 24 April 2018 at 02:58, umashankar manthravadi <***@hotmail.com>
> wrote:
>
>> I have been using a stepper motor (of the kind used in 3d printer ) driven
>> by a low cost Arduino and motor control board. I 3d print a snug fitting
>> fixture for the microphone with the motor shaft aligned to the array
>> centre. It is low cost so I design a fitting for each mic I test, including
>> the Brahma-in-Zoom. A small Arduino script rotates the stepper 25 steps
>> each time I press a button (for 16 positions) and 50 steps (for 8
>> positions). I was worried about the stepper skipping with the weight of the
>> microphone, but that is not happening, even with a five volt supply. I was
>> ready with a thrust bearing between the motor housing and the microphone
>> housing but it was not necessary. I plan to get rid of the switch and use a
>> pulse on the right channel instead, though I generally do not like to
>> automate things too much.
>>
>>
>>
>> umashankar
>>
>>
>>
>> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for
>> Windows 10
>>
>>
>>
>> ________________________________
>> From: Sursound <sursound-***@music.vt.edu> on behalf of Fernando
>> Lopez-Lezcano <***@ccrma.Stanford.EDU>
>> Sent: Tuesday, April 24, 2018 1:40:56 AM
>> To: Surround Sound discussion group
>> Subject: Re: [Sursound] RIR measuring, how to capture a higher order
>> Ambisonic room responce?
>>
>> On 04/23/2018 12:42 PM, Stefan Schreiber wrote:
>>>> I can do the 4 measurements with 45 degrees rotation of my tetramic,
>> that
>>>> is not so difficult, the next step to create a second order ambisonic
>>>> RIR
>>>>
>>>> that is where I will fail :-).
>> You would need to "calibrate" the created 8 capsule array. That is,
>> record impulse responses all around it in a big space or anechoic room
>> (enough to accurately sample the spherical harmonics you want), and then
>> derive an A to B converter from that. I have some preliminary code in my
>> SpHEAR project that tries to do that, but it is not a "push a button and
>> you are done" thing at all...
>>
>> For Fons's code, and to do this the "right way"...
>> On 03/27/2018 01:18 PM, Fons Adriaensen wrote:
>>> ... you'll have to sell your soul :-)
>> :-P
>>
>>> I believe you might need a quite high precision to be successful even at
>>> the first step...
>>>
>>> (A SF mike has narrowly spaced capsules, and needs calibration....The
>>> mechanical precision you need to measure 2nd order with a FOA mike is
>>> IMHO high.)
>> Based on my experience with the Octathingy's I have built I would agree,
>> you would need to be very precise (and repeatable).
>>
>> In my case to get good calibration data I need to rotate the microphone
>> with no wobble and at different orientations (or if it is not _exactly_
>> perfect, try to get away with calibrating out the average delays to all
>> capsules).
>>
>> BTW, I cannot move the speaker around which would probably be a better
>> solution because of space constraints... I can barely get 4.5mSecs of IR
>> data in the spaces I can use.
>>
>>> So the mathematical methods (based on FOA but improving the RIR
>>> resolution, as suggested by Archontis) should be a better way to go
>>> on... Especially since you could receive even higher resolutions/orders,
>>> and in practice.
>>>
>>> So the presented ideas to capture 2nd order RIRs via a 1st order mike
>>> are brilliant, but are they practical?
>> Probably not practical IMHO.
>>
>>> And even if somebody could succeed in a very careful process: this does
>>> not look to be a robust measurement method. ..
>>>
>>> We always talk about the 1st reflections, in this case. Not reverb,
>>> which is kind of statistical.
>>>
>>> Of course you can try, but how much precision is really needed? (Should
>>> be clarified before...)
>> I would have to go to my data to get some numbers... I definitely can
>> see effects at high frequencies when the data capture is not precise
>> (I'm in the process of trying to build a better measuring rig).
>>
>> -- Fernando
>>
>> _______________________________________________
>> Sursound mailing list
>> ***@music.vt.edu
>> https://nam04.safelinks.protection.outlook.com/?url=
>> https%3A%2F%2Fmail.music.vt.edu%2Fmailman%2Flistinfo%
>> 2Fsursound&data=02%7C01%7C%7Cd2d37994bf824a649cfd08d5a9565d6f%
>> 7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636601110750131368&sdata=
>> 9yJTw53ccb0AvWlk1eg1qrtsvsUW7PeBngbvZ3w9Hck%3D&reserved=0 - unsubscribe
>> here, edit account or options, view archives and so on.
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL: <https://mail.music.vt.edu/mailman/private/sursound/
>> attachments/20180424/5f8768e9/attachment.html>
>> _______________________________________________
>> Sursound mailing list
>> ***@music.vt.edu
>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here,
>> edit account or options, view archives and so on.
>>
>
>

[Peter P.]

Fernando,

I am sure you aware of the VariSphear robotic arm mic array that
Benjamin Bernschütz and collaborators built in 2010. I haven't found a
pic of it, but there are some articles (some in German only). Benjamin
might be on this list.

http://audiogroup.web.th-koeln.de/PUBLIKATIONEN/Bernschuetz_DAGA2010.pdf

https://s3.amazonaws.com/academia.edu.documents/40394369/SOFiA_-_Sound_Field_Analysis_Toolbox20151126-32622-k6bcza.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1525945973&Signature=qD%2FqTavFqjtvh91kf3hFwJXNkwk%3D&response-content-disposition=inline%3B%20filename%3DSOFiA_sound_field_analysis_toolbox.pdf

[Fernando Lopez-Lezcano]

On 05/07/2018 07:05 PM, Fernando Lopez-Lezcano wrote:
...
> So I bought a robotic arm. Len (from Core Sound) asked off-list about
> it, so I'm including some information here. I got the WidowXL from
> Trossen Robotics. Anything better (as far as I could find, not an
> expert!) would have driven the price up ...

Just a quick update (maybe will help someone else). Most of this I knew
beforehand...

The robotic arm is a bit on the short side to manipulate my microphones
so as to get measurements at high elevations with respect to the
horizontal plane (ie: can't tilt it enough without changing the location
of the center of the array - or, with a different initial pose I can get
high elevations for one of the hemispheres but not for the other).
Shorter microphones should not have this problem. And the wrist servo
has only 300 degrees of rotation which makes it not so useful to rotate
the microphone for measurements.

So I modified it. I removed the gripper as I do not need it (which
shortened the wrist which means I can get better elevation coverage) and
replaced the wrist rotation servo with another one that has 360 degrees
of rotation (so I can use it to rotate the microphone for measurements -
this required me to design and 3d print a connection block). And
modified the software that controls the arm to take these changes into
account.

Looks more promising now...

Having played with it for a bit I know now it would not be out of the
question to design a more suitable arm with the same type of servos and
control board, it is a very flexible system. I could even lengthen the
arm segments of the one I have, but enough modding for now... :-)

-- Fernando

[Stefan Schreiber]

But Bo-Erik already wrote this...

So do we agree on 4 orientations? (Unless you just buy an Octomic, of
course...)

Best,

Stefan

———————————-

Citando Fons Adriaensen <***@linuxaudio.org>:

> On Mon, Apr 23, 2018 at 07:18:33PM +0100, jack reynolds wrote:
>
>> indeed. apologies, it is 90 degrees.
>
> Again no. To cover all the directions of the Octomic capsules
>
> with a Tetramic you need 4 orientations of the Tetramic (and
>
> you get another 8 directions as a bonus).
>
>
>
> Ciao,
>
>
>
> --
>
> FA
>
>
>
>
>
> _______________________________________________
>
> Sursound mailing list
>
>
> ***@music.vt.eduhttps://mail.music.vt.edu/mailman/listinfo/sursound[1]
> - unsubscribe here, edit account or options, view archives and so on.



Ligações:
---------
[1]
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[Fons Adriaensen]

On Mon, Apr 23, 2018 at 12:24:47PM +0100, jack reynolds wrote:

> The new coresound octomic is based on two tetramics, with one rotated 45
> degrees from the other

This is simply not true.

Ciao,

--
FA

[Dave Hunt]

Hi,

As far as I know you cannot simply obtain 2nd order channels from two sets of 1st order channels. A look at a visual representation of the spherical harmonics indicates that this is far from trivial.

https://brilliant.org/wiki/spherical-harmonics/

The SDM suggested by Archiontis, or Harpex may well use fairly complex mathematics to approximate a reasonable up-sample.

Ciao,

Dave Hunt


On 23 Apr 2018, at 17:00, sursound-***@music.vt.edu wrote:

> From: Politis Archontis <***@aalto.fi>
> Subject: Re: [Sursound] RIR measuring, how to capture a higher order Ambisonic room responce?
> Date: 23 April 2018 12:36:45 BST
> To: Surround Sound discussion group <***@music.vt.edu>
>
>
> Hi Bo-Erik,
>
> if you use Matlab or Octave, you could also try the SDM method to upsample from first-order RIRs to 2nd, 3rd, or any order you want basically. SDM stands for the Spatial Decomposition Method from my colleague Sakari Tervo, which has been used quite a lot for auralization and visualization of spatial room IRs. You can find the toolbox available online.
>
> HARPEX could potentially do it too, but since it is made for reproduction/playback and most likely block processing, I don’t know if it would cope well with the fine temporal structure of the RIR.
>
> Regards,
> Archontis Politis