Discussion:
[Sursound] What is Super Stereo?
Oliver Thuns
2008-09-25 12:55:46 UTC
Permalink
Hello,

Super Stereo is mentioned on several Ambisonics web pages, but I
couldn't find anything specific. I'm not looking for an explanation of
UHJ, which is sometimes used synonymously with Super Stereo, I'm
looking for some documentation on how Super Stereo is implemented in
the classic decoders.

Oli
Richard Elen
2008-09-25 14:21:37 UTC
Permalink
"Super Stereo" generally refers to the ability in several Ambisonic
decoders to use subsets of Ambisonic technology to extend the stable
stage width of stereophonic source material. In most cases a stereo
width control is provided which can be used to increase (or decrease)
the width of the soundstage. This is by no means synonymous with UHJ
although some of the UHJ decoder capability may be employed in realising it.

There is also an effect noted during listening to 2-channel UHJ-encoded
Ambisonic signals without a decoder, in which the stereo width appears
wider than normal, including generally improved stereo imaging; "beyond
the speakers" images may also be experienced. However while it may be
suggested that listeners to UHJ without a decoder may experience
superior width and imaging, I would not generally call that "Super
Stereo" per se.

Hope this helps...

Best,
-Richard E
Post by Oliver Thuns
Super Stereo is mentioned on several Ambisonics web pages, but I
couldn't find anything specific. I'm not looking for an explanation of
UHJ, which is sometimes used synonymously with Super Stereo, I'm
looking for some documentation on how Super Stereo is implemented in
the classic decoders.
Peter Lennox
2008-09-25 14:58:12 UTC
Permalink
I think you'll find that super stereo use all the available dimensions as predicted in various incarnations of string theory. It's yet to be tested at various spatial scales, as the Hadron Collider is down for repair...

Dr Peter Lennox

Director of Signal Processing and Applications Research Group (SPARG)
School of Technology,
Faculty of Arts, design and Technology University of Derby, UK

***@derby.ac.uk
(01332) 593155
http://sparg.derby.ac.uk/SPARG/Staff_PLX.asp


-----Original Message-----
From: sursound-***@music.vt.edu [mailto:sursound-***@music.vt.edu] On Behalf Of Richard Elen
Sent: 25 September 2008 15:22
To: Surround Sound discussion group
Subject: Re: [Sursound] What is Super Stereo?

"Super Stereo" generally refers to the ability in several Ambisonic
decoders to use subsets of Ambisonic technology to extend the stable
stage width of stereophonic source material. In most cases a stereo
width control is provided which can be used to increase (or decrease)
the width of the soundstage. This is by no means synonymous with UHJ
although some of the UHJ decoder capability may be employed in realising it.

There is also an effect noted during listening to 2-channel UHJ-encoded
Ambisonic signals without a decoder, in which the stereo width appears
wider than normal, including generally improved stereo imaging; "beyond
the speakers" images may also be experienced. However while it may be
suggested that listeners to UHJ without a decoder may experience
superior width and imaging, I would not generally call that "Super
Stereo" per se.

Hope this helps...

Best,
-Richard E
Post by Oliver Thuns
Super Stereo is mentioned on several Ambisonics web pages, but I
couldn't find anything specific. I'm not looking for an explanation of
UHJ, which is sometimes used synonymously with Super Stereo, I'm
looking for some documentation on how Super Stereo is implemented in
the classic decoders.
Oliver Thuns
2008-09-25 17:01:33 UTC
Permalink
"Super Stereo" generally refers to the ability in several Ambisonic decoders
to use subsets of Ambisonic technology to extend the stable stage width of
stereophonic source material. In most cases a stereo width control is
provided which can be used to increase (or decrease) the width of the
soundstage. This is by no means synonymous with UHJ although some of the UHJ
decoder capability may be employed in realising it.
finally found one equation at

http://www.geocities.com/ambinutter/UHJ_and_Ambisonic_equations.html
http://www.geocities.com/ambinutter/Integrex.pdf
Hope this helps...
it does :-)
Martin Leese
2008-09-25 16:43:12 UTC
Permalink
Post by Oliver Thuns
Super Stereo is mentioned on several Ambisonics web pages, but I
couldn't find anything specific. I'm not looking for an explanation of
UHJ, which is sometimes used synonymously with Super Stereo, I'm
looking for some documentation on how Super Stereo is implemented in
the classic decoders.
Here is an old post from Geoffrey Barton
which I carefully preserved:

|| Date: Fri, 19 Dec 2003 09:34:14 -0000
|| From: "Geoffrey Barton" <***@trifield.co.uk>
|| To: Surround Sound discussion group <***@music.vt.edu>
|| Subject: RE: [Sursound] UHJ Coding/Decoding
||
|| On 18 Dec 2003 at 22:41, Martin Leese wrote:
||
|| > The only reference I have ever come across is:
|| > Michael Gerzon, "Multi-System Ambisonic Decoder",
|| > Part 2: "Main Decoder Circuits", Wireless World,
|| > vol. 83 no. 1500, pp. 69-73 (1977 Aug.)
|| >
|| > which on page 72 states that for Super Stereo:
|| > W" = 0.717S - 0.291jD
|| > X" = 0.717S + 0.291jD
|| > Y" = 0.583D
|| > where:
|| > S = Left + Right
|| > D = Left - Right
|| > W", X", Y" are signals inside the decoder (ie, with the
|| > sqrt(2) removed).
|| >
|| > For comparison, the same reference gives the following
|| > equations for decoding 45J (which was similar to UHJ):
|| > W" = 0.998S + 0.107jD
|| > X" = 0.374S - 0.772jD
|| > Y" = 0.132jS + 0.798D
|| >
|| > However, this reference is old (1977)
||
|| as you say; it was already out of date when it was published. There
were various
|| later 'stereo decodes' we tried. By about 1982 we were using something like:-
||
|| W' = 0.6098637*S - 0.6896511*j*w*D
|| X' = 0.8624776*S + 0.7626955*j*w*D
|| Y' = 1.6822415*w*D - 0.2156194*j*S
||
|| where 'w' is a width setting, the optimal (in some senses) value of which is
|| about
|| 0.593, S & D are as defined above. NB, in MAG's notation W'' etc is
the signal
|| after the shelf filter, W' before.
||
|| There are various options, -j can be substituted for j and 'forward
preference'
|| can be added.
||
|| The matrix is then followed by b-format type shelf filters (not UHJ type).
||
|| regds,
|| Geoffrey
--
Martin J Leese
E-mail: martin.leese stanfordalumni.org
Web: http://members.tripod.com/martin_leese/
Richard Lee
2008-09-26 08:04:31 UTC
Permalink
This is a post from 2006. I'd recommend a "Width" control so you can decide how wide you want your stereo.

All the decodes here are basically the same with different "Width" settings. Only minor differences, with preference in Barton 82.

I distinguish between WXY which is strict FuMa and W' X' Y' which already have Shelf Filters applied.

Stereo, SuperStereo use the same Shelfs as FuMa.

UHJ will need different ones which are in Fig 3.3 "SHELF FILTERS for Ambisonic Decoders"
_____________________

Michael's solution circa late 80's and used in most Ambisonic decoders of that period. MINIM

W = 0.3667 M + j 0.3586S M = L + R S = L - R
X = 0.529 M - j 0.404 S
Y = S
Oliver Thuns
2008-09-28 12:43:51 UTC
Permalink
Hi Richard,

thanks for the historical overview of all the SuperStereo variants.
Can anyone report on listening tests for any of these? eg like Steve Thompson. I played a bit 20+ yrs ago but seem to remember the 1977 Integrex was as good as anything fancier. Work really well on Blumlein. Show spaced omnis as crap.
Is anyone listining to stereo recordings in SuperStereo? Does it sound
natural (when you play compatible stereo recordings) or is it more
some "Wow! the sound is all around" effect?
PPS The above encodes (except for the Integrex) are suitable ONLY if the decoder uses full Shelf Filters. If not, you need to use "Energy" playback. see "SHELF FILTERS for Ambisonic Decoders" from ambisonicbootlegs.com
I found it on Ambisonia :-).
Eero Aro
2008-09-28 16:37:42 UTC
Permalink
Post by Oliver Thuns
Is anyone listining to stereo recordings in SuperStereo? Does it sound
natural (when you play compatible stereo recordings) or is it more
some "Wow! the sound is all around" effect?
I used to have the Stereo Enhance (sorry, I don't like the Super Stereo
name, it sounds exaggerated) always active in my Minim decoder. I
listened to all 2-channel material through the Enhance. In my opinion
it sounds quite natural, when you set the "wrapping" control to about 150
degrees of the total 360.

I even listened to Dolby Surround from TV through the Minim Stereo
Enhance, as the Ambisonics decoder doesn't suffer from the pumping
effects of Pro Logic decoders. The Stereo Enhance works very well with
movie sound.

I wouldn't say it's a "Wow! the sound is all around" effect. To me the
maximum enhance setting was quite distracting. With a 150 setting the
sound objects that belong to the front stay there, but the ambience is
nicely wrapped around the listener.

The Enhance was designed into Ambisonic decoders because there was
little UHJ to listen to and most music you could get was plain 2 channel
stereo. With the Enhance mode the decoder wasn't sitting there for nothing.

By the way, in my opinion DTS Neo 6 in Music mode gives pretty well the
same spread of sounds.

Eero
Gerard Lardner
2008-09-28 22:18:25 UTC
Permalink
Like several others here have already suggested, I too listen to most
stereo in SuperStereo mode through my Minim AD10 and also through my
Meridian 561 (I sometimes prefer the Trifield option on the Meridian).
On the Minim I find I prefer only a slight enhancement, with the stereo
enhance control about 90° up from the minimum position. I find this
provides a realistic degree of enhancement, especially for the choral
music I love, and does not over-enhance recordings made with coincident
pair microphones; higher settings also work well for multitrack
recordings, but can sound to me much too "wow" for recordings that I
believe or know were made using some coincident mic techniques.

Gerard Lardner
Post by Oliver Thuns
Hi Richard,
thanks for the historical overview of all the SuperStereo variants.
Can anyone report on listening tests for any of these? eg like Steve Thompson. I played a bit 20+ yrs ago but seem to remember the 1977 Integrex was as good as anything fancier. Work really well on Blumlein. Show spaced omnis as crap.
Is anyone listining to stereo recordings in SuperStereo? Does it sound
natural (when you play compatible stereo recordings) or is it more
some "Wow! the sound is all around" effect?
s***@blueyonder.co.uk
2008-09-28 18:35:56 UTC
Permalink
[Sursound] What is Super Stereo? To: "Surround Sound discussion
Content-Type: text/plain; charset=ISO-8859-1
Is anyone listining to stereo recordings in SuperStereo? Does it
sound natural (when you play compatible stereo recordings) or is it
more some "Wow! the sound is all around" effect?
/lurk mode off

I frequently listen to stereo recordings using SuperStereo in preference
to the DSP "5-channel stereo" facility of my Denon AV amplifier. This
makes use of a prototype Boots/Minim UHJ decoder, vintage 1981 hooked in
via the Denon's external processor loop.

In general - there are always exceptions - I use just a small amount of
width expansion for the majority of orchestral 'classical music'
recordings. Going to the full 150 degree (approx) width doesn't sound
right to me at all. I am used to the sound (and ambience) of live
orchestral music - London's Royal Festival Hall and the Royal Albert
Hall are within easy reach, for example. In all probability, I'm more
comfortable with the orchestra firmly in front of me, with a small
amount of width expansion to push the brass and kitchen departments more
into the sort of audio perspective I'm used to.

However, choral music comes alive given the extra sound-space, and
there's often a good degree of immersion. I've just returned from a
Eucharist service in Westminster Abbey where I was seated immediately
behind the Decani lay vicars, so am well used to being immersed in
choral music. 50 years ago, I was similarly immersed, but as a treble
chorister (Cantoris) in one of our large cathedrals.

In my opinion, SuperStereo comes into its own when used to reproduce
almost anything mixed from multitrack and which never had a "real"
original soundfield. Here, the full width may be used with confidence.

Unlike all DSP "surround" I've heard derived from stereo, there's not
only a sense of immersion, but a sense of warmth and life in the music.
It is also free of some of the distortions often perceived using DSP
to "enhance" stereo, although obviously the original stereo image is
being 'distorted'.

I've played stereo recordings to numerous people, nearly all of them
non-techie and certainly not golden-eared; without exception, all have
been amazed by the sound SuperStereo produces via a 5.1 "home cinema"
set-up, and report that when reverting to the original stereo (bypass
mode), the sound is "lifeless". The next comment invariably is "Were can
I buy one of these? It would sound great for in discotheque as well as
at home."

My system can reproduce the side/rear channels using B&W dipoles mounted
on axis with and 1 metre above the video/audio sweet-spot for normal 5.1
surround, or can be switched to use a rear forward-facing pair. For
ambisonic material, be it UHJ via the decoder or G-format from DTS-CDs,
I always use the rear pair only as there's sufficient stable side imaging.

I certainly prefer not to use the side dipoles for SuperStereo, and
most people that have experienced it on my system seem to concur.


regards
--
Peter Carbines /returning to 'Lurk' mode
Martin Leese
2008-09-28 19:33:20 UTC
Permalink
Post by Oliver Thuns
Is anyone listining to stereo recordings in SuperStereo? Does it sound
natural (when you play compatible stereo recordings) or is it more
some "Wow! the sound is all around" effect?
Did nothing else for five years. It sounds
natural, and if it doesn't then that is what the
width control is for.

There is a wow effect, but more of a "Wow, I
can hear a single, coherent soundfield, and
cannot hear the speakers as sources of
sound". Unlike Eero, I think the name "Super
Stereo" is apt.

Regards,
Martin
--
Martin J Leese
E-mail: martin.leese stanfordalumni.org
Web: http://members.tripod.com/martin_leese/
Eero Aro
2008-09-28 20:17:32 UTC
Permalink
Post by Martin Leese
Unlike Eero, I think the name "Super
Stereo" is apt.
I need to respect your opinion, Martin.

For me, anything "Super" reminds me of Cryptonite and
Men in Tights. :-)

Stereo Enhance in an Ambisonic decoder isn't anything
that ridiculous.

Eero
Steven Dive
2008-09-28 20:27:13 UTC
Permalink
I concur. I've used both a Minim AD10 and my current Merdian 565 (UHJ
2-ch) decoder. I used the Minim with the Enhance control turned about
half way most of the time, or a little under, and the Meridian set to
0.5 typically (scale 0 to 1.5) for acoustic material. Music mixed from
multitrack seems to benefit from almost any width setting one cares to
play with, depending on taste and material. Winding up the width
setting can give a 'wow, it's all around' effect' if that's what you
want. I find this effect a bit distracting and adjust the width to
give a realistically wide front stage, which I find pleasantly
immersive.The speakers do seem to vanish. Almost everyone who hears it
loves it.

Steve
Post by Martin Leese
Post by Oliver Thuns
Is anyone listining to stereo recordings in SuperStereo? Does it sound
natural (when you play compatible stereo recordings) or is it more
some "Wow! the sound is all around" effect?
Did nothing else for five years. It sounds
natural, and if it doesn't then that is what the
width control is for.
There is a wow effect, but more of a "Wow, I
can hear a single, coherent soundfield, and
cannot hear the speakers as sources of
sound". Unlike Eero, I think the name "Super
Stereo" is apt.
Regards,
Martin
Loading...