Ambisonics?

[Robin Faichney]

On BBC R3 last night there was a programme on computer music
(fascinating, too -- if only I'd taped it!) before which it was
announced that some binaural material would be included.

As I didn't fancy wearing my phones for an hour, and I was listening in
bed, and my speakers are switched, I wasn't going to worry about the
binaurality, until, just before the piece concerned, they said that it
was made using a system called Ambisonics, developed in Birmingham
(UK), which would produce a sphere of sound around the listener's
head! Of course I jumped up, found the phones, plugged them in, put
them on, adjusted the volume, went back to bed, and -- nothing. The
sound stage went right through my head, as usual.

So, anyone else hear this prog -- did it work for you? Did you tape
it? Anyone know anything about Ambisonics?

[Timothy J. Stone in New York]

I think that the Ambisonics system was developed by Peter Craven of the
(then) Oxford University Mathematical Institute and Professor Felgett
(spelling ?) of (then) Reading University in the early/mid 1970s. It
is a fairly rigorous 3 dimensional sound system and is in current
use by Nimbus Records on most if not all their CDs. Surround
sound suffered from a tarnished image in the later 1970's because of
the abortive efforts of systems like the JVC attempt to put 4 channels onto
black vinyl LPs. Ambisonics never really caught on because of the
image problem. The system does deserve a thorough critical review now
that a good supply of source material is available.

An adapter to decode Ambisonics CDs into the 4 separate channels is currently
advertised by a company called

Minim Electronics Ltd., Lent Rise Road, Burnham, Slough SL1 7NY, England
telephone (06286)-63724.

I am not associated with any of these companies but heard some of the early
experiments using the system which were very impressive.
--
Tim Stone
S.G. Warburg & Co., Inc. => UUCP: t...@warburg.COM
787 Seventh Avenue, => Tel : (212) 459-7065
New York, NY 10019, U.S.A. => Fax : (212) 459-7038

[David Morning]

I remember back in the 1970s binaural sound was a buzzword briefly. There were
a number of binaural recordings made but it eventually went the way of
quadraphonic sound i.e. it disappeared. I think the problem with it was
that you had to wear headphones all the time.
Tangerine Dream are a likely candidate for a binaural recording so it might
be worth digging out some of their old 70s' stuff.(I vaguely remember an LP
cover with one of those polystryrene dummy heads used in shop windows with a
pair of headphones on).
I don't know know the name of the LP since I'm not a fan.

Dave

[Siri Hewa]

>announced that some binaural material would be included.
>

>head! Of course I jumped up, found the phones, plugged them in, put
>them on, adjusted the volume, went back to bed, and -- nothing. The
>sound stage went right through my head, as usual.
>
>So, anyone else hear this prog -- did it work for you? Did you tape
>it? Anyone know anything about Ambisonics?

The company I use to work in UK(AVS) surrey use to own the patent to ambisonic.
I use to design some filters to it.Although AVS is mainly into top end
broadcast manufacturing .
To hear this you have to buy the decoder first.It is bit like early days
quadrophonic receivers. Another thing is you need 4-ch amplifiers as well.Not
2-ch amps multiplexed.
We developed car units first,but we found time we spend was not worth so we
sold the rights to some co in croyden.
I still got one of those 4-ch car amps at home.

Siri Hewa
||||OTC||
R&D Visual Communications
Australia
si...@otc.otca.oz.au

[lance.norskog]

I haven't looked all that hard in the libraries, but
the only mathematical treatment of stereo sound synthesis that I've
managed to find is in the latest issue of the Computer Music Journal,
Feb. 1991. The article is by someone at CCRMA, Stanford University.
I don't remember if it was just her, or 'et al'.

They ran pairs of speakers off of Midi-controlled synths with Midi reverbs
feeding the pairs, and built a system for the Mac that does 2D sound
placement given N synth/reverbs and N speaker pairs. The Mac just sent
out MIDI data.

To calibrate a configuration, they just set up
all the speakers in the target configuration, put digitizing mikes in the
middle, ran the speakers off of MIDI-controlled synths and calibrated
the reverb times and sound levels according to their sound model.
They take the input data and do a curve-fit into their model,
then do quite a bit of trig. to create the output equation model.

Sounded very spiffy, if it could be incorporated into a larger
MIDI sequencer.

Lance