Yes, I know about ambiophonics... But ambiophonics would not work at all
for my use case.
I need an Ambisonics workflow, to work with both FOA and/or
stereo/binaural sources in order to spatialize them in different ways,
then later decide the final rendering options. It's for an interactive
installation, not for an audiophile system.
Thanks anyway for the suggestion.
Marc
Le 21-03-05 à 14 h 38, Ralph Glasgal a écrit :
Checkout the AES papers at www.ambiophonics.org. But basically if you have a
front pair that was recorded with accurate values of ITD and ILD and a rear
pair isolated from the front that also has accurate ITD and ILD then you can
have a full circles of very realistic sound in the horizontal plane using RACE,
BACCH or similar crosstalk cancellation apps with just four speakers. You use
one pair in front less than 20 degrees apart and one to the rear at a similar
angle. This insures that you can have a lots of listeners along the center
line. SQ or 4.0 SACDs sound fantastic this this way and the system is
relatively non critical as to angles and speaker positions. Loudspeaker
binaural (4 speaker type) is also a lot more pinna friendly since the speakers
are central/frontal for dialog soloists, etc. If you make 4.0 recordings using
an Ambiophone then the front and back pairs are isolated and proper ITD and ILD
values are preserved and available to be deliver intact as described above.
Anyone in the NYC area is welcome to hear this in person. Height ambience is
also provided for classical music but that is another topic and one can also
provide envelopment and a rear concert hall ambience for older 2.0 sources like
LPs. Incidentally, in my experience off side Ambiophonics sounds a lot better
than off position Ambisonics probably because both left and right channels are
being outputted by both speakers or if one is close to a side speaker one hears
good mono.
Regards,
Ralph Glasgal
-----Original Message-----
From: Sursound [mailto:sursound-boun...@music.vt.edu] On Behalf Of Dave Hunt
Sent: Friday, March 05, 2021 6:44 AM
To: sursound@music.vt.edu
Subject: Re: [Sursound] binaural to FOA?
Hi Marc,
Yes, this is very difficult to do properly but a simple bodge is surprisingly
effective. Undoing the built in binaural encoding from the original recording
is next to impossible.
I have done what is suggested in the ambisonic.net sources in Max. XY or polar
coordinates place the left and right channels at variable points on a circle in
a 1st order ambisonic encoder, giving a basic B-format output. This image can
then be rotated by fairly simple maths to alter the coordinates of both
channels together, or by rotating the B-format signal. The rest is done by an
ambisonic decoder.
Once in B-format, the WXY components can be manipulated; gain, eq, directional
dominance. You can also apply a Z coordinate to move the image up and down.
The result is undeniably diffuse, but usable. Generally binaural recordings
sound OK as normal stereo, obviously without the proper spatial impression.
Interesting effects are also achieved by treating stereo as UHJ and deriving
B-Format from that. I think there is something on that on ambisonic.net, as
well as super stereo and Dolby stereo.
Transaural crosstalk cancellation only works over a very small area, and
becomes more complex for quad. Many such systems go for some form of closely
spaced dipole speaker layout, possibly with extra speakers. The University of
Southampton had something like that, but references might take some finding.
Ciao,
Dave Hunt
On 4 Mar 2021, at 17:00, sursound-requ...@music.vt.edu wrote:
From: Marc Lavallée <m...@hacklava.net>
Subject: [Sursound] binaural to FOA?
Date: 4 March 2021 at 13:55:42 GMT
To: Surround Sound discussion group <sursound@music.vt.edu>
I have a "back to the basics" question.
For a simple project I planned to record in FOA or HOA, but the final render
would be in simple quad (horizontal). So I don't need a lot of resolution. I
enjoy recording with binaural microphones (the kind that looks like cheap
earbuds), so I can record continuously without being noticed.
So I wondered; is there a method to "convert" binaural to horizontal-only FOA?
Apparently there is:
https://www.ambisonic.net/quaduhj.html
http://www.ambisonic.net/ambimix.html
I guess my question is: what would be the software equivalent of a pan-rotate
device?
Marc
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