Quote:
Originally posted by kempfand
Steve,
I can only give some general information to your question.
Ambisone: It's a bit unclear as to what they really do, and they don't disclose anything. I think you better look at at WaveArt's WaveSurroundA VST doing similar things but much better documented and coming from someone with a very prooved track-record (Bill Gardiner).
SpinAudio: Uses XTC (cross-talk concellation). Basically the same topic as the Stereo Dipole I published erlier in this thred (using filters made available by Farina) as well as the XTC VST (including custom-made filter) by Species. SpinAudio's 3D Panner Studio has excellent help files.
For general introduction, see: ISVR Stereo Dipole as well as the related demo WAV files (but you need the closely spaced speakers for the demo to work coorectly).
On howto implement vertical decoding, see Miller's papers (http://www.filmaker.com/papers.htm, with the i, j, k decodings) as well as the VST's published by "Species" here (IMHO, they are excellent, but that's my personal taste).
Regarding "missing ambience from over the head would be very cool if somehow synthesized": I had a very similar thought and once called it "virtual Z restorer/panner" (meaning that Z/horizontal could be created from WXY, even when 'just' using artificall algorithms). That would be really cool indeed.
On howto use one speaker of current ITU-5.1 sytems for vertical informatation (i.e. one of the 5-6 speakers used for decoding vertical data), I just know that Farina, Malham, and others are aware of the the need for more research on this, and that there are efforts on this front, but this is very early work-in-progress and we have to take it as 'teaser' of what to expect over the next 12-24 months.
Sorry for the limited answer (have to leave for a ahort business travel) but hope this helps.
Andreas
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Thanks for your answers, Andreas. Actually, I've tried Ambisone, Wavesurround, and the Spin Audio stuff. Personally I've found that the Ambisone gives the most realistic sounding horizontal directionality. It does have an elevation setting, but this doesn't seem to accomplish very much. If one closes his eyes and concentrates, there is some sense of difference among the various elevation levels, but how much of it is real and how much is sort of created by the power of "suggestion" or expectation? What I mean by that is, if one expects the sound to give a sense of vertical space, does he or she "fill in" missing psychoacoustic information, or is it actually there?
I still would love to get my hands on whatever the H2O team used for a 2-channel sound file that played during one of their install routines I once tried. It gave an incredibly realistic impression of water bubbling from the front in stereo and then out from the center over the listener's head. It was quite astounding in its realism.
I'm also wondering about Maven 3D Pro. This is a program that looks quite impressive, handles multichannel files, etc., but no one seems to talk about it on here or on any of the other sound forums. I tried the demo once but I didn't have the time to master it to the point where I could do much with it before it expired.
Thanks for the tips concerning Species 8472's VSTs. I'd downloaded them and tried to do something, but the center pages of this thread can tend to be a complete blur. Everyone was uploading bidules and VSTs around the same time and the details on each method didn't seem to get thoroughly discussed.
As for the Ambisonic decoding, I've tried playing around with some stuff but, while I get some interesting horizontal effects--especially when boosting the Y channel width info as in UpMix Studio-- I still haven't had much success with anything vertical. The same old problem arises, trying to apply Ambisonic encoding and decoding to sonic material that was not recorded for Ambisonics. The information just isn't there, so one must--as you said--apply artifical algorithms.
With the right HRTF processing some sense of vertical space should be possible. Or, perhaps some impulse responses with height info could be used to create b-format files with the Z info.
Have a good weekend,
Steve.