The basic premise for
crosstalk is that one ear hears information that is "meant" for the other ear, and hears it slightly delayed due to the longer path length to that ear from the speaker.
- This "crosstalk" is what prevents more accurate imaging in both lateral location and depth perception, because the original sound is smeared by presenting the sound TWICE to each ear rather than once. End quote.
It gets worse than that. In reality, stereophonic hearing is a sonic illusion and like an optical illusion it is rather unstable or better said does not and can never deliver the physiological versimilitude that normal everyday binaural hearing delivers. Stereophonic hearing is not the same as binaural hearing. The use of the stereo loudspeaker triangle limits the interaural time delay to a maximum of about 220 microseconds compared to normal hearing of up to 700 microseconds and reduces the interaural level differences to the range of or or five dB compared to 15 to 20 dB in normal hearing or about 10 for concerts. The higher values are experienced when the bee buzzes around your head and it is these extreme values of ILD that Prof. Choueiri is attempting to deliver thus requiring speakers and software that is unusual. Standard Ambiophonics is more for music, games, movies, surround sound and thus is much more forgiving as to speaker types.
Addtionally concerning crosstalk, the human ear pinna are very sensitive to the direction from which the frequencies over 1000 Hz come from. In the stereo triangle this pinna angle is always 30 degrees and so it is wrong for the more critical central region where soloists are etc. But worse at these higher frequencies, there is a sequence of peaks and dips for central or even near side sources reaching each ear from each speaker that mimic pinna direction finding patterns aand these contradict the lower frequency level and time difference cues and thus tell the brain that the music is canned lacks depth, etc. What is more, for central souces the fact that both speakers reach both ears and that at bass frequencies there little loss across the head, there is a doubling of center energy compared to side sound in the bass region. Again, for a side sound, only one speaker is heard at both ears, for a mono or solo center two speakers sound out to both ears doubling the level. There is no way for a recording enginner to correct for this unless the center channel is mono as in spot mic'd.
Of course, like Black and White photography, one can regard stereo with all its quirks as an artform that is not expected to be realistic. What really happens is that color LPs and CDs are reproduced in black and white. All that localization data on the average recording is simply not reproduced or not reproduced with any accuracy.
One example. Let us say a sound from the extreme side is recorded with a time delay in the stereo recording of 700 microseconds. When this is played back via a speaker at 30 degrees the maximum delay is reduced to 220 microseconds and the image is no longer at the side but at the 30 degree point.
You don't have to take my word for all this. There are a lot of demo tracks you can play with on the Ambiophonic website. Some are preprocessed and you can just play them if you move two speakers to one third their normal spacing or listen to them via your laptop or PC speakers. In brief Ambiophonics or Ambio is simply a loudspeaker binaural 2D, 3D methodology that is tweakable just like the stereophonic or 5.1 methodology.
