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Date: Sun Jul 15, 2012 8:43 am ((PDT))
David Brinicombe wrote:
> A sonel is a sound pixel. The more separate sonels
> you can hear, the better the stereo image.
It seems that the term "sonel" might be confusing, as it was coined by York=
University researchers Kapralos et al. for a different purpose. For them, =
sonel mapping is a Monte Carlo method for geometric acoustics, using a part=
icle-based method to overcome the limitations of ray-based techniques.
I believe instead it is more appropriate to follow Mills' vocabulary of the=
minimum audible angle (MAA), which refers to the smallest detectable amoun=
t of sound source displacement. Like other JNDs (just noticeable difference=
s) it depends on the frequency of the source. Remarkably, this can be as pr=
ecise as 1 degree (at 500 Hz), but of course this was in a tightly controll=
ed listening environment.
Using MAA to measure the quality of a location recording is a different mat=
ter -- but is an intriguing possibility! Certainly a listener would be able=
to distinguish a lot more than 3 or even 9 distinct sound source positions=
... likely more than 20. This makes sense when one considers that we hear a=
moving source in the stereo field tracing a smooth path, and not jumping f=
rom one discrete position to another.
Refs:
Kapralos, B., Jenkin, M., and Milios, E. (2006) "Sonel mapping: A stochasti=
c acoustical modeling system". Proceedings of the IEEE International Confer=
ence on Acoustics, Speech and Signal Processing.
Mills, A. W. (1958) "On the minimum audible angle". Journal of the Acoustic=
al Society of America 30.4, 237=96246.
-- Robin Parmar
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