Last night I coded up a quick experiment in using the Kemar mannequin HRTFs published by Algazi, et al. at UC Davis. http://interface.cipic.ucdavis.edu/sound/hrtf.html
It is very simple... simulate Blumlein pickup and playback though speakers at +/- 45 degrees, low-pass at 800 Hz, and use cross-correlation to estimate the ITDs, and compare to the natural hearing case. The result is here http://www.ai.sri.com/ajh/ITDs_Blumlein_vs_Natural/ I was pleasantly surprised that such a simple experiment yield such a clean result. The 800 Hz LPF is needed to get reliable results from the crosscorrelation. As you point out, humans may use the higher frequency information (I'd like to see a citation for that), but the point here is that accurate ITDs are present in the ear signals in stereo playback even though the soundfield has been sampled at a single point in space. The MATLAB code is here: http://www.ai.sri.com/ajh/ITDs_Blumlein_vs_Natural/itd_blumlein_plot.m As Eric has pointed out, Braanch (and many others) have done much more on this, for example: Braasch, Jonas, "A Binaural Model to Predict Position and Extension of Spatial Images Created with Standard Sound Recording Techniques", AES Preprint 6610. http://www.aes.org/e-lib/browse.cfm?elib=13352 http://www.aes.org/e-lib/browse.cfm?elib=13352 -- Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US On Tue, Apr 3, 2012 at 3:01 PM, Robert Greene <gre...@math.ucla.edu> wrote: > > Thanks everybody for the links and in particular the > calculation of models link. I shall work on that one > I know the Lipshitz paper well, but it seems that > experts disagree. James Johnston has told me > a number of times for example that he thinks > getting those time cues from ORTF is really > important and that pure Blumlein is really > not the way to go because they are missing. > > So... in this corner expert 1, Stanley L and > in the opposite corner expert 2 ,JJ. What's a body to do? > > Thanks again > Robert > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
