For relatively nearby distance detection such as the buzzing bee or whispering or conversation (versus more distant sources such as in a concert hall), one needs to deliver interaural level differences on the order of 10 ot 20 dB with the corresponding ITD of up to 700 microseconds. (If the sources and speakers are relatively centered then we can ignore the pinna distance detection problem.) At the moment I believe only the Choueiri BACCH dummy head recording and crosstalk cancellation method can routinely deliver this magnitude of ILD over the full range of frequencies. If you are synthesizing the ILD in your virtual signals then you don't need to use a dummy head or an Ambiophone. Of course, this ILD seems to apply only for distances to sources at the sides of the head but in practice extreme XTC and thus real binaural ITD provides for proximity at all frontal angles in the horizontal plane as in everyday hearing. RACE, if carefully implemented with directional nearfield speakers, can get up to about 10 dB or more ILD and you might try this since it is easier (cheaper) than using any of the other crosstalk cancelling or WFS or HOA methods. There is no question that Ambiophonic users report enhanced depth perception when listening to ordinary music or the commercially available earphone type binaural recordings but you may want more than this for what you are doing so you should tweak the normal Ambiophonic methodology to optimize ILD capture and reproduction. Ralph Glasgal www.ambiophonics.org
From: Junfeng Li <junfeng.li.1...@gmail.com> To: Surround Sound discussion group <sursound@music.vt.edu> Sent: Saturday, April 16, 2011 9:28 PM Subject: [Sursound] distance perception in virtual environments Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/64a7d936/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/da4e9255/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
