Dear Madam or Sir, I would like to stop becoming email from this list. Please could you take my name ''Thomas Guignard'' under the email ''t-guignard@xxxxxxxxxx" off the list. Best regards, Thomas Guignard > Date: Fri, 14 Nov 2008 11:43:50 +0100 > From: auditorylist@xxxxxxxxxxxx > Subject: HRTF failure > To: AUDITORY@xxxxxxxxxxxxxxx > > Dear List, > > We encounter a problem when trying to place a sound at a virtual > position in space by means of head related transfer functions (HRTF). > > We use sounds from the IAPS database (International Affective Digitized > Sounds System, Bradley & Lang) as well as simple white noise of six > seconds duration. We use the Kemar HRTF, the "compact data" with zero > elevation. We convolve the original sound data with the HRTF data as > suggested in the documentation. The final sounds are presented using > Beyer Dynamic DT770 headphones. > > We have tested the precision with which our sounds are placed in virtual > space, by presenting them to eight listeners. The listeners had a > touchscreen lying on their lap, with a circle plotted on it, and they > could indicated the direction where they perceived that the sound came > from. We presented to them in total 144 sounds, 72 noises and 72 IAPS > sounds, coming from 36 virtual directions (0°, 10°, 20°...) in > randomized order. > > The results are shown in a figure that I put in the internet: > http://www.uni-kiel.de/psychologie/emotion/hrtf/direction.gif > The red dots are from IAPS sounds, the yellow dots are from the noises. > The x-axis shows the "true" (virtual) angle, the y-axis shows the > estimated angle. As can be seen in this figure, listeners could well > discriminate between sounds from the left and sounds from the right. But > not more than that. There is a certain reduction of variance for sounds > coming from 90° and from 270°, but there is no correlation with angle > within one hemifield. > > Now we are eager to learn from you: What could be the cause for this > failure? > > A) HRTFs are not better than that. > B) The headphones are inadequate. > C) It must be a programming error (we don't think so) > D) .... > > We are grateful for any help in interpreting the possible cause for this > failure. > > Thank you very much in advance, > Chris > > -- > Christian Kaernbach > Christian-Albrechts-Universität zu Kiel > Germany > www.kaernbach.de Connect to the next generation of MSN Messenger Get it now! |