Subject: Re: auditory localization From: Peter Lennox <peter(at)LENNOX01.FREESERVE.CO.UK> Date: Sun, 9 May 2004 10:39:37 +0100You haven't said whether you will be encoding the required inter-aural differences to the loud speakers in such a way that you would only place 'images' in the speakers, or conversely using speaker pairs (or other configuration) to make inter-speaker imagery. If it were the second case, then cross talk and room acoustic would confound the intended interaural differences and the method of generating the 'phantom image' has a significant impact on results; indeed, speakers used behind the 90-degree axis can aid localisation and 'focus' of images in the frontal plane. If you are restricting images to actual speaker locations (so that a given signal is only ever fed to one speaker at a time), then you'd need quite a lot of speakers to cater for the notional acuity of 1-2 degrees aroud the 0 degree azimuth, elevation point. Also, if the room isn't anechoic, then the directivity pattern-with-frequency is a problem for IIDs and ITDs, and speakers can be spectacularly poor localisation 'targets' when compared to many 'real' sources. This is without taking into account interactions with visual stimulus-characteristics, which I see someone else has pointed out. good luck, regards ppl ----- Original Message ----- From: "Elyana Makowski" <elyana_makowski(at)hotmail.com> To: <AUDITORY(at)LISTS.MCGILL.CA> Sent: 07 May 2004 14:30 Subject: auditory localization > Hi, > I am a PhD student and my research project is on the use of localization > cues (ILD and ITD) in the horizontal plane. My set up consists of 11 > speakers arranged at 18 degree intervals from -90 to +90 degrees in the > azimuthal plane. Currently, I have tested normally hearing subjects, and > will soon be testing hearing aid users and cochlear implant users. > Recently, an issue has been brought up as to the number of speakers that I > am using, with the suggestion being made that better results could be > measured if I used more speakers. My question is does anyone know how many > speakers are necessary to accurately measure the average localization error? > How many speakers are enough? > Thank you, > Elyana > > _________________________________________________________________ > It's fast, it's easy and it's free. Get MSN Messenger today! > http://www.msn.co.uk/messenger