Subject: Re: [AUDITORY] Localizing smoke detectors - why is it so hard? From: "Maher, Rob" <rmaher@xxxxxxxx> Date: Tue, 25 Jun 2013 08:10:14 -0600 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>
I would suspect that multipath plays a big role. The listener "down the ha= ll" is not hearing the direct sound, but the reflected/reverberant sound wi= th its largely ambiguous directionality. It's usually not a free-field sit= uation. Rob -----Original Message----- From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx= ILL.CA] On Behalf Of Leslie Smith Sent: Tuesday, June 25, 2013 3:41 AM To: AUDITORY@xxxxxxxx Subject: Re: Localizing smoke detectors - why is it so hard? I wonder if the fact that it's above your head makes a difference - people = are generally better at localisation in azimuth horizontally than at altitu= de... --Leslie Smith On 25 Jun 2013, at 09:46, Jennifer M. Groh wrote: > Dear List, >=20 > I am writing a book for a general audience on how the brain processes spa= tial information ("Making Space"). The chapter on hearing covers many topic= s in sound localization, but there is one that I'm currently still quite pu= zzled about: why it is so hard to localize a smoke detector when its batter= y starts to fail? Here is what I have considered so far: >=20 > - To my ear, the chirp sounds high frequency enough that ILD cues should = be reasonably large. >=20 > - At the same time, it seems to have a broad enough bandwidth, and in any= case it has onset-and-offset cues, that ITD cues should be usable. >=20 > - A possibility is that the chirp is too brief, and that limits dynamic f= eedback, i.e. changes in ITD and ILD as the head turns during a sound. Ho= wever, in my laboratory we have obtained excellent sound localization perfo= rmance in head-restrained monkeys and human subjects localizing sounds that= are briefer than the reaction time to make an orienting movement. >=20 > - An additional possibility is that we have too little experience with su= ch sounds to have assembled a mental template of the spectrum at the source= , so that spectral cues are of less use than is normally the case. >=20 > I'm leaning towards a combination of the last two factors, which together= would render the cone of confusion unresolved for these stimuli. >=20 > Thoughts? >=20 > Best wishes, >=20 > --Jennifer Groh >=20 > -- > Jennifer M. Groh, Ph.D. >=20 > Professor > Department of Psychology and Neuroscience Department of Neurobiology=20 > Center for Cognitive Neuroscience >=20 >=20 > B203 LSRC, Box 90999 > Durham, NC 27708 >=20 > 919-681-6536 > www.duke.edu/~jmgroh Professor Leslie S. Smith B.Sc. Ph.D. SMIEEE, Head, Institute of Computing = Science and Mathematics, School of Natural Sciences University of Stirling,= Stirling FK9 4LA, Scotland l.s.smith@xxxxxxxx Tel (44) 1786 467435 Fa= x (44) 1786 464551 www http://www.cs.stir.ac.uk/~lss/ -- The University of Stirling is ranked in the top 50 in the world in The Time= s Higher Education 100 Under 50 table, which ranks the world's best 100 uni= versities under 50 years old. The University of Stirling is a charity registered in Scotland, number SC = 011159.