Subject: Re: [AUDITORY] Localizing smoke detectors - why is it so hard? From: Kevin Austin <kevin.austin@xxxxxxxx> Date: Tue, 25 Jun 2013 07:23:06 -0400 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>
In my house, all of the smoke detectors are in reverberant field = conditions and are a point source, on a surface, in stairwells. The = sound wave would appear to come from 'everywhere' over my head. I have = the same trouble locating the microwave over by ear. The results are = skewed because I know where the devices are however. Kevin On 2013, Jun 25, at 5:40 AM, Leslie Smith <l.s.smith@xxxxxxxx> = wrote: > 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 altitude=85 >=20 > --Leslie Smith >=20 > On 25 Jun 2013, at 09:46, Jennifer M. Groh wrote: >=20 >> Dear List, >>=20 >> I am writing a book for a general audience on how the brain processes = spatial information ("Making Space"). The chapter on hearing covers many = topics in sound localization, but there is one that I'm currently still = quite puzzled about: why it is so hard to localize a smoke detector when = its battery 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 feedback, i.e. changes in ITD and ILD as the head turns during a = sound. However, in my laboratory we have obtained excellent sound = localization performance 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 such 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 >> --=20 >> Jennifer M. Groh, Ph.D. >>=20 >> Professor >> Department of Psychology and Neuroscience >> Department of Neurobiology >> Center for Cognitive Neuroscience >>=20 >>=20 >> B203 LSRC, Box 90999 >> Durham, NC 27708 >>=20 >> 919-681-6536 >> www.duke.edu/~jmgroh >=20 > 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 =20 > Tel (44) 1786 467435 Fax (44) 1786 464551 > www http://www.cs.stir.ac.uk/~lss/ >=20 >=20 >=20 >=20 >=20 >=20 >=20 > --=20 > The University of Stirling is ranked in the top 50 in the world in The = Times Higher Education 100 Under 50 table, which ranks the world's best = 100 universities under 50 years old. > The University of Stirling is a charity registered in Scotland,=20 > number SC 011159.