Re: About importance of "phase" in sound recognition (Bob Carlyon )

Subject: Re: About importance of "phase" in sound recognition From: Bob Carlyon <Bob.Carlyon@xxxxxxxx> Date: Wed, 6 Oct 2010 10:23:24 +0000 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY> --_000_9A9432BC31857848B97F53CEAE8386C4EF1810WSR21mrccbsulocal_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Dear all, When a tone or a resolved harmonic passes through a filterbank there is a p= hase transition. The result of this is that filters with neighbouring CFs r= espond at different phases. When you have two such components the brain is = faced with the task of comparing the outputs of two sets of auditory filter= s, where the filters in each set responding at a wide range of different ph= ases. So to know whether the two tones are in phase or not, the brain woul= d have to know which filters in one set to compare with which filters in th= e other. No wonder it's difficult! When you apply AM to a sound then all filters wax and wane at the same time= . The same is true when you present a filtered pulse train, containing only= unresolved harmonics. If you have two AM sounds or two groups of filtered = pulse trains at the same time then brain can fairly easily tell whether the= y are in phase or not (because it's comparing two sets of auditory filters = where the filters in any one set are responding at the same phase). A model incorporating this idea, and which accounts for several phenomena r= eported in the literature, is as follows: R.P. Carlyon and S. Shamma (2003). "An account of monaural phase sensitivit= y", J. Acoust. Soc. Am., 114, 333-348. Not to be outdone, I can also provide a pdf on request :) Cheers Bob --_000_9A9432BC31857848B97F53CEAE8386C4EF1810WSR21mrccbsulocal_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable <html xmlns:v=3D"urn:schemas-microsoft-com:vml" xmlns:o=3D"urn:schemas-micr= osoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word" = xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"http:= //www.w3.org/TR/REC-html40"> <head> <META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; charset=3Dus-ascii"= > <meta name=3DGenerator content=3D"Microsoft Word 12 (filtered medium)"> <style>  </style>  </head> <body bgcolor=3Dwhite lang=3DEN-US link=3Dblue vlink=3Dpurple> <div class=3DWordSection1> <o:p> </o:p> Dear all,<o:p></o:p> <o:p> </o:p> When a tone or a resolved harmonic passes through a filterba= nk there is a phase transition. The result of this is that filters with neighb= ouring CFs respond at different phases. When you have two such components the brai= n is faced with the task of comparing the outputs of two sets of auditory filter= s, where the filters in each set responding at a wide range of different phase= s.  So to know whether the two tones are in phase or not, the brain would have to know which filters in one set to compare with which filters in the other. No wonder it’s difficult!<o:p></o:p> <o:p> </o:p> When you apply AM to a sound then all filters wax and wane a= t the same time. The same is true when you present a filtered pulse train, containing only unresolved harmonics. If you have two AM sounds or two grou= ps of filtered pulse trains at the same time then brain can fairly easily tell whether they are in phase or not (because it’s comparing two sets of = auditory filters where the filters in any one set are responding at the same phase).= <o:p></o:p> <o:p> </o:p> A model incorporating this idea, and which accounts for seve= ral phenomena reported in the literature, is as follows:<o:p></o:p> <o:p> </o:p> R.P. Carlyon and S. Sh= amma (2003). “An account of monaural phase sensitivity", J. Acous= t. Soc. Am., 114, 333-348. <o:p></o:p> <o:p> </o:p> Not to be outdone, I can also provide a pdf on request </spa= n>J<spa= n style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'= ><o:p></o:p> <o:p> </o:p> Cheers<o:p></o:p> <o:p> </o:p> Bob<o:p></o:p> <pre><o:p> </o:p></pre></div> </body> </html> --_000_9A9432BC31857848B97F53CEAE8386C4EF1810WSR21mrccbsulocal_--

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