cochlear-amplifier (Mitchell Cotter )


Subject: cochlear-amplifier
From:    Mitchell Cotter  <mcotter7@xxxxxxxx>
Date:    Thu, 7 Apr 2011 14:53:09 -0400
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

--0016e6da9340df6eb404a0589ea7 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable April 7, 2011 To: Andrew Bell, Michael Rapson and the cochlear-amplifier@xxxxxxxx In reading the many comments on the properties of the cochlear-neural processing of sounds I note some concepts that do not seem to be given much attention in the discussions, though generally there is acceptance of the presence of some active amplifying processes in the sensory system. I offer consideration of a few points that may aid integrating the various observations and theories towards understanding better, the whole-animal response as part of the concerns. *+* The response of both ears via the CNS should be fully considered in evaluating the role played by the various elements of the peripheral sensors, which should also include the whole body sensing of very long wave length acoustic energy. *+*Note for example, that the ISO-220 (2003) revised *Equal Loudness Curves*reveal an *extraordinary* rise in low frequency SPL required for equal loudness, over the entire spectrum below 1 Khz. A look at those curves also shows tha= t the threshold across the range below 1 kHz is correspondingly extremely elevated. These 2003 curves show that*:* *@xxxxxxxx 31.5 Hz* free field Equal Loudness sound of 20 phon requires *77dB more SPL *than the 1* kHz SPL; = *40 phon requires *34dB more SPL *and* *80 phon requires *30 dB more SPL // FURTHER note that* *at 63 Hz* the increases for equal loudness are somewhat smaller; 20 phon requires *48 dB more SPL *than the 1 kHz SPL; 40 phon requires *33 dB more SPL; *80 phon requires *18 dB more SPL .* This loss of sensitivity at the longer wavelengths corresponds with the relative increased level of what might be termed background low frequency noise level from natural low frequency energy (even in a natural environmen= t outside of populated areas). The role of noise =96 particularly 1/f noise as a stimulating component of sensors (dither?) should also be considered as part of the system analysis and of course in model development. *+ *Interestingly, a* *whole animal body responds to acoustic and ground or contact-borne long wavelength vibration. This all suggests that the role of sensory processes should be considered from a perspective of the *entire information receiving system *=96 i.e. whole animal response. It=92s not just =93Das Ohr=94 but the whole system response to radiation of =93acoustic=94 vibratory energy and the information it carries. Regards to all, Mitchell Cotter mcotter7@xxxxxxxx --0016e6da9340df6eb404a0589ea7 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable <style>=A0<!-- /* Font Definitions */ @xxxxxxxx {font-family:"Times New Roman"; panose-1:0 2 2 6 3 5 4 5 2 3; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:50331648 0 0 0 1 0;} @xxxxxxxx {font-family:Arial; panose-1:0 2 11 6 4 2 2 2 2 2; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:50331648 0 0 0 1 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman";} p.MsoFooter, li.MsoFooter, div.MsoFooter {margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; tab-stops:center 3.0in right 6.0in; font-size:12.0pt; font-family:"Times New Roman";} a:link, span.MsoHyperlink {color:blue; text-decoration:underline; text-underline:single;} a:visited, span.MsoHyperlinkFollowed {color:purple; text-decoration:underline; text-underline:single;} p {margin-right:0in; mso-margin-top-alt:auto; mso-margin-bottom-alt:auto; margin-left:0in; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times;} table.MsoNormalTable {mso-style-parent:""; font-size:10.0pt; font-family:"Times New Roman";} span.msoIns {mso-style-type:export-only; mso-style-name:""; text-decoration:underline; text-underline:single; color:teal;} @xxxxxxxx Section1 {size:8.5in 11.0in; margin:.5in .9in .7in .9in; mso-header-margin:0in; mso-footer-margin:0in; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style> <p><span style=3D"font-size:11.0pt;font-family:Arial">April 7, 2011</span><= /p> <p><span style=3D"font-size:11.0pt;font-family:Arial">To: Andrew Bell, Mich= ael Rapson and the <a href=3D"mailto:cochlear-amplifier@xxxxxxxx= s.org">cochlear-amplifier@xxxxxxxx</a></span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial">In reading the many comments on the properties of the cochlear-neural processing of sounds I no= te some concepts that do not seem to be given much attention in the discussion= s, though generally there is acceptance of the presence of some active amplify= ing processes in the sensory system.<span style=3D"mso-spacerun: yes">=A0=A0=A0 </span>I offer consideration of a few points that may aid integrating the various observations and theories towards understanding better, the whole-animal response as part of the concerns.</span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial"><b>+</b></span><span = style=3D"font-size:11.0pt;font-family:Arial"> The response of both ears via= the CNS should be fully considered in evaluating the role played by the various elements of the peripheral sensors, which should also include the whole bod= y sensing of very long wave length acoustic energy. </span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial"><b>+</b></span><span = style=3D"font-size:11.0pt;font-family:Arial">Note for example, that the ISO= -220 (2003) revised <b>Equal Loudness Curves</b></span><span style=3D"font-size:= 11.0pt; font-family:Arial"> reveal an <b>extraordinary</b></span><span style=3D"fon= t-size:11.0pt;font-family:Arial"> rise in low frequency SPL required for equal loudness, over the entire spectrum below 1 Khz.<span style=3D"mso= -spacerun: yes">=A0=A0=A0=A0=A0 </span>A look at those curves also shows that the threshold across the range below 1 kHz is correspondingly extremely elevated.<span style=3D"mso-spacerun: yes">=A0=A0 </span>These 2003 curves show that<b>:</b></span><span style=3D"font-size:1= 1.0pt; font-family:Arial"><span style=3D"mso-spacerun: yes">=A0 </span><b>@xxxxxxxx 31.5 H= z</b></span><span style=3D"font-size:11.0pt;font-family:Arial"> free field = Equal Loudness sound of <span style=3D"mso-spacerun: yes">=A0</span>20 phon= requires <b>77dB more SPL </b></span><span style=3D"font-size:11.0pt;font-= family:Arial">than the 1<b> kHz<span style=3D"mso-spacerun: yes">=A0 </span= >SPL;<span style=3D"mso-spacerun: yes">=A0 </span></b></span><span style=3D"font-size:11.0pt;font-family:Aria= l">40 phon<span style=3D"mso-spacerun: yes">=A0 </span>requires <b>34dB<span styl= e=3D"mso-spacerun: yes">=A0 </span>more SPL </b></span><span style=3D"font-= size:11.0pt;font-family:Arial">and<b> </b></span><span style=3D"font-size:1= 1.0pt;font-family:Arial">80 phon<span style=3D"mso-spacerun: yes">=A0 </span>requires<span style=3D"mso-spacerun: yes">=A0=A0=A0=A0 </span><b>30 dB more SPL //<span style=3D"mso-spacerun: y= es">=A0=A0=A0 </span>FURTHER note that</b></span><span style=3D"font-size:1= 1.0pt;font-family:Arial"></span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial"><span style=3D"mso-sp= acerun: yes">=A0</span><b>at 63 Hz</b></span><span style=3D"font-size:11.0pt; font-family:Arial"> the increases for equal loudness are somewhat smaller; = 20 phon requires<span style=3D"mso-spacerun: yes">=A0=A0 </span><b>48 dB more SPL </b></span><span style=3D"font-size:11.0pt;font-family:Arial">than the = 1 kHz SPL;<span style=3D"mso-spacerun: yes">=A0 </span>40 phon requires <b>33 dB more SPL; </b></span><span style=3D"font-size:11.0pt;font-family:Arial">80 = phon requires <b>18 dB more SPL .</b></span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial">This loss of sensitiv= ity at the longer wavelengths corresponds with the relative increased level of wha= t might be termed background low frequency noise level from natural low frequ= ency energy (even in a natural environment outside of populated areas).</span></= p> <p><span style=3D"font-size:11.0pt;font-family:Arial">The role of noise =96 particularly 1/f noise as a stimulating component of sensors (dither?) shou= ld also be considered as part of the system analysis and of course in model de= velopment.</span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial"><b>+ </b></span><span= style=3D"font-size:11.0pt;font-family:Arial">Interestingly, a<b> </b></spa= n><span style=3D"font-size:11.0pt;font-family:Arial">whole animal body resp= onds to acoustic and ground or contact-borne long wavelength vibration. This all suggests that the role of sensory processes should be considered from a perspective of the <i>entire information receiving system </i></span><span = style=3D"font-size:11.0pt;font-family:Arial">=96 i.e. whole animal response= .<span style=3D"mso-spacerun: yes">=A0 </span></span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial">It=92s not just =93Da= s Ohr=94 but the whole system response to radiation of =93acoustic=94 vibratory energy a= nd the information it carries.<span style=3D"mso-spacerun: yes">=A0 </span></span>= </p> <p><span style=3D"font-size:11.0pt;font-family:Arial">Regards to all,</span= ></p> <p><span style=3D"font-size:11.0pt;font-family:Arial">Mitchell Cotter</span= ></p> <p><span style=3D"font-size:11.0pt;font-family:Arial"><a href=3D"mailto:mco= tter7@xxxxxxxx">mcotter7@xxxxxxxx</a></span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial">=A0</span></p> <p><span style=3D"font-size:11.0pt;font-family:Arial"><span style=3D"mso-ta= b-count: 1">=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 </span></span></p> --0016e6da9340df6eb404a0589ea7--


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