Subject: Re: Reference for typical SNRs is public spaces From: Pierre Divenyi <pdivenyi@xxxxxxxx> Date: Sat, 25 Jan 2014 08:32:37 -0800 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>> This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --B_3473483561_12333698 Content-type: text/plain; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable I agree with Bill except for one (crucial) assumption: in a cocktail-party situation the noise is not stationary (although, as Jont Allen once suggested, adding talkers to the babble will make it approach stationarity)= . So, the 0.5 dB SNR is workable in a broad statistical sense and would have to be adjusted almost on a case-by-case basis. -Pierre From: "Richard F. Lyon" <dicklyon@xxxxxxxx> Reply-To: "Richard F. Lyon" <dicklyon@xxxxxxxx> Date: Friday, January 24, 2014 at 10:16 PM To: <AUDITORY@xxxxxxxx> Subject: Re: [AUDITORY] Reference for typical SNRs is public spaces I think Bill's point, which I agree with, is that the SNR is not determined by the noise in the space as much as it is by people trying to communicate. The SNR that he estimates is not "in the space", but rather "at the ears of the listener" when the talker is trying to communicate to that particular listener, above the noise. Other people trying to communicate to different listeners make noise for this one. The SNR is therefore roughly constant, somewhere near 0 dB, almost anywhere that's not too quiet. For me, it's a little higher, after I make people speak up. Dick On Fri, Jan 24, 2014 at 1:51 PM, Bill Woods <Bill_Woods@xxxxxxxx> wrote: > Dear List, > =20 > Since we=B9re assuming Andy is asking about speech-to-noise ratio when refe= rring > to SNR in public spaces, I wondered if the question couldn=B9t be answered = by > back-of-the-envelope calculations using some assumptions and articulation > index theory (AI). > =20 > It turned out there was quite a long list of assumptions behind the > calculation (see below), but the resultant simple calculation yielded a S= NR of > 0.5 dB, which is quite in line with the values other posters have indicat= ed > may actually be present. Two other facts became apparent as I did this, > however, and further motivate my posting. > =20 > First, the long list of assumptions makes apparent the long list of influ= ences > on the SNR in such a situation. These influences need to be characterized= in > any attempt to generalize from SNR measurements in a given scenario, a fa= ct > other posters have alluded to. > =20 > Second, it is important to note that much work has been done recently to = model > or empirically characterize these influences on speech intelligibility, a= nd > that, while the models may require more computational power than found on= the > back of an envelope, they are no problem to execute on current laptop > computers. The implication is that it should not be very difficult to > determine a reasonably-accurate distribution of SNRs over wide variation = in > the assumed listening scenario without any measurements. > Cheers, > Bill > =20 > Bill Woods, PhD > Principal Research Scientist | Starkey Hearing Research Center > 2150 Shattuck Ave. | Suite 408 | Berkeley, CA 94704-1345 > T: 510-845-4876 x 14 <tel:510-845-4876%C2%A0x%C2%A014> > starkey.com <http://www.starkey.com/> | starkeyresearch.com > <http://www.starkeyresearch.com> | map > <http://maps.google.com/maps?q=3D2150+Shattuck+Avenue,+Berkeley,+CA+94704&h= l=3Den& > ll=3D37.869941,-122.268219&spn=3D0.028152,0.038066&sll=3D37.86923,-122.273197&s= spn=3D0 > .056305,0.076132&z=3D15> | email <mailto:william_woods@xxxxxxxx> > =20 > The assumptions are: > 1. Talkers have no hearing loss and no cognitive loss. > 2. The talkers are facing each other and speaking in their =B3mother tongue= =B2. > 3. We know the percent-correct (%C) targeted by the talkers and it is les= s > than 100% (it=B9s a challenging environment). > 4. We know the nature of the speech in such a conversation, from a low-co= ntext > vs. high-context perspective. > 5. The talkers are within their critical distance (i.e., ignore reverbera= tion > of talkers=B9 speech). > 6. We know the long-term spectral shape of speech at the eardrums. > 7. We know the long-term spectral shape of noise at the eardrums. > 8. The noise is stationary. > 9. The noise is diffuse. > 10. The diffuse noise in combination with diotic direct-wave target speec= h > generates the equivalent of an =B3internal=B2 wideband binaural SNR improveme= nt of > ~1.0 dB over monaural listening. > 11. Overall level is not too high (i.e., no =B3roll-over=B2 effect for > intelligibility has occurred). > 12. We=B9re not including lip reading. > =20 > These assumptions allow one to, first, determine the AI needed to achieve= the > assumed target %C given the assumed type of speech, and, second, determin= e the > SNR required with the assumed spectral shapes to obtain that AI. > =20 > For instance, assuming talkers want 95%C with =B3unfamiliar sentences=B2 then > using the polynomial fits from Sherbecoe and Studebaker (JASA 1990) of th= e > ANSI S3.5-1969 transfer functions between AI and %C, our talkers would ne= ed an > AI of 0.45. If we assume the noise and speech have the same long-term spe= ctral > shape then the SNR can be determined from (SNR+12)/30=3D0.45 (staying with = the > 1969 AI method), yielding SNR =3D 1.5 dB. Subtracting the binaural SNR > improvement yields 0.5 dB. > =20 > From: AUDITORY - Research in Auditory Perception > [mailto:AUDITORY@xxxxxxxx On Behalf Of Andy Sabin > Sent: Wednesday, January 22, 2014 9:53 AM >=20 > To: AUDITORY@xxxxxxxx > Subject: Reference for typical SNRs is public spaces > =20 > Hi List,=20 > =20 > Can anyone point me to a reference showing SNRs that are typically observ= ed in > public spaces (e.g., restaurants, bars ...etc)? I can find this info for > overall SPL, but am having a hard time finding it for SNR. > =20 > Thanks > Andy Sabin > =20 >=20 >=20 --B_3473483561_12333698 Content-type: text/html; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable <html><head></head><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: s= pace; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size:= 14px; font-family: Calibri, sans-serif;"><div>I agree with Bill except for = one (crucial) assumption: in a cocktail-party situation the noise is not sta= tionary (although, as Jont Allen once suggested, adding talkers to the babbl= e will make it approach stationarity). So, the 0.5 dB SNR is workable in a b= road statistical sense and would have to be adjusted almost on a case-by-cas= e basis.</div><div><br></div><div>-Pierre</div><div><br></div><span id=3D"OLK_= SRC_BODY_SECTION"><div style=3D"font-family:Calibri; font-size:11pt; text-alig= n:left; color:black; BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; P= ADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4= df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt"><span style=3D"font= -weight:bold">From: </span> "Richard F. Lyon" <<a href=3D"mailto:dicklyon@xxxxxxxx= CM.ORG">dicklyon@xxxxxxxx</a>><br><span style=3D"font-weight:bold">Reply-To:= </span> "Richard F. Lyon" <<a href=3D"mailto:dicklyon@xxxxxxxx">dicklyon@xxxxxxxx= M.ORG</a>><br><span style=3D"font-weight:bold">Date: </span> Friday, Januar= y 24, 2014 at 10:16 PM<br><span style=3D"font-weight:bold">To: </span> <<a = href=3D"mailto:AUDITORY@xxxxxxxx">AUDITORY@xxxxxxxx</a>><br><= span style=3D"font-weight:bold">Subject: </span> Re: [AUDITORY] Reference for = typical SNRs is public spaces<br></div><div><br></div><div dir=3D"ltr"><div>I = think Bill's point, which I agree with, is that the SNR is not determined by= the noise in the space as much as it is by people trying to communicate.&nb= sp; The SNR that he estimates is not "in the space", but rather "at the ears= of the listener" when the talker is trying to communicate to that particula= r listener, above the noise. Other people trying to communicate to dif= ferent listeners make noise for this one. The SNR is therefore roughly= constant, somewhere near 0 dB, almost anywhere that's not too quiet.<br><br= ></div>For me, it's a little higher, after I make people speak up.<br><br>Di= ck<br><br></div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quote">On= Fri, Jan 24, 2014 at 1:51 PM, Bill Woods <span dir=3D"ltr"><<a href=3D"mailt= o:Bill_Woods@xxxxxxxx" target=3D"_blank">Bill_Woods@xxxxxxxx</a>></sp= an> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;borde= r-left:1px #ccc solid;padding-left:1ex"><div><font face=3D"Calibri" size=3D"3"><= span style=3D"font-size:12pt"><div>Dear List,</div><div><font face=3D"Times New = Roman"> </font></div><div>Since we’re assuming Andy is asking abo= ut speech-to-noise ratio when referring to SNR in public spaces, I wondered = if the question couldn’t be answered by back-of-the-envelope calculati= ons using some assumptions and articulation index theory (AI). </div><= div> </div><div>It turned out there was quite a long list of assumption= s behind the calculation (see below), but the resultant simple calculation y= ielded a SNR of 0.5 dB, which is quite in line with the values other posters= have indicated may actually be present. Two other facts became apparent as I did this, however, and further motivate my= posting. </div><div> </div><div>First, the long list of assumptions ma= kes apparent the long list of influences on the SNR in such a situation. The= se influences need to be characterized in any attempt to generalize from SNR= measurements in a given scenario, a fact other posters have alluded to.</div><div> </div><div style=3D"margin-bottom:12pt">Second, it is imp= ortant to note that much work has been done recently to model or empirically= characterize these influences on speech intelligibility, and that, while th= e models may require more computational power than found on the back of an envelope, they are no problem to execute on current lapto= p computers. The implication is that it should not be very difficult to dete= rmine a reasonably-accurate distribution of SNRs over wide variation in the = assumed listening scenario without any measurements. </div><div>Cheers,</div><div>Bill</div><div><font face=3D"T= imes New Roman"> </font></div><table style=3D"width:282.75pt;margin-left:= 5.4pt" width=3D"471"><colgroup><col style=3D"width:282.75pt" width=3D"471"></colgr= oup><tbody><tr><td><font color=3D"#17365D" face=3D"Arial">Bill Woods, PhD<br><fo= nt color=3D"#595959"><span style=3D"font-size:10pt">Principal Research Scientist= | Starkey Hearing Research Center<br> 2150 Shattuck Ave. | Suite 408 | Berkeley, CA = ;94704-1345<br> T: <a href=3D"tel:510-845-4876%C2%A0x%C2%A014" value=3D"+15108454876" targ= et=3D"_blank">510-845-4876 x 14</a> </span></font></font></td></tr><= tr><td><font face=3D"Times New Roman"><a href=3D"http://www.starkey.com/" target= =3D"_blank"><font color=3D"blue" face=3D"Arial"><span style=3D"font-size:10pt"><u>st= arkey.com</u></span></font></a><font color=3D"#0000F6" face=3D"Arial"><span styl= e=3D"font-size:10pt"> </span></font><font color=3D"#595959" face=3D"Arial"><s= pan style=3D"font-size:10pt">|</span></font><font color=3D"#0000F6" face=3D"Arial"= ><span style=3D"font-size:10pt"> </span></font><a href=3D"http://www.starke= yresearch.com" target=3D"_blank"><font color=3D"blue" face=3D"Arial"><span style=3D"= font-size:10pt"><u>starkeyresearch.com</u></span></font></a><font color=3D"#00= 00F6" face=3D"Arial"><span style=3D"font-size:10pt"> </span></font><font co= lor=3D"#595959" face=3D"Arial"><span style=3D"font-size:10pt">|</span></font><font= color=3D"#0000F6" face=3D"Arial"><span style=3D"font-size:10pt"> </span></fo= nt><a href=3D"http://maps.google.com/maps?q=3D2150+Shattuck+Avenue,+Berkeley,+CA= +94704&hl=3Den&ll=3D37.869941,-122.268219&spn=3D0.028152,0.038066&= sll=3D37.86923,-122.273197&sspn=3D0.056305,0.076132&z=3D15" target=3D"_blank= "><font color=3D"blue" face=3D"Arial"><span style=3D"font-size:10pt"><u>map</u></s= pan></font></a><font color=3D"#0000F6" face=3D"Arial"><span style=3D"font-size:10p= t"> </span></font><font color=3D"#595959" face=3D"Arial"><span style=3D"font-= size:10pt">|</span></font><font color=3D"#0000F6" face=3D"Arial"><span style=3D"fo= nt-size:10pt"> </span></font><a href=3D"mailto:william_woods@xxxxxxxx"= target=3D"_blank"><font color=3D"blue" face=3D"Arial"><span style=3D"font-size:10pt= "><u>email</u></span></font></a></font></td></tr><tr><td><font face=3D"Times N= ew Roman"></font></td></tr><tr><td><font face=3D"Times New Roman"></font></td>= </tr></tbody></table><div><font face=3D"Times New Roman"> </font></div><d= iv>The assumptions are:</div><ol style=3D"margin:0;padding-left:36pt"><li>Talk= ers have no hearing loss and no cognitive loss.</li><li>The talkers are faci= ng each other and speaking in their “mother tongue”.</li><li>We = know the percent-correct (%C) targeted by the talkers and it is less than 10= 0% (it’s a challenging environment).</li><li>We know the nature of the= speech in such a conversation, from a low-context vs. high-context perspect= ive.</li><li>The talkers are within their critical distance (i.e., ignore re= verberation of talkers’ speech).</li><li> We know the long-term spectral shape of speech at the eardrums.</li><li>We = know the long-term spectral shape of noise at the eardrums.</li><li>The nois= e is stationary.</li><li>The noise is diffuse.</li><li>The diffuse noise in = combination with diotic direct-wave target speech generates the equivalent o= f an “internal” wideband binaural SNR improvement of ~1.0 dB ove= r monaural listening.</li><li>Overall level is not too high (i.e., no “= ;roll-over” effect for intelligibility has occurred).</li><li>We’= ;re not including lip reading.</li></ol><div><font face=3D"Times New Roman">&n= bsp;</font></div><div>These assumptions allow one to, first, determine the A= I needed to achieve the assumed target %C given the assumed type of speech, = and, second, determine the SNR required with the assumed spectral shapes to = obtain that AI.</div><div> </div><div>For instance, assuming talkers wa= nt 95%C with “unfamiliar sentences” then using the polynomial fi= ts from Sherbecoe and Studebaker (JASA 1990) of the ANSI S3.5-1969 transfer = functions between AI and %C, our talkers would need an AI of 0.45. If we ass= ume the noise and speech have the same long-term spectral shape then the SNR ca= n be determined from (SNR+12)/30=3D0.45 (staying with the 1969 AI method), yie= lding SNR =3D 1.5 dB. Subtracting the binaural SNR improvement yields 0.= 5 dB. </div><div><font face=3D"Times New Roman"> </font></div><div>= <font face=3D"Tahoma"><span style=3D"font-size:10pt"><div class=3D"im"><b>From:</b= > AUDITORY - Research in Auditory Perception [<a href=3D"mailto:AUDITORY@xxxxxxxx= .MCGILL.CA" target=3D"_blank">mailto:AUDITORY@xxxxxxxx</a>] <b>On Behal= f Of </b>Andy Sabin<br></div><b>Sent:</b> Wednesday, January 22, 2014 9:53 A= M<div class=3D"im"><br><b>To:</b> <a href=3D"mailto:AUDITORY@xxxxxxxx" ta= rget=3D"_blank">AUDITORY@xxxxxxxx</a><br><b>Subject:</b> Reference for = typical SNRs is public spaces</div></span></font></div><div class=3D"im"><div>= <font face=3D"Times New Roman"> </font></div><div><font face=3D"Times New R= oman">Hi List, </font></div><div><font face=3D"Times New Roman"> </f= ont></div><div><font face=3D"Times New Roman">Can anyone point me to a referen= ce showing SNRs that are typically observed in public spaces (e.g., restaura= nts, bars ...etc)? I can find this info for overall SPL, but am having a har= d time finding it for SNR. </font></div><div><font face=3D"Times New Roma= n"> </font></div><div><font face=3D"Times New Roman">Thanks</font></div><= div><font face=3D"Times New Roman">Andy Sabin</font></div><div><font face=3D"Tim= es New Roman"> </font></div></div></span></font></div></blockquote></di= v><br></div></span></body></html> --B_3473483561_12333698--