Re: Reference for typical SNRs is public spaces ("Smits, Cas" )


Subject: Re: Reference for typical SNRs is public spaces
From:    "Smits, Cas"  <C.Smits@xxxxxxxx>
Date:    Sun, 26 Jan 2014 09:54:31 +0000
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

--_000_5801ADC15F4A8D4CAC8F4B3195FA6327EF3B322BSPMXMBX32vumcnl_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable We used a method to determine the relation between AI/SII and SNR for fluct= uating noise in a way quite similar to the way Bill proposed (Smits and Fes= ten, 2013). We found a different relationship between SII and SNR for two-b= and speech modulated noise compared to steady-state noise (a 2-dB increase = in SNR for fluctuating noise gives almost the same increase in SII as a 1-d= B increase in SNR for steady-state noise). This method works well in lab se= ttings but I think the uncertainties are too large to make reliable predict= ions for real-life situations. The effects of speaking style, speech materi= al, talker etc on percentage correct (the speech recognition function) are = large and the (backward) calculations give large uncertainties in SNR estim= ates. In situations with fluctuating noise the use of the steady-state nois= e relationship between SII and SNR could give large errors. With interferin= g talkers (informational masking) things get even more complicated. But, coming back to the question, normal-hearing listeners can follow most = conversations in public spaces with some difficulty (often in situations wi= th multitalker babble which is very similar to stationairy noise). Thus, SN= Rs around 0-5 dB SNR sounds plausible... Cas Smits Smits C, Festen JM. The interpretation of speech reception threshold data i= n normal-hearing and hearing-impaired listeners: II. Fluctuating noise. J Acoust Soc Am. 2013 May;133(5):3004-15 dr.ir. J.C.M. (Cas) Smits, klinisch fysicus-audioloog | Universitair Audiol= ogisch Centrum | VU medisch centrum Afdeling KNO-Audiologie | EMGO Institute for Health and Care Research Secretariaat Audiologie, Postbus 7057, 1007 MB Amsterdam T (020) 444 09 69 | F (020) 444 09 83 | E c.smits@xxxxxxxx<mailto:c.smits@xxxxxxxx= mc.nl> | W www.AC-VUmc.nl<http://www.AC-VUmc.nl> www.CI-VUmc.nl<http://www= .CI-VUmc.nl> Disclaimer Deze e-mail is vertrouwelijk en alleen bestemd voor de geadresseerde. Als d= eze e-mail niet voor u bestemd is, wordt u verzocht dit aan de afzender te = melden, het bericht niet verder te verspreiden en direct te vernietigen. VU= medisch centrum staat niet in voor de juiste en volledige overbrenging van= de inhoud van deze e-mail. Van: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx= LL.CA] Namens Pierre Divenyi Verzonden: Saturday, 25 January, 2014 17:33 Aan: AUDITORY@xxxxxxxx Onderwerp: Re: [AUDITORY] Reference for typical SNRs is public spaces I agree with Bill except for one (crucial) assumption: in a cocktail-party = situation the noise is not stationary (although, as Jont Allen once suggest= ed, adding talkers to the babble will make it approach stationarity). So, t= he 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<mailto:dicklyon@xxxxxxxx>> Reply-To: "Richard F. Lyon" <dicklyon@xxxxxxxx<mailto:dicklyon@xxxxxxxx>> Date: Friday, January 24, 2014 at 10:16 PM To: <AUDITORY@xxxxxxxx<mailto: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 particul= ar listener, above the noise. Other people trying to communicate to differ= ent listeners make noise for this one. The SNR is therefore roughly consta= nt, 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<mailto:= Bill_Woods@xxxxxxxx>> wrote: Dear List, Since we're assuming Andy is asking about speech-to-noise ratio when referr= ing to SNR in public spaces, I wondered if the question couldn't be answere= d by back-of-the-envelope calculations using some assumptions and articulat= ion index theory (AI). It turned out there was quite a long list of assumptions behind the calcula= tion (see below), but the resultant simple calculation yielded a SNR of 0.5= dB, which is quite in line with the values other posters have indicated ma= y actually be present. Two other facts became apparent as I did this, howev= er, and further motivate my posting. First, the long list of assumptions makes apparent the long list of influen= ces on the SNR in such a situation. These influences need to be characteriz= ed in any attempt to generalize from SNR measurements in a given scenario, = a fact other posters have alluded to. Second, it is important to note that much work has been done recently to mo= del or empirically characterize these influences on speech intelligibility,= and 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 lapt= op computers. The implication is that it should not be very difficult to de= termine a reasonably-accurate distribution of SNRs over wide variation in t= he assumed listening scenario without any measurements. Cheers, Bill 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.stark= eyresearch.com> | map<http://maps.google.com/maps?q=3D2150+Shattuck+Avenue,= +Berkeley,+CA+94704&hl=3Den&ll=3D37.869941,-122.268219&spn=3D0.028152,0.038= 066&sll=3D37.86923,-122.273197&sspn=3D0.056305,0.076132&z=3D15> | email<mai= lto:william_woods@xxxxxxxx> The assumptions are: 1. Talkers have no hearing loss and no cognitive loss. 2. The talkers are facing each other and speaking in their "mother ton= gue". 3. We know the percent-correct (%C) targeted by the talkers and it is = less than 100% (it's a challenging environment). 4. We know the nature of the speech in such a conversation, from a low= -context vs. high-context perspective. 5. The talkers are within their critical distance (i.e., ignore reverb= eration of talkers' 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 speech= generates the equivalent of an "internal" wideband binaural SNR improvemen= t of ~1.0 dB over monaural listening. 11. Overall level is not too high (i.e., no "roll-over" effect for intelli= gibility has occurred). 12. We're not including lip reading. These assumptions allow one to, first, determine the AI needed to achieve t= he assumed target %C given the assumed type of speech, and, second, determi= ne the SNR required with the assumed spectral shapes to obtain that AI. For instance, assuming talkers want 95%C with "unfamiliar sentences" then u= sing the polynomial fits from Sherbecoe and Studebaker (JASA 1990) of the A= NSI S3.5-1969 transfer functions between AI and %C, our talkers would need = an AI of 0.45. If we assume the noise and speech have the same long-term sp= ectral shape then the SNR can be determined from (SNR+12)/30=3D0.45 (stayin= g with the 1969 AI method), yielding SNR =3D 1.5 dB. Subtracting the binau= ral SNR improvement yields 0.5 dB. From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx= ILL.CA] On Behalf Of Andy Sabin Sent: Wednesday, January 22, 2014 9:53 AM To: AUDITORY@xxxxxxxx<mailto:AUDITORY@xxxxxxxx> Subject: Reference for typical SNRs is public spaces Hi List, Can anyone point me to a reference showing SNRs that are typically observed= in public spaces (e.g., restaurants, bars ...etc)? I can find this info fo= r overall SPL, but am having a hard time finding it for SNR. Thanks Andy Sabin --_000_5801ADC15F4A8D4CAC8F4B3195FA6327EF3B322BSPMXMBX32vumcnl_ 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:x=3D"urn:schemas-microsoft-com:office:excel" xmlns:p=3D"urn:schemas-m= icrosoft-com:office:powerpoint" xmlns:a=3D"urn:schemas-microsoft-com:office= :access" xmlns:dt=3D"uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:s=3D"= uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:rs=3D"urn:schemas-microsof= t-com:rowset" xmlns:z=3D"#RowsetSchema" xmlns:b=3D"urn:schemas-microsoft-co= m:office:publisher" xmlns:ss=3D"urn:schemas-microsoft-com:office:spreadshee= t" xmlns:c=3D"urn:schemas-microsoft-com:office:component:spreadsheet" xmlns= :odc=3D"urn:schemas-microsoft-com:office:odc" xmlns:oa=3D"urn:schemas-micro= soft-com:office:activation" xmlns:html=3D"http://www.w3.org/TR/REC-html40" = xmlns:q=3D"http://schemas.xmlsoap.org/soap/envelope/" xmlns:rtc=3D"http://m= icrosoft.com/officenet/conferencing" xmlns:D=3D"DAV:" xmlns:Repl=3D"http://= schemas.microsoft.com/repl/" xmlns:mt=3D"http://schemas.microsoft.com/share= point/soap/meetings/" xmlns:x2=3D"http://schemas.microsoft.com/office/excel= /2003/xml" xmlns:ppda=3D"http://www.passport.com/NameSpace.xsd" xmlns:ois= =3D"http://schemas.microsoft.com/sharepoint/soap/ois/" xmlns:dir=3D"http://= schemas.microsoft.com/sharepoint/soap/directory/" xmlns:ds=3D"http://www.w3= .org/2000/09/xmldsig#" xmlns:dsp=3D"http://schemas.microsoft.com/sharepoint= /dsp" xmlns:udc=3D"http://schemas.microsoft.com/data/udc" xmlns:xsd=3D"http= ://www.w3.org/2001/XMLSchema" xmlns:sub=3D"http://schemas.microsoft.com/sha= repoint/soap/2002/1/alerts/" xmlns:ec=3D"http://www.w3.org/2001/04/xmlenc#"= xmlns:sp=3D"http://schemas.microsoft.com/sharepoint/" xmlns:sps=3D"http://= schemas.microsoft.com/sharepoint/soap/" xmlns:xsi=3D"http://www.w3.org/2001= /XMLSchema-instance" xmlns:udcs=3D"http://schemas.microsoft.com/data/udc/so= ap" xmlns:udcxf=3D"http://schemas.microsoft.com/data/udc/xmlfile" xmlns:udc= p2p=3D"http://schemas.microsoft.com/data/udc/parttopart" xmlns:m=3D"http://= schemas.microsoft.com/office/2004/12/omml" xmlns:st=3D"&#1;" 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=3D"Generator" content=3D"Microsoft Word 12 (filtered medium)"> <style> <!-- /* Font Definitions */ @xxxxxxxx {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4;} @xxxxxxxx {font-family:Tahoma; panose-1:2 11 6 4 3 5 4 4 2 4;} @xxxxxxxx {font-family:Verdana; panose-1:2 11 6 4 3 5 4 4 2 4;} @xxxxxxxx {font-family:ver;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0cm; margin-bottom:.0001pt; font-size:12.0pt; font-family:"Times New Roman","serif";} a:link, span.MsoHyperlink {mso-style-priority:99; color:blue; text-decoration:underline;} a:visited, span.MsoHyperlinkFollowed {mso-style-priority:99; color:purple; text-decoration:underline;} span.E-mailStijl17 {mso-style-type:personal-reply; font-family:"Calibri","sans-serif"; color:#1F497D;} .MsoChpDefault {mso-style-type:export-only; font-size:10.0pt;} @xxxxxxxx Section1 {size:612.0pt 792.0pt; margin:70.85pt 70.85pt 70.85pt 70.85pt;} div.Section1 {page:Section1;} /* List Definitions */ @xxxxxxxx l0 {mso-list-id:751002726; mso-list-template-ids:-1183955402;} ol {margin-bottom:0cm;} ul {margin-bottom:0cm;} --> </style><!--[if gte mso 9]><xml> <o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" /> </xml><![endif]--><!--[if gte mso 9]><xml> <o:shapelayout v:ext=3D"edit"> <o:idmap v:ext=3D"edit" data=3D"1" /> </o:shapelayout></xml><![endif]--> </head> <body lang=3D"EN-US" link=3D"blue" vlink=3D"purple" style=3D"word-wrap: bre= ak-word; -webkit-nbsp-mode: space;-webkit-line-break: after-white-space"> <div class=3D"Section1"> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D">We used a method to determine the relation between AI/SII an= d SNR for fluctuating noise in a way quite similar to the way Bill proposed= (Smits and Festen, 2013). We found a different relationship between SII and SNR for two-band = speech modulated noise compared to steady-state noise (a 2-dB increase in S= NR for fluctuating noise gives almost the same increase in SII as a 1-dB in= crease in SNR for steady-state noise). This method works well in lab settings but I think the uncertainties are t= oo large to make reliable predictions for real-life situations. The effects= of speaking style, speech material, talker etc on percentage correct (the = speech recognition function) are large and the (backward) calculations give large uncertainties in SNR esti= mates. In situations with fluctuating noise the use of the steady-state noi= se relationship between SII and SNR could give large errors. With interferi= ng talkers (informational masking) things get even more complicated.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D">But, coming back to the question, normal-hearing listeners c= an follow most conversations in public spaces with some difficulty (often i= n situations with multitalker babble which is very similar to stationairy noise). Thus, SNRs around 0-5 = dB SNR sounds plausible...<o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D">Cas Smits<o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D">Smits C, Festen JM. The interpretation of speech reception t= hreshold data in normal-hearing and hearing-impaired listeners: II. Fluctua= ting noise.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D">J Acoust Soc Am. 2013 May;133(5):3004-15<o:p></o:p></span></= p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal" style=3D"line-height:12.0pt;mso-line-height-rule:exa= ctly"><b><span style=3D"font-size:8.0pt;font-family:&quot;Verdana&quot;,&qu= ot;sans-serif&quot;;color:#10137D">dr.ir. J.C.M. (Cas) Smits, klinisch fysi= cus-audioloog</span></b><b><span style=3D"font-size:8.0pt;font-family:ver;c= olor:#10137D">&nbsp;</span></b><b><span style=3D"font-size:8.0pt;font-famil= y:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#10137D">| Universitair Audiologisch Centrum | VU medisch centrum</span></b><span sty= le=3D"font-size: 8.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:black"> </span><span style=3D"font-size:8.0pt;color:#10137D"><br> </span><span style=3D"font-size:8.0pt;font-family:&quot;Verdana&quot;,&quot= ;sans-serif&quot;; color:black">Afdeling KNO-Audiologie | EMGO Institute for Health and Care R= esearch</span><span style=3D"color:black"><o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"line-height:12.0pt;mso-line-height-rule:exa= ctly"><span lang=3D"NL" style=3D"font-size:8.0pt;font-family:&quot;Verdana&= quot;,&quot;sans-serif&quot;;color:black">Secretariaat Audiologie, Postbus = 7057, 1007 MB Amsterdam<br> </span><b><span lang=3D"NL" style=3D"font-size:8.0pt;font-family:&quot;Verd= ana&quot;,&quot;sans-serif&quot;; color:#E5053A">T</span></b><span lang=3D"NL" style=3D"font-size:8.0pt;font-= family: &quot;Verdana&quot;,&quot;sans-serif&quot;;color:black"> (020) 444 09 69 |&= nbsp;</span><b><span lang=3D"NL" style=3D"font-size:8.0pt;font-family:&quot= ;Verdana&quot;,&quot;sans-serif&quot;;color:#E5053A">F</span></b><span lang= =3D"NL" style=3D"font-size:8.0pt;font-family:&quot;Verdana&quot;,&quot;sans= -serif&quot;;color:black"> (020) 444 09 83 |&nbsp;</span><b><span lang=3D"NL" style=3D"font-size:8.0p= t; font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#E5053A">E</sp= an></b><span lang=3D"NL" style=3D"font-size:8.0pt;font-family:&quot;Verdana= &quot;,&quot;sans-serif&quot;;color:black">&nbsp;</span><span style=3D"colo= r:#10137D"><a href=3D"mailto:c.smits@xxxxxxxx"><span lang=3D"NL" style=3D"fo= nt-size:8.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;">c.smi= ts@xxxxxxxx</span></a></span><span lang=3D"NL" style=3D"font-size:8.0pt;font= -family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:black">&nbsp;| </span><b><span lang=3D"NL" style=3D"font-size:8.0pt;font-family:&quot;Verd= ana&quot;,&quot;sans-serif&quot;; color:#E5053A">W</span></b><span lang=3D"NL" style=3D"font-size:8.0pt;font-= family: &quot;Verdana&quot;,&quot;sans-serif&quot;;color:black"> </span><span style=3D"color:#10137D"><a href=3D"http://www.AC-VUmc.nl"><spa= n lang=3D"NL" style=3D"font-size:8.0pt;font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;">www.AC-VUmc.nl</span></a></span= ><span lang=3D"NL" style=3D"font-size:8.0pt;font-family:&quot;Verdana&quot;= ,&quot;sans-serif&quot;;color:black">&nbsp;</span><span lang=3D"NL" style= =3D"font-size:8.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;= color:#E5053A">&nbsp;</span><span style=3D"font-size:8.0pt;font-family:&quo= t;Verdana&quot;,&quot;sans-serif&quot;;color:purple"><a href=3D"http://www.= CI-VUmc.nl"><span lang=3D"NL">www.CI-VUmc.nl</span></a></span><span lang=3D= "NL" style=3D"color:#10137D"><o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"line-height:12.0pt;mso-line-height-rule:exa= ctly"><span lang=3D"NL" style=3D"color:#10137D">&nbsp;<o:p></o:p></span></p= > <p class=3D"MsoNormal"><span lang=3D"NL" style=3D"color:#10137D">&nbsp;<o:p= ></o:p></span></p> <p class=3D"MsoNormal"><u><span lang=3D"NL" style=3D"font-size:9.0pt;color:= gray">Disclaimer<o:p></o:p></span></u></p> <p class=3D"MsoNormal"><span lang=3D"NL" style=3D"font-size:9.0pt;color:gra= y">Deze e-mail is vertrouwelijk en alleen bestemd voor de geadresseerde. Al= s deze e-mail niet voor u bestemd is, wordt u verzocht dit aan de afzender = te melden, het bericht niet verder te verspreiden en direct te vernietigen. VU medisch centrum staat niet in voo= r de juiste en volledige overbrenging van de inhoud van deze e-mail.</span>= <span lang=3D"NL"><o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"NL" style=3D"font-size:11.0pt;font-fam= ily:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"NL" style=3D"font-size:11.0pt;font-fam= ily:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"NL" style=3D"font-size:11.0pt;font-fam= ily:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:#1F497D"><o:p>&nbsp;</o:p></span></p> <div> <div style=3D"border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm = 0cm 0cm"> <p class=3D"MsoNormal"><b><span lang=3D"NL" style=3D"font-size:10.0pt;font-= family:&quot;Tahoma&quot;,&quot;sans-serif&quot;">Van:</span></b><span lang= =3D"NL" style=3D"font-size:10.0pt;font-family:&quot;Tahoma&quot;,&quot;sans= -serif&quot;"> AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx= LISTS.MCGILL.CA] <b>Namens </b>Pierre Divenyi<br> <b>Verzonden:</b> Saturday, 25 January, 2014 17:33<br> <b>Aan:</b> AUDITORY@xxxxxxxx<br> <b>Onderwerp:</b> Re: [AUDITORY] Reference for typical SNRs is public space= s<o:p></o:p></span></p> </div> </div> <p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p> <div> <p class=3D"MsoNormal"><span style=3D"font-size:10.5pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:black">I agree with Bill except for one (crucial) assumption: in a co= cktail-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.<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-size:10.5pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:black"><o:p>&nbsp;</o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-size:10.5pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:black">-Pierre<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-size:10.5pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:black"><o:p>&nbsp;</o:p></span></p> </div> <div style=3D"border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm = 0cm 0cm"> <p class=3D"MsoNormal"><b><span style=3D"font-size:11.0pt;font-family:&quot= ;Calibri&quot;,&quot;sans-serif&quot;; color:black">From: </span></b><span style=3D"font-size:11.0pt;font-family:&quot;Calibri&quot;,= &quot;sans-serif&quot;; color:black">&quot;Richard F. Lyon&quot; &lt;<a href=3D"mailto:dicklyon@xxxxxxxx= .ORG">dicklyon@xxxxxxxx</a>&gt;<br> <b>Reply-To: </b>&quot;Richard F. Lyon&quot; &lt;<a href=3D"mailto:dicklyon= @xxxxxxxx">dicklyon@xxxxxxxx</a>&gt;<br> <b>Date: </b>Friday, January 24, 2014 at 10:16 PM<br> <b>To: </b>&lt;<a href=3D"mailto:AUDITORY@xxxxxxxx">AUDITORY@xxxxxxxx= CGILL.CA</a>&gt;<br> <b>Subject: </b>Re: [AUDITORY] Reference for typical SNRs is public spaces<= o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-size:10.5pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:black"><o:p>&nbsp;</o:p></span></p> </div> <div> <div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><span style=3D"font-s= ize:10.5pt; font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black">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.&nbsp; The SNR that he estimates is not &quot;in the= space&quot;, but rather &quot;at the ears of the listener&quot; when the t= alker is trying to communicate to that particular listener, above the noise= .&nbsp; Other people trying to communicate to different listeners make noise for this one.&nbsp; The SNR is therefore roughly constant, some= where near 0 dB, almost anywhere that's not too quiet.<o:p></o:p></span></p= > </div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><span style=3D"font-s= ize:10.5pt; font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black">For me,= it's a little higher, after I make people speak up.<br> <br> Dick<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><span style=3D"font-s= ize:10.5pt; font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:p>&n= bsp;</o:p></span></p> <div> <p class=3D"MsoNormal"><span style=3D"font-size:10.5pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:black">On Fri, Jan 24, 2014 at 1:51 PM, Bill Woods &lt;<a href=3D"mai= lto:Bill_Woods@xxxxxxxx" target=3D"_blank">Bill_Woods@xxxxxxxx</a>&gt= ; wrote:<o:p></o:p></span></p> <div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">Dear List,<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">Since we&#8217;re assuming Andy is asking ab= out speech-to-noise ratio when referring to SNR in public spaces, I wondere= d if the question couldn&#8217;t be answered by back-of-the-envelope calculations using some assumptions and articulation index theory (AI).&nb= sp; <o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">&nbsp;<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">It turned out there was quite a long list of= assumptions behind the calculation (see below), but the resultant simple c= alculation yielded 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. <o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">&nbsp;<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">First, the long list of assumptions makes ap= parent the long list of influences on the SNR in such a situation. These in= fluences need to be characterized in any attempt to generalize from SNR measurements in a given scenario, a fact other posters have allud= ed to.<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">&nbsp;<o:p></o:p></span></p> </div> <div style=3D"margin-bottom:12.0pt"> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">Second, it is important to note that much wo= rk has been done recently to model or empirically characterize these influe= nces on speech intelligibility, and 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 implicati= on is that it should not be very difficult to determine a reasonably-accura= te distribution of SNRs over wide variation in the assumed listening scenario without any measurements. <o:p= ></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">Cheers,<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">Bill<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <table class=3D"MsoNormalTable" border=3D"0" cellpadding=3D"0" width=3D"377= " style=3D"width:282.75pt; margin-left:5.4pt"> <tbody> <tr> <td style=3D"padding:.75pt .75pt .75pt .75pt"> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Arial&quot;,&quot;s= ans-serif&quot;;color:#17365D">Bill Woods, PhD<br> </span><span style=3D"font-size:10.0pt;font-family:&quot;Arial&quot;,&quot;= sans-serif&quot;; color:#595959">Principal Research Scientist&nbsp;|&nbsp;Starkey Hearing R= esearch Center<br> 2150 Shattuck Ave.&nbsp;|&nbsp;Suite 408&nbsp;|&nbsp;Berkeley,&nbsp;CA&nbsp= ;94704-1345<br> T:&nbsp;<a href=3D"tel:510-845-4876%C2%A0x%C2%A014" target=3D"_blank">510-8= 45-4876&nbsp;x&nbsp;14</a> </span><o:p></o:p></p> </td> </tr> <tr> <td style=3D"padding:.75pt .75pt .75pt .75pt"> <p class=3D"MsoNormal"><a href=3D"http://www.starkey.com/" target=3D"_blank= "><span style=3D"font-size:10.0pt;font-family:&quot;Arial&quot;,&quot;sans-= serif&quot;">starkey.com</span></a><span style=3D"font-size:10.0pt;font-fam= ily:&quot;Arial&quot;,&quot;sans-serif&quot;;color:#0000F6">&nbsp;</span><s= pan style=3D"font-size:10.0pt;font-family:&quot;Arial&quot;,&quot;sans-seri= f&quot;;color:#595959">|</span><span style=3D"font-size:10.0pt;font-family:= &quot;Arial&quot;,&quot;sans-serif&quot;;color:#0000F6">&nbsp;</span><a hre= f=3D"http://www.starkeyresearch.com" target=3D"_blank"><span style=3D"font-= size: 10.0pt;font-family:&quot;Arial&quot;,&quot;sans-serif&quot;">starkeyresea= rch.com</span></a><span style=3D"font-size:10.0pt;font-family:&quot;Arial&q= uot;,&quot;sans-serif&quot;;color:#0000F6">&nbsp;</span><span style=3D"font= -size:10.0pt;font-family:&quot;Arial&quot;,&quot;sans-serif&quot;;color:#59= 5959">|</span><span style=3D"font-size:10.0pt;font-family:&quot;Arial&quot;= ,&quot;sans-serif&quot;;color:#0000F6">&nbsp;</span><a href=3D"http://maps.= google.com/maps?q=3D2150&#43;Shattuck&#43;Avenue,&#43;Berkeley,&#43;CA&#43;= 94704&amp;hl=3Den&amp;ll=3D37.869941,-122.268219&amp;spn=3D0.028152,0.03806= 6&amp;sll=3D37.86923,-122.273197&amp;sspn=3D0.056305,0.076132&amp;z=3D15" t= arget=3D"_blank"><span style=3D"font-size:10.0pt;font-family:&quot;Arial&qu= ot;,&quot;sans-serif&quot;">map</span></a><span style=3D"font-size:10.0pt;f= ont-family:&quot;Arial&quot;,&quot;sans-serif&quot;;color:#0000F6">&nbsp;</= span><span style=3D"font-size:10.0pt;font-family:&quot;Arial&quot;,&quot;sa= ns-serif&quot;;color:#595959">|</span><span style=3D"font-size:10.0pt;font-= family:&quot;Arial&quot;,&quot;sans-serif&quot;;color:#0000F6">&nbsp;</span= ><a href=3D"mailto:william_woods@xxxxxxxx" target=3D"_blank"><span style= =3D"font-size:10.0pt;font-family:&quot;Arial&quot;,&quot;sans-serif&quot;">= email</span></a><o:p></o:p></p> </td> </tr> <tr> <td style=3D"padding:.75pt .75pt .75pt .75pt"></td> </tr> <tr> <td style=3D"padding:.75pt .75pt .75pt .75pt"></td> </tr> </tbody> </table> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">The assumptions are:<o:p></o:p></span></p> </div> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">1.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">Talkers have no hearing loss and no cognitive loss.<o:p></o:p>= </span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">2.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">The talkers are facing each other and speaking in their &#8220= ;mother tongue&#8221;.<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">3.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">We know the percent-correct (%C) targeted by the talkers and i= t is less than 100% (it&#8217;s a challenging environment).<o:p></o:p></spa= n></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">4.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">We know the nature of the speech in such a conversation, from = a low-context vs. high-context perspective.<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">5.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">The talkers are within their critical distance (i.e., ignore r= everberation of talkers&#8217; speech).<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">6.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">We know the long-term spectral shape of speech at the eardrums= .<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">7.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">We know the long-term spectral shape of noise at the eardrums.= <o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">8.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">The noise is stationary.<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">9.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp;&nbs= p;&nbsp;&nbsp;&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;; color:black">The noise is diffuse.<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">10.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;;color:black">The diffuse noise in combination wit= h diotic direct-wave target speech generates the equivalent of an &#8220;in= ternal&#8221; wideband binaural SNR improvement of ~1.0 dB over monaural listening.<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">11.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;;color:black">Overall level is not too high (i.e.,= no &#8220;roll-over&#8221; effect for intelligibility has occurred).<o:p><= /o:p></span></p> <p class=3D"MsoNormal" style=3D"mso-margin-top-alt:auto;mso-margin-bottom-a= lt:auto; margin-left:0cm;text-indent:-18.0pt;mso-list:l0 level1 lfo1"> <![if !supportLists]><span style=3D"font-family:&quot;Calibri&quot;,&quot;s= ans-serif&quot;;color:black"><span style=3D"mso-list: Ignore">12.<span style=3D"font:7.0pt &quot;Times New Roman&quot;">&nbsp; </span></span></span><![endif]><span style=3D"font-family:&quot;Calibri&quo= t;,&quot;sans-serif&quot;;color:black">We&#8217;re not including lip readin= g.<o:p></o:p></span></p> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">These assumptions allow one to, first, deter= mine the AI 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.<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">&nbsp;<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"font-family:&quot;Calibri&quot;,&quot= ;sans-serif&quot;;color:black">For instance, assuming talkers want 95%C wit= h &#8220;unfamiliar sentences&#8221; then using the polynomial fits from Sh= erbecoe 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 assume the = noise and speech have the same long-term spectral shape then the SNR can be= determined from (SNR&#43;12)/30=3D0.45 (staying with the 1969 AI method), = yielding SNR =3D 1.5 dB.&nbsp; Subtracting the binaural SNR improvement yields 0.5 dB.&nbsp; <o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <div> <p class=3D"MsoNormal"><b><span style=3D"font-size:10.0pt;font-family:&quot= ;Tahoma&quot;,&quot;sans-serif&quot;; color:black">From:</span></b><span style=3D"font-size:10.0pt;font-family:&q= uot;Tahoma&quot;,&quot;sans-serif&quot;; color:black"> AUDITORY - Research in Auditory Perception [<a href=3D"mailto= :AUDITORY@xxxxxxxx" target=3D"_blank">mailto:AUDITORY@xxxxxxxx= A</a>] <b>On Behalf Of </b>Andy Sabin<o:p></o:p></span></p> </div> <p class=3D"MsoNormal"><b><span style=3D"font-size:10.0pt;font-family:&quot= ;Tahoma&quot;,&quot;sans-serif&quot;; color:black">Sent:</span></b><span style=3D"font-size:10.0pt;font-family:&q= uot;Tahoma&quot;,&quot;sans-serif&quot;; color:black"> Wednesday, January 22, 2014 9:53 AM<o:p></o:p></span></p> <div> <p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Ta= homa&quot;,&quot;sans-serif&quot;; color:black"><br> <b>To:</b> <a href=3D"mailto:AUDITORY@xxxxxxxx" target=3D"_blank">AU= DITORY@xxxxxxxx</a><br> <b>Subject:</b> Reference for typical SNRs is public spaces<o:p></o:p></spa= n></p> </div> </div> <div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">Hi List,&nbsp;</span><sp= an style=3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:bl= ack"><o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">Can anyone point me to a= reference showing SNRs that are typically observed in public spaces (e.g.,= restaurants, bars ...etc)? I can find this info for overall SPL, but am ha= ving a hard time finding it for SNR.&nbsp;</span><span style=3D"font-family= :&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black"><o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">Thanks</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">Andy Sabin</span><span s= tyle=3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"= ><o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span style=3D"color:black">&nbsp;</span><span style= =3D"font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black"><o:= p></o:p></span></p> </div> </div> </div> </div> <p class=3D"MsoNormal"><span style=3D"font-size:10.5pt;font-family:&quot;Ca= libri&quot;,&quot;sans-serif&quot;; color:black"><o:p>&nbsp;</o:p></span></p> </div> </div> </body> </html> --_000_5801ADC15F4A8D4CAC8F4B3195FA6327EF3B322BSPMXMBX32vumcnl_--


This message came from the mail archive
/var/www/postings/2014/
maintained by:
DAn Ellis <dpwe@ee.columbia.edu>
Electrical Engineering Dept., Columbia University