Re: Reference for typical SNRs is public spaces ("Hornsby, Benjamin Wade Young" )

Subject: Re: Reference for typical SNRs is public spaces From: "Hornsby, Benjamin Wade Young" <ben.hornsby@xxxxxxxx> Date: Thu, 23 Jan 2014 14:49:32 +0000 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY> --_000_4E3E190AD76D794590065A186A2F3B7924193DITSHCWNEM104dsvan_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hello, This is an interesting question and I agree I'm not sure we have definitive= answer. My interpretation of the Pearsons data is that SNRs in the environ= ments they tested were generally quite positive (+4 to +14 dB inside and ou= tside homes, hospitals and department stores; all based on A-weighted measu= res) except for measures made on trains and in aircraft where average SNRs = dropped to -1 to -2 dB (see their Table II). This seems to be somewhat cons= istent with the measures described by Karolina, if I'm recalling the poster= correctly. To me this seems to make sense because communicating in very noisy settings= (e.g., BG noise levels >70-75 dB) would require the individual to either 1= ) speak at very high vocal efforts (try speaking at a level of 70-75 dBA -1= meter from the microphone for any length of time. I find I have to concent= rate and work hard to keep that level) or 2) be very close to the listener = to create SNRs that are reasonable for carrying on a "conversation". The Pe= arsons data suggests people move closer rather than speak at levels above 7= 0 dBA. So to Andy's original question "...SNRs that are typically observed in publ= ic spaces (e.g., restaurants, bars ...etc)..." I guess you would have to de= cide what is "typical"? How much of the day are you in restaurants and bars= (where the SNRs may be quite poor) versus other settings where the SNRs ar= e generally much more favorable. Ben From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx= ILL.CA] On Behalf Of John Culling Sent: Thursday, January 23, 2014 4:44 AM To: AUDITORY@xxxxxxxx Subject: Re: Reference for typical SNRs is public spaces Hi Andy. This is a very tricky question. I am not aware of any definitive data that = really addresses the issue adequately. Laboratory studies tend to use single sound sources in anechoic conditions. The auditory system copes very well in these conditions. The results indica= te that listeners can cope with very low SNRs (e.g. -10 dB for spatialised spe= ech- shaped noise interference, and lower for speech interferers). Moreover, som= e studies have used several interferers (e.g. Peissig and Kollmeier '97, Hawl= ey et al. '04), and shown a gradual elevation in SRT with increasing numbers of inter= ferers. Simulating a more complex scene, like a restaurant with multiple interferer= s and reverberation produces progressive degradation, though. We have been simulating up to eight interfering voices from a variety of speakers with r= everb based on real-room binaural room impulse responses. SRTs are around -2 to -= 3 dB with eigth interfering voices. I haven't begun to write this work up yet= , but the results are not disimilar to those from a cruder preliminary study publ= ished here. Culling, J. F. (2013). "Energetic and informational masking in a simulated = restaurant environment" in Moore, B. C. J., Carlyon, R. P., and Gockel, H.,= Patterson, R. D. and Winter, I. M.. (eds) Basic Aspects of Hearing: Physio= logy and Perception (Springer, New York) There remain limitations to this approach, of course. The technique remains dependent on standard target speech materials (IEEE/Harvard sentences) that are not very typical of normal conversation - particularly lacking a conversational context. It is also unclear whether 50% keyword intelligibil= ity is a tolerable level of comprehension for conversation. Karolina's study has other limitations. If I remember correctly, the materi= al was recorded from hearing impaired individuals, who may avoid the more severe listening conditions into which normally hearing people thrust themselves. Also, the method of establishing the SNR from the recordings would probably become impossible below a certain SNR, as it relies on a researcher judging from the recordings alone whether or not target speech is present. Noise level is collected from epochs without target speech, and speech level is derived by subtraction. Nonetheless, both approaches indicate that real-world SNRs are unlikely to be very near -10 dB, but be somewhere around 0 dB. Karolina's work suggests a bit above, mine a bit below. I guess what is really needed is for pairs of interlocutors to be wired up = with close microphones at the mouth (to establish reliably who is talking when) and at their ears, and then to go out for the night and try to produce norm= al speaking and listening behaviour. Perhaps after a few nights of this they would habituate to all the kit, and produce data that will get us closer to= a true answer. John From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx= ILL.CA] On Behalf Of Andy Sabin Sent: 22 January 2014 17:53 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_4E3E190AD76D794590065A186A2F3B7924193DITSHCWNEM104dsvan_ 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=3D"Generator" content=3D"Microsoft Word 14 (filtered medium)"> <style></style> </head> <body lang=3D"EN-US" link=3D"#0563C1" vlink=3D"#954F72"> <div class=3D"WordSection1"> Hello,<o:p></o:p><= /p> This is an interesting qu= estion and I agree I’m not sure we have definitive answer. My interpr= etation of the Pearsons data is that SNRs in the environments they tested were generally quite positive (+4 to +14 dB inside and= outside homes, hospitals and department stores; all based on A-weighted me= asures) except for measures made on trains and in aircraft where average SN= Rs dropped to -1 to -2 dB (see their Table II). This seems to be somewhat consistent with the measures described by K= arolina, if I’m recalling the poster correctly.<o:p></o:p> To me this seems to make = sense because communicating in very noisy settings (e.g., BG noise levels &= gt;70-75 dB) would require the individual to either 1) speak at very high vocal efforts (try speaking at a level of 70-75 dBA -1 meter = from the microphone for any length of time. I find I have to concentrate an= d work hard to keep that level) or 2) be very close to the listener to crea= te SNRs that are reasonable for carrying on a “conversation”. The Pearsons data suggests peopl= e move closer rather than speak at levels above 70 dBA.<o:p></o:p></= p> <o:p> </o:p><= /p> So to Andy’s origin= al question “…SNRs that are typically observed in public= spaces (e.g., restaurants, bars ...etc)…” I guess you would have to decide what is “= typical”? How much of the day are you in restaurants and bars (where = the SNRs may be quite poor) versus other settings where the SNRs are generally much more favorable.<o:p></o:p> <o:p> </o:p><= /p> Ben<o:p></o:p> <o:p> </o:p><= /p> <o:p> </o:p><= /p> <div> <div style=3D"border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in = 0in 0in"> From: AUDITORY= - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx On Behalf Of John Culling Sent: Thursday, January 23, 2014 4:44 AM To: AUDITORY@xxxxxxxx Subject: Re: Reference for typical SNRs is public spaces<o:p></o:p><= /span> </div> </div> <o:p> </o:p> Hi Andy.<o:p></o:p></spa= n> <o:p> </o:p>= This is a very tricky qu= estion. I am not aware of any definitive data that really<o:p></o:p>= addresses the issue adeq= uately. <o:p></o:p> <o:p> </o:p>= Laboratory studies tend = to use single sound sources in anechoic conditions.<o:p></o:p> The auditory system cope= s very well in these conditions. The results indicate <o:p></o:p> that listeners can cope = with very low SNRs (e.g. -10 dB for spatialised speech-<o:p></o:p></= p> shaped noise interferenc= e, and lower for speech interferers). Moreover, some <o:p></o:p> studies have used severa= l interferers (e.g. Peissig and Kollmeier '97, Hawley et al. <o:p></o:p> '04), and shown a gradua= l elevation in SRT with increasing numbers of interferers.<o:p></o:p></span= > Simulating a more comple= x scene, like a restaurant with multiple interferers<o:p></o:p> and reverberation produc= es progressive degradation, though. We have been<o:p></o:p> simulating up to eight i= nterfering voices from a variety of speakers with reverb<o:p></o:p><= /p> based on real-room binau= ral room impulse responses. SRTs are around -2 to -3<o:p></o:p> dB with eigth interferin= g voices. I haven't begun to write this work up yet, but <o:p></o:p> the results are not disi= milar to those from a cruder preliminary study published<o:p></o:p><= /p> here.<o:p></o:p><= /p> <o:p> </o:p>= Culling, J. F. (2013). “Energetic and informational masking in a simulated resta= urant environment” in Moore, B. C. J., Carlyon, R. P., and Gockel, H.= , Patterson, R. D. and Winter, I. M.. (eds) Basic Aspects of Hearing: Physiology and Perception (Springer, New Y= ork)<o:p></o:p> <o:p> </o:p> There remain limitations to this approach= , of course. The technique remains<o:p></o:p> dependent on standard target speech mater= ials (IEEE/Harvard sentences)<o:p></o:p> that are not very typical of normal conve= rsation - particularly lacking a <o:p></o:p> conversational context. It is also unclea= r whether 50% keyword intelligibility<o:p></o:p> is a tolerable level of comprehension for= conversation.<o:p></o:p> <o:p> </o:p> Karolina's study has other limitations. I= f I remember correctly, the material<o:p></o:p> was recorded from hearing impaired indivi= duals, who may avoid the more<o:p></o:p> severe listening conditions into which no= rmally hearing people thrust <o:p></o:p> themselves. Also, the method of establish= ing the SNR from the recordings<o:p></o:p> would probably become impossible below a = certain SNR, as it relies on<o:p></o:p> a researcher judging from the recordings = alone whether or not target <o:p></o:p> speech is present. Noise level is collect= ed from epochs without target<o:p></o:p> speech, and speech level is derived by su= btraction.<o:p></o:p> <o:p> </o:p> Nonetheless, both approaches indicate tha= t real-world SNRs are unlikely<o:p></o:p> to be very near -10 dB, but be somewhere = around 0 dB. Karolina's work<o:p></o:p> suggests a bit above, mine a bit below.<o= :p></o:p> <o:p> </o:p> I guess what is really needed is for pair= s of interlocutors to be wired up with <o:p></o:p> close microphones at the mouth (to establ= ish reliably who is talking when) <o:p></o:p> and at their ears, and then to go out for= the night and try to produce normal<o:p></o:p> speaking and listening behaviour. Perhaps= after a few nights of this they <o:p></o:p> would habituate to all the kit, and produ= ce data that will get us closer to a <o:p></o:p> true answer. <o:p></o:p> <o:p> </o:p> John<o:p></o:p> <o:p> </o:p>= From: AUDITO= RY - Research in Auditory Perception [<a href=3D"mailto:AUDITORY@xxxxxxxx= LL.CA">mailto:AUDITORY@xxxxxxxx</a>] On Behalf Of Andy Sabin Sent: 22 January 2014 17:53 To: <a href=3D"mailto:AUDITORY@xxxxxxxx">AUDITORY@xxxxxxxx= L.CA</a> Subject: Reference for typical SNRs is public spaces<o:p></o:p></spa= n> <o:p> </o:p> <div> Hi List, <o:p></o:p></span= > <div> <o:p> </o:p> </div> <div> Can anyone point me to a refere= nce showing SNRs that are typically observed in public spaces (e.g., restau= rants, bars ...etc)? I can find this info for overall SPL, but am having a = hard time finding it for SNR. <o:p></o:p> </div> <div> <o:p> </o:p> </div> <div> Thanks<o:p></o:p> </div> <div> Andy Sabin<o:p></o:p></p= > </div> </div> </div> </body> </html> --_000_4E3E190AD76D794590065A186A2F3B7924193DITSHCWNEM104dsvan_--

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