(Neil Waterman )


Subject: 
From:    Neil Waterman  <neil.waterman@xxxxxxxx>
Date:    Mon, 18 Jan 2010 11:19:05 -0500
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

--Apple-Mail-3--90979574 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hello all, I was pointed to this list from the friendly folk over at the SurSound (surround sound list) as my question will hopefully sit more comfortably with the expertise here, but as a newbie here I'll preface my question with a preemptive apology if I am at all off- topic for the list focus. Here's my question: I have been attempting to track down any research directed toward human perception of delay in local sidetone. Specifically I am trying to find any work investigating perception of very short delays when using fully digital systems that return sidetone via the digital signal chain (mic --> A/D --> processing system --> D/A --> headset). An example might be the use of a fully digital communications system within an aircraft, where the processing system is the aircraft communications equipment. When the crew talk on a radio, they expect to hear themselves via sidetone (this confirms the radio is working for one thing). Although searching high and low, I have been unable to find anything useful regarding tolerance to delay. It seems most of what I can find refers to VoIP systems, where the latency issues appear to be much longer than those I am considering. In the limited work I can, find most dismiss delays in the sub-20mS as being below human perception, however I have evidential proof that this is plainly wrong. If anyone has any suggestions for research that covers sidetone delay in the sub-20mS region I would be extremely grateful. Thanks in advance for any and all input. - Neil --Apple-Mail-3--90979574 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=US-ASCII <html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; = -webkit-line-break: after-white-space; "><div><span = class=3D"Apple-style-span" style=3D"border-collapse: separate; color: = rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: = normal; font-variant: normal; font-weight: normal; letter-spacing: = normal; line-height: normal; orphans: 2; text-align: auto; text-indent: = 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: = 0px; -webkit-border-horizontal-spacing: 0px; = -webkit-border-vertical-spacing: 0px; = -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: = auto; -webkit-text-stroke-width: 0; "><span class=3D"Apple-style-span" = style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: = Helvetica; font-size: 12px; font-style: normal; font-variant: normal; = font-weight: normal; letter-spacing: normal; line-height: normal; = orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; = widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; = -webkit-border-vertical-spacing: 0px; = -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: = auto; -webkit-text-stroke-width: 0px; "><div>Hello = all,</div><div><br></div><div>I was pointed to this list from the = friendly folk over at the SurSound (surround sound list) as my question = will hopefully sit more comfortably with the expertise here, but as a = newbie here I'll preface my question with a preemptive apology if I am = at all off-topic for the list focus.</div><div><br></div><div>Here's my = question:</div><div><br></div><div><div style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">I have been = attempting to track down any research directed toward human perception = of delay in local sidetone. Specifically I am trying to find any work = investigating perception of very short delays when using fully digital = systems that return sidetone via the digital signal chain (mic --&gt; = A/D --&gt; processing system --&gt; D/A --&gt; headset).</div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; min-height: 14px; "><br></div><div style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">An = example might be the use of a fully digital communications system within = an aircraft, where the processing system is the aircraft communications = equipment. When the crew talk on a radio, they expect to hear themselves = via sidetone (this confirms the radio is working for one = thing).&nbsp;</div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">Although searching high and low, I have been unable = to find anything useful regarding tolerance to delay. It seems most of = what I can find refers to VoIP systems, where the latency issues appear = to be much longer than those I am considering.</div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; min-height: 14px; "><br></div><div style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">In the = limited work I can, find most dismiss delays in the sub-20mS as being = below human perception, however I have evidential proof that this is = plainly wrong. If anyone has any suggestions for research that covers = sidetone delay in the sub-20mS region I would be extremely = grateful.</div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">Thanks in advance for any and all input.</div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><br></div><div style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">- = Neil</div></div></span><br class=3D"Apple-interchange-newline"></span><br = class=3D"Apple-interchange-newline"> </div><br></body></html>= --Apple-Mail-3--90979574--


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