Subject: Re: Characteristics of a diffuse sound field From: Eric Benjamin <ebenj@xxxxxxxx> Date: Thu, 24 Jan 2013 23:59:53 -0800 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>---106228746-777629810-1359100793=:13095 Content-Type: text/plain; charset=us-ascii It's interesting that you ask the question "what constitutes a 'diffuse sound field' " in terms of how a layman would perceive it. I've tried getting an answer to that question on a number of occasions, with very little success. Usually I don't get an answer. When I do get an answer, it's always couched in terms of light and something on the order of "It means that I can't see the source". Which is, in fact, a bit helpful. Have a look at "A simulated diffuse field for in situ microphone measurements" http://asadl.org/jasa/resource/1/jasman/v118/i3/p1858_s3?bypassSSO=1 and further information at: http://www.cjs-labs.com/sitebuildercontent/sitebuilderfiles/SimDiffuse.pdf I've used variations on this technique with good success. I verify the diffuseness of the generated field by rotating a cardioid microphone through the range of directions and then plotting the polar patterns at various frequencies. Eric Benjamin ________________________________ From: Phil McCandless <pmccand@xxxxxxxx> To: AUDITORY@xxxxxxxx Sent: Thu, January 24, 2013 9:51:17 PM Subject: Characteristics of a diffuse sound field All, I am designing a manikin head for recording and am interested in HRTF's. I have run into a bit of a shortfall on information relating to what constitutes a "diffuse sound field". I would like someone to answer this question from two audience viewpoints.... 1) the layman. How is one to find a suitable "room" for creating a reverberant environment such as a closet, empty classroom, cafeteria, or empty basketball stadium to conduct informal, but effective HRTF studies using manikin dummy models? 2) the scientist. What is the definition or characteristics of a truly diffuse sound field useful for experimentation with HRTF's? Thanks in advance Phil Mc Cand.le.ss ---106228746-777629810-1359100793=:13095 Content-Type: text/html; charset=us-ascii <html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial, helvetica, sans-serif;font-size:10pt"><div><font face="arial, helvetica, sans-serif" size="2">It's interesting that you ask the question "what constitutes a 'diffuse sound field' " in terms of how a layman would perceive it. I've tried getting an answer to that question on a number of occasions, with very little success. Usually I don't get an answer. When I do get an answer, it's always couched in terms of light and something on the order of "It means that I can't see the source". Which is, in fact, a bit helpful.</font></div><div><font face="arial, helvetica, sans-serif" size="2"><br></font></div><div style="font-family: arial, helvetica, sans-serif; font-size: 10pt;">Have a look at "<span style="font-size: small; font-family: Verdana; line-height: 28px;">A simulated diffuse field for </span><em class="emphitalic" style="font-size: small; font-family: Verdana; line-height: 28px;">in situ</em><span style="font-size: small; font-family: Verdana; line-height: 28px;"> </span><span style="font-size: small; font-family: Verdana; line-height: 28px;">microphone measurements</span><span style="color: black; font-size: 10pt;">"</span></div><div><font face="arial, helvetica, sans-serif" size="2"><span><a target="_blank" href="http://asadl.org/jasa/resource/1/jasman/v118/i3/p1858_s3?bypassSSO=1">http://asadl.org/jasa/resource/1/jasman/v118/i3/p1858_s3?bypassSSO=1</a></span></font></div><div style="color: black; font-family: arial, helvetica, sans-serif; font-size: 10pt;"><br></div><div style="color: black; font-family: arial, helvetica, sans-serif; font-size: 10pt;">and further information at:</div><div><font face="arial, helvetica, sans-serif" size="2"><span><a target="_blank" href="http://www.cjs-labs.com/sitebuildercontent/sitebuilderfiles/SimDiffuse.pdf">http://www.cjs-labs.com/sitebuildercontent/sitebuilderfiles/SimDiffuse.pdf</a></span></font></div><div><font face="arial, helvetica, sans-serif" size="2"><br></font></div><div><font face="arial, helvetica, sans-serif" size="2">I've used variations on this technique with good success. I verify the diffuseness of the generated field by rotating a cardioid microphone through the range of directions and then plotting the polar patterns at various frequencies.</font></div><div><font face="arial, helvetica, sans-serif" size="2"><br></font></div><div><font face="arial, helvetica, sans-serif" size="2">Eric Benjamin</font></div><div><font face="arial, helvetica, sans-serif" size="2"><br></font></div><div><font face="arial, helvetica, sans-serif" size="2"><br></font><div style="color: black; font-family: 'times new roman', 'new york', times, serif; font-size: 12pt;"><font size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Phil McCandless <pmccand@xxxxxxxx><br><b><span style="font-weight: bold;">To:</span></b> AUDITORY@xxxxxxxx<br><b><span style="font-weight: bold;">Sent:</span></b> Thu, January 24, 2013 9:51:17 PM<br><b><span style="font-weight: bold;">Subject:</span></b> Characteristics of a diffuse sound field<br></font><br><table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top" style="font:inherit;">All,<br><br>I am designing a manikin head for recording and am interested in HRTF's. I have run into a bit of a shortfall on information relating to what constitutes a "diffuse sound field". <br><br>I would like someone to answer this question from two audience viewpoints....<br><br>1) the layman. How is one to find a suitable "room" for creating a reverberant environment such as a closet, empty classroom, cafeteria, or empty basketball stadium to conduct informal, but effective HRTF studies using manikin dummy models? <br><br>2) the scientist. What is the definition or characteristics of a truly diffuse sound field useful for experimentation with HRTF's?<br><br>Thanks in advance<br><br>Phil Mc Cand.le.ss<br><br><br> <br></td></tr></tbody></table></div></div><div style="color: black; font-family: arial, helvetica, sans-serif; font-size: 10pt; position: fixed;"></div> </div></body></html> ---106228746-777629810-1359100793=:13095--