<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* 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;}
p
{mso-style-priority:99;
margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0cm;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-GB" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Randy<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">We did a lot of tests on this in 2000 at Soundcraft to prove just how many bits we needed at the bottom end, so as to use the rest at the top end to give us
an overload margin. Everyone involved could hear at least 8.5 to 10dB below the noise level, and some about 14-15 dB down, which corresponds well with Brian’s 18.5 bits. This was done using the best at the time products from both AKM and Cirrus Logic, and
there was no perceptible difference between the two so it was unlikely that people were noticing some distortion or other artefact and thinking it was the signal.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">As for the test equipment, signals at greater than 20dB below the noise floor were easily visible in the noise on the Audio Precision, the gold standard for
audio test equipment.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I’m afraid there’s no associated AES paper on this work because company policy at the time was not to publish papers or patents, the company founder once saying
“I was both surprised and delighted to be awarded an AES Fellowship, particularly because I’ve never presented any papers on my subject”
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Mike<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Synth-diy [mailto:synth-diy-bounces@synth-diy.org]
<b>On Behalf Of </b>Randy Dawson<br>
<b>Sent:</b> 16 February 2021 06:57<br>
<b>To:</b> Brian Willoughby<br>
<b>Cc:</b> synth-diy@synth-diy.org<br>
<b>Subject:</b> Re: [sdiy] CD sound quality evolution<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:black">Thanks, Brian, for your great audio insight, but I will stick with my original assertion that 16 bit is OK.<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:black">I offer a challenge you and AES to provide any thing about audio that is beyond this, and actually perceptible by even the Golden Ear customer.<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:black">I am a Senior member of IEEE,
<a href="mailto:rdawson@ieee.org">rdawson@ieee.org</a><o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:black">Randy<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:black"><o:p> </o:p></span></p>
</div>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="5" width="98%" align="center">
</div>
<div id="divRplyFwdMsg">
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black"> Brian Willoughby <brianw@audiobanshee.com><br>
<b>Sent:</b> Monday, February 15, 2021 10:16 PM<br>
<b>To:</b> Randy Dawson <rdawson16@hotmail.com><br>
<b>Cc:</b> synth-diy@synth-diy.org <synth-diy@synth-diy.org><br>
<b>Subject:</b> Re: [sdiy] CD sound quality evolution</span> <o:p></o:p></p>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:11.0pt">Human perception of sound does not work in plain black and white. Frequency response is not flat, sounds at one frequency can mask another; our brains are even so slow that sounds
which occur later in time can actually mask sounds that occur earlier in time.<br>
<br>
Bit depth is not a cliff where sounds completely disappear below -96 dBFS limit of 16-bit audio. It's way more complex than that. When comparing what's audible to the numbers, there's not a clear line between two distinct opposites.<br>
<br>
On the one hand, the human brain can discern sounds well below whatever quantization depth is chosen. This is how 24-bit mastered CD actually sounds better than 16-bit mastering. The 16-bit noise is still all there - it's simply piled into frequency bands that
our brains cannot detect quite so well.<br>
<br>
On the other hand, the nature of the quantization itself determines whether it is audible. Correlated quantization noise is easily audible, and quite objectionable. Random dither almost disappears - not to test equipment, but to our perception - because we're
constantly ignoring Gaussian noise sources in nature to discern quieter sounds that might be important.<br>
<br>
AES experts have pointed out that the best audiophile listening setup can achieve only about 18.5 bits of signal to noise. I guess that puts it around 112 dB S/N.<br>
<br>
So, yeah, depending upon the kinds of noise that will be picked up even with shielded cables, it is indeed still possible to hear better than 16-bit audio.<br>
<br>
You'll never hear all 24 bits, though. The equipment will have more analog noise than quantization noise, although correlated quantization noise will still be audible despite the louder analog noise. Under the best conditions, though, the quantization noise
can become inaudible and you're still left with less S/N than the 24-bit DAC handle theoretically produce. This is a blessing in disguise, because all 24-bit DAC chips cannot even hold a steady value due to the massive filter processing going on.<br>
<br>
Brian Willoughby<br>
<br>
<br>
On Feb 15, 2021, at 21:31, Randy Dawson wrote:<br>
> You can't get lower than 16 bits in your home-lab environment with a 1V audio typical signal transport and shielded cables around the room you are working in.<br>
> For 16 bits:<br>
> 2 ^ 16 = 65536<br>
> 1V / 65536 = .00001525878 V (LSB Voltage change)<br>
> <br>
> I challenge the Golden Ears to toggle this 16 bit LSB above; in their audio chain, from any source in any way, and claim it is audible, or measurable in any audio equipment.<br>
> <br>
> Randy<br>
> KF7CJW<br>
> <a href="mailto:rdawson@ieee.org">rdawson@ieee.org</a><o:p></o:p></span></p>
</div>
</div>
</div>
</body>
</html>