<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Hi,</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Thank you for the example re: polyshape , square wave. I am surprised to see that fractions vs. decimals for amps in the float-vector makes a difference in the chebyshev coefficients.<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
(partials->polynomial (float-vector 1 1 3 1/3 5 1/5 7 1/7 9 1/9 ))
<div>;(0.0 1.0 0.0 -7.999999999999999 0.0 35.2 0.0 -54.85714285714286 0.0 28.44444444444444)</div>
<div><br>
</div>
<div>(with-sound (:srate 48000 :channels 1 :play #t) </div>
<div> (let ((gen (make-polyshape 100.0 :coeffs #r(0.0 1.0 0.0 -7.999999999999999 0.0 35.2 0.0 -54.85714285714286 0.0 28.44444444444444) ))</div>
<div> )</div>
<div> (do ((i 0 (+ i 1)))</div>
<div> ((= i 88200))</div>
<span> (outa i (* .75 (polyshape gen 1.0 ))))))</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span><br>
</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span>When trying to plug the coefficents back into make-polyshape, I get a different wave shape, which looks more like a triangle-ish wave instead of the square:<br>
</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="font-size: 20pt;">^^^^^^</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="font-size: 20pt;"></span><span></span>I believe this is where I'm stuck, trying to empirically understand how the chebyshev coefficient numbers work for additive synthesis. I thought the problem might be normalization or order of coefficients?
Still not sure where I'm going wrong.</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Any help, advice much appreciated.</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Regards,</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Jim<br>
</div>
<div>
<div id="appendonsend"></div>
<div style="font-family:Calibri,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<hr tabindex="-1" style="display:inline-block; width:98%">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> cmdist-bounces@ccrma.Stanford.EDU <cmdist-bounces@ccrma.Stanford.EDU> on behalf of cmdist-request@ccrma.Stanford.EDU <cmdist-request@ccrma.Stanford.EDU><br>
<b>Sent:</b> Tuesday, October 26, 2021 9:00 AM<br>
<b>To:</b> cmdist@ccrma.Stanford.EDU <cmdist@ccrma.Stanford.EDU><br>
<b>Subject:</b> Cmdist Digest, Vol 161, Issue 11</font>
<div> </div>
</div>
<div class="BodyFragment"><font size="2"><span style="font-size:11pt">
<div class="PlainText">Send Cmdist mailing list submissions to<br>
cmdist@ccrma.stanford.edu<br>
<br>
To subscribe or unsubscribe via the World Wide Web, visit<br>
<a href="https://cm-mail.stanford.edu/mailman/listinfo/cmdist">https://cm-mail.stanford.edu/mailman/listinfo/cmdist</a><br>
or, via email, send a message with subject or body 'help' to<br>
cmdist-request@ccrma.stanford.edu<br>
<br>
You can reach the person managing the list at<br>
cmdist-owner@ccrma.stanford.edu<br>
<br>
When replying, please edit your Subject line so it is more specific<br>
than "Re: Contents of Cmdist digest..."<br>
<br>
<br>
Today's Topics:<br>
<br>
1. poly questions (James Hearon)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Tue, 26 Oct 2021 17:40:43 +0000<br>
From: James Hearon <j_hearon@hotmail.com><br>
To: "cmdist@ccrma.Stanford.EDU" <cmdist@ccrma.Stanford.EDU><br>
Subject: [CM] poly questions<br>
Message-ID:<br>
<DM6PR10MB2537AB5EB7D8EC958CBB12C2E5849@DM6PR10MB2537.namprd10.prod.outlook.com><br>
<br>
Content-Type: text/plain; charset="iso-8859-1"<br>
<br>
Hi,<br>
Trying to get an understanding of all the interesting aspects of polywave in snd, and chebyshev polynomials, coefficients etc. I was trying to get a squarish wave from the coefficients but failing.<br>
Also tried partials->polynomial, and normalize-partials with same result. Wondering what I'm misunderstanding about how you would employ the coefficients for a typical float-vector of partials, and amps for say a square wave?<br>
<br>
(with-sound (:srate 48000 :channels 1 :play #t)<br>
(let ((gen (make-polyshape 100.0 :coeffs (partials->polynomial (float-vector 1 1 3 .33 5 .2 7 .142 9 0.111)) ))<br>
)<br>
(do ((i 0 (+ i 1)))<br>
((= i 88200))<br>
(outa i (* .75 (polyshape gen 1.0 ))))))<br>
<br>
Also, if I can ask more than one question per email, how do you go about using the generators:<br>
<br>
mus-chebyshev-tu-sum x t-coeffs u-coeffs<br>
mus-chebyshev-t-sum x t-coeffs<br>
mus-chebyshev-u-sum x u-coeffs<br>
<br>
I couldn't seem to locate an ex. for those, but I did see the c code in clm.c which is interesting.<br>
Thank you,<br>
Regards,<br>
Jim<br>
<br>
-------------- next part --------------<br>
An HTML attachment was scrubbed...<br>
URL: <<a href="https://cm-mail.stanford.edu/pipermail/cmdist/attachments/20211026/e9ebab85/attachment-0001.html">https://cm-mail.stanford.edu/pipermail/cmdist/attachments/20211026/e9ebab85/attachment-0001.html</a>><br>
<br>
------------------------------<br>
<br>
_______________________________________________<br>
Cmdist mailing list<br>
Cmdist@ccrma.stanford.edu<br>
<a href="https://cm-mail.stanford.edu/mailman/listinfo/cmdist">https://cm-mail.stanford.edu/mailman/listinfo/cmdist</a><br>
<br>
<br>
End of Cmdist Digest, Vol 161, Issue 11<br>
***************************************<br>
</div>
</span></font></div>
</div>
</body>
</html>