klaus filip

i was looking into the shepard.help patch of the CNMAT package.

setting the amount of partials in that patch does not work correctly.

if you set it higher than 8, this will result into astronomical frequencies.

looking into the javascript shepard.js by adrian freed left me stumped

but i guess a smart change in this loop could help:

        freq = f* Math.pow(pi,j) ;

        l[((j+n-offset)%n)*2] = f0*freq; //this is where the frequencies of the list are set

        l[((j+n-offset)%n)*2+1] = Math.pow(10,0.075*(80*0.5*(1+Math.cos(3.14159265358979*(f+j-n/2)/((n+pi)/2)))-80)); // Shepard used a raised cosine

i also tried to tweak the variable pi (which appears to be a constant of 2),

it helped a bit, then the effect limps at offset changes.

i attach a simple testing patch and the original shepard.js

Written by Adrian Freed, The Center for New Music and Audio Technologies,

Permission to use, copy, modify, distribute, and distribute modified versions

of this software and its documentation without fee and without a signed

licensing agreement, is hereby granted, provided that the above copyright

notice, this paragraph and the following two paragraphs appear in all copies,

IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,

SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING

OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS

BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED

HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE

MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

DESCRIPTION: Shepard tone (infinite glissando) synthesis

SVN_REVISION: $LastChangedRevision: 618 $

        l[((j+n-offset)%n)*2] = f0*freq;

hi there
i was looking into the shepard.help patch of the CNMAT package.
setting the amount of partials in that patch does not work correctly.
if you set it higher than 8, this will result into astronomical frequencies.

looking into the javascript shepard.js by adrian freed left me stumped
but i guess a smart change in this loop could help:
for(var j=0;j
	{
		freq = f* Math.pow(pi,j) ;
		l[((j+n-offset)%n)*2] = f0*freq; //this is where the frequencies of the list are set
		l[((j+n-offset)%n)*2+1] = Math.pow(10,0.075*(80*0.5*(1+Math.cos(3.14159265358979*(f+j-n/2)/((n+pi)/2)))-80)); // Shepard used a raised cosine
	}

i also tried to tweak the variable pi (which appears to be a constant of 2),
it helped a bit, then the effect limps at offset changes.

please help
i attach a simple testing patch and the original shepard.js

Written by Adrian Freed, The Center for New Music and Audio Technologies,
University of California, Berkeley.  Copyright (c) 2005-6, The Regents of
the University of California (Regents).  

Permission to use, copy, modify, distribute, and distribute modified versions
of this software and its documentation without fee and without a signed
licensing agreement, is hereby granted, provided that the above copyright
notice, this paragraph and the following two paragraphs appear in all copies,
modifications, and distributions.

IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
NAME: Shepard
DESCRIPTION: Shepard tone (infinite glissando) synthesis
AUTHORS: Adrian Freed
COPYRIGHT_YEARS: 2005-6
SVN_REVISION: $LastChangedRevision: 618 $
VERSION 1.0: First release
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

var n=8; // number of partials
var f0=80; // frequency f0 in Hz
var f=1; // normalized frequency
var offset=0;
function bang()
{
	msg_float(1.0594633);
}
function msg_float(ff)
{
	f *=ff;
	var pi = Math.pow(1.0594633,12);
//	post(pi);
	var l=new Array();

	while(f
	{
		f = f-1+pi;
		offset = (offset+n-1)%n;
	}
	while(f>pi )
	{
		f = f-pi+1;
		offset = (offset+1)%n;

	var freq;
	for(var j=0;j
	{
		freq = f* Math.pow(pi,j) ;
		l[((j+n-offset)%n)*2] = f0*freq;
		l[((j+n-offset)%n)*2+1] = Math.pow(10,0.075*(80*0.5*(1+Math.cos(3.14159265358979*(f+j-n/2)/((n+pi)/2)))-80)); // Shepard used a raised cosine
	}
	outlet(0,l);
}

function pitch(f)
{
	if(f>0 && f
		f0 = f;
}
function partials(p)
{
	if(p>0 && p
		n = p;
}
