[sdiy] Walsh Functions/EN S-008

Tom Wiltshire tom at electricdruid.net
Thu Sep 14 13:00:36 CEST 2017


Isn’t the trouble with Walsh function synthesis that each coefficient controls a complex waveform with a whole fistful of harmonics? While it’s possible to carefully mix Walsh functions to get smooth-sounding waveforms by cancelling out higher harmonics, any minor tweak to the coefficient values is going to introduce large abrupt edges and significant high frequencies. That makes waveform morphing pretty much bound to go from A via buzziness to B.
Basing things on sine waves is so much simpler in many ways, despite Walsh functions being much easier to generate.

Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================

> On 14 Sep 2017, at 05:38, Pete Hartman <pete.hartman at gmail.com> wrote:
> 
> There are a wide range of folks on here, including some who've been doing this stuff since ElectroNotes was young :) so I'm hoping maybe someone can help.
> 
> I was perusing old issues, in particular #16, which came with a supplement S-008 on Walsh functions.  These functions were also discussed somewhat in #16 and a couple subsequent issues.  However I don't have a copy of S-008, and after asking Bernie about it, he has so far been unable to locate a copy.
> 
> I suppose if I had my head more fully around the math of Fourier series it might not be so difficult for me, but I'm not grasping the entire idea of using the Walsh functions for waveform generation, and I'm kind of interested.  My thought is that while, as Bernie points out in #16 and his paper for AES, the generated waveforms themselves aren't particularly notable, modulating the coefficients of the different waveforms might sound different than other types of waveform modulation.  I'm interested to play around with it in any case.  Big picture wise, I see the parallel to Fourier and understand the concept, I'm just not following the nature of the coefficients to generate specific waveform types.
> 
> I got the impression from the references to the supplement that it might help get me over the block I'm having.  But not having it myself, and so far unable to get one from the source (despite his much appreciated search for same) the question turns to whether any of y'all out there might have a copy of S-008?  If so, and if we can get Bernie's blessing (and probably send him a copy too), I'd be interested in some form of it that I could read.
> 
> Thanks!
> 
> Pete
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