<html><body><font face="Helvetica">Well, if you consider nature as everything in the material universe, then I suppose so.<br><br>Ian<br><br><br>Sent from XFINITY Connect Mobile App<br><br><br>------ Original Message ------<br><br>From: Michael E Caloroso<br>To: Ian Fritz<br>Cc: Tom Wiltshire, synth-diy@synth-diy.org<br>Sent: September 15, 2017 at 5:37 PM<br>Subject: Re: [sdiy] Walsh Functions/EN S-008<br><br>The alloys that transistors are made of come from nature, do they not?<br><br>MC<br><br>On Sep 14, 2017, at 2:58 PM, ijfritz@comcast.net wrote:<br><br>Well, neither are transistors. :-)<br><br>On 9/15/17, Ian Fritz <ijfritz@comcast.net> wrote:<br>> Tom --<br>><br>> Thanks for the discussion. I can tell from your response that I haven't<br>> explained myself well enough. Here goes for another try.<br>><br>> Multiple pulsed or stepped waveforms have different spectra and sounds<br>> from traditional waveforms. (If you are happy with the MacMoog<br>> waveforms, then fine.) The new spectral features extend throughout the<br>> audio range. The ones at the lower end give timbers that are<br>> fundamentally different from traditional ones. The ones at high<br>> frequencies are strong, sure. But ultimately they roll off at 6 dB /<br>> Oct, just like the traditional Saw and Pulse waveforms. Obviously, you<br>> can use LP filtering to reduce the brightness, just as you might on the<br>> traditional waveforms. For some analytics on typical double-pulse<br>> waveforms, please refer to Bernie's EN #228, available online:<br>> http://electronotes.netfirms.com/free.htm<br>><br>> >>><br>> What’s wrong with trying to transform a flute into a clarinet? One has<br>> hardly any harmonics, and the other has a few more, but neither have<br>> many. If you don’t like that example, pick one with less. It doesn’t<br>> matter. The point is only: why limit yourself to waveforms with a lot of<br>> harmonic content? Why is that better?<br>> <<<<br>><br>> I think you may have misunderstood what I was trying to say. I asked<br>> why you would use a Walsh generator to morph between low harmonic<br>> content waveforms, when there are simpler methods available. What<br>> simple methods, you ask? Well, dynamic mixing of the two waves is<br>> probably the easiest method, at least conceptually. For your<br>> flute-clarinet question, you can morph between Tri and Square waves by<br>> amplifying and clipping the Tri. Morphing Tri to Saw is a bit trickier,<br>> but a few years back I figured out how to do this using a saturating<br>> negative impedance converter. A fairly detailed explanation, with<br>> representative sound clips, is on my website:<br>> http://ijfritz.byethost4.com/sy_cir10.htm<br>> I actually have dedicated versions of this circuit on two of my VCOs.<br>> The advantage of morphing vs mixing is there are no steps, so driving<br>> other waveshapers goes more smoothly.<br>><br>> >>><br>> The more interesting stuff for me is the subtler changes in timbre that<br>> can be achieved, that give the ear interest but don’t “wow!” it with<br>> unusual gimmicks.<br>> <<<<br>><br>> Actually, with a greater variety of waveform choices you have WAY MORE<br>> scope along these lines. I did a lot of work years ago synthesizing<br>> quasi-realistic sounds. I've never put all this up, but short<br>> representative clips are here:<br>> http://ijfritz.byethost4.com/sy_close.htm<br>> Almost all these sounds were generated using the Double Pulse Waveform<br>> Generator or the DoubleDeka 10-step VCO. (At least if "the high quickly<br>> wears off and these are sounds that get tired fast", the clips are short.)<br>><br>> There are many examples of sounds from pulse/step waveform sources on my<br>> website and you tube channel.<br>> http://ijfritz.byethost4.com/ website index<br>> http://ijfritz.byethost4.com/sy_cir8.htm 5 Pulser Waveshaper Project<br>> http://ijfritz.byethost4.com/sy_cir5.htm Double Pulse Waveform generator<br>> http://ijfritz.byethost4.com/sy_cir6.htm Wavolver<br>> http://ijfritz.byethost4.com/sy_cir10.htm SNICster<br>> http://ijfritz.byethost4.com/MiscProj/DD.htm DoubleDeka<br>> https://www.youtube.com/user/frijitz001 Demos of commercialized modules<br>><br>> There are also numerous comments and videos from other users of these<br>> modules on the electro-music and muff's forums and on you tube. This<br>> post is already too long, so I won't elaborate on all these.<br>><br>> >>><br>> For this reason I’ve been looking at the way shifting the phase of the<br>> harmonics in a waveform affects the crossfade between one waveform and<br>> another - suddenly something that was previously a simple linear<br>> crossfade becomes non-linear and more interesting, not in a ‘grab you by<br>> the ears and shake you” way but rather something more subtle. This for<br>> me is more where I’d like to be.<br>> <<<<br>><br>> I have no idea what this means. But by all means, please get back to us<br>> when you actually have something to show.<br>><br>> Ian<br>><br>><br>> On 9/14/2017 5:45 PM, Tom Wiltshire wrote:<br>>> Hi Ian,<br>>><br>>> Thanks for that report. It’s very interesting. “Smooth, even if fairly<br>>> extreme” is something I might need to hear to understand. Yes, I<br>>> understand that there will be a fairly strong fundamental in any waveform<br>>> like this - even if that’s mainly perceptual rather than actual. It’s<br>>> still what we hear. Morphing between two low-harmonic waveforms has all<br>>> kinds of uses. What’s wrong with trying to transform a flute into a<br>>> clarinet? One has hardly any harmonics, and the other has a few more, but<br>>> neither have many. If you don’t like that example, pick one with less. It<br>>> doesn’t matter. The point is only: why limit yourself to waveforms with a<br>>> lot of harmonic content? Why is that better?<br>>><br>>> I don’t understand what you mean by "why would you do it this way instead<br>>> of by simple means?”. If it's important, please explain. I’m sorry I<br>>> didn’t get it first time.<br>>><br>>> In many ways, I don’t think “extreme wave shaping” is my direction of<br>>> travel. Extreme results are very quickly perceived as artificial, and in<br>>> my view that makes them a “quick fix” - perhaps they’re exciting for a<br>>> moment, but the high quickly wears off and these are sounds that get tired<br>>> fast. The more interesting stuff for me is the subtler changes in timbre<br>>> that can be achieved, that give the ear interest but don’t “wow!” it with<br>>> unusual gimmicks. For this reason I’ve been looking at the way shifting<br>>> the phase of the harmonics in a waveform affects the crossfade between one<br>>> waveform and another - suddenly something that was previously a simple<br>>> linear crossfade becomes non-linear and more interesting, not in a ‘grab<br>>> you by the ears and shake you” way but rather something more subtle. This<br>>> for me is more where I’d like to be.<br>>><br>>> Please understand I’m not trying to dissuade Pete or anyone else from<br>>> doing their own experiments and coming to their own conclusions. One of<br>>> the great things is that there’s a lot of different places to go and a lot<br>>> of potential things to discover. It’d get dull fast if we all went in the<br>>> same direction!<br>>><br>>> Regards,<br>>> Tom<br>>><br>>>> On 14 Sep 2017, at 22:55, ijfritz@comcast.net wrote:<br>>>><br>>>> Hmmm ... not sure about all that. I have a VCO that has ten-step<br>>>> waveform generators. I can make timbre changes by shoving the sliders<br>>>> around. To my ear the changes sound smooth, even if fairly extreme.<br>>>> Same thing with the extreme waveforms in my 5 Pulser waveshaper.<br>>>> Remember, you almost always hear a strong fundamental frequency when<br>>>> doing this kind of morphing. (Unless you deliberately suppress it.) But<br>>>> tell me, why would you want to morph between two low-harmonic content<br>>>> waveforms anyway? I mean why would you do it this way instead of by<br>>>> simple means?<br>>>><br>>>> I think it would be quite interesting to listen to dynamically changing<br>>>> Walsh-generated waveforms. There could well be interesting dynamic<br>>>> "phasy-ness". Or interesting initial note transients. Or cool<br>>>> audio-frequency timbre modulation effects.<br>>>><br>>>> Carry on Pete! I've been working on extreme waveshaping for over thirty<br>>>> years, and several modules based on this work have been successfully<br>>>> commercialized. I think you will almost certainly get some interesting<br>>>> results. And of course it would be easy to generate these dynamic<br>>>> waveforms with simple code or simulations.<br>>>><br>>>> Ian<br>>>><br>>>><br>>>><br>>>><br>>>> Sent from XFINITY Connect Mobile App<br>>>><br>>>><br>>>> ------ Original Message ------<br>>>><br>>>> From: Tom Wiltshire<br>>>> To: Pete Hartman<br>>>> Cc: synth-diy@synth-diy.org DIY<br>>>> Sent: September 14, 2017 at 5:02 AM<br>>>> Subject: Re: [sdiy] Walsh Functions/EN S-008<br>>>><br>>>> Isn’t the trouble with Walsh function synthesis that each coefficient<br>>>> controls a complex waveform with a whole fistful of harmonics? While it’s<br>>>> possible to carefully mix Walsh functions to get smooth-sounding<br>>>> waveforms by cancelling out higher harmonics, any minor tweak to the<br>>>> coefficient values is going to introduce large abrupt edges and<br>>>> significant high frequencies. That makes waveform morphing pretty much<br>>>> bound to go from A via buzziness to B.<br>>>> Basing things on sine waves is so much simpler in many ways, despite<br>>>> Walsh functions being much easier to generate.<br>>>><br>>>> Tom<br>>>><br>>>> ==================<br>>>> Electric Druid<br>>>> Synth & Stompbox DIY<br>>>> ==================<br>>>><br>>>>> On 14 Sep 2017, at 05:38, Pete Hartman <pete.hartman@gmail.com> wrote:<br>>>>><br>>>>> There are a wide range of folks on here, including some who've been<br>>>>> doing this stuff since ElectroNotes was young :) so I'm hoping maybe<br>>>>> someone can help.<br>>>>><br>>>>> I was perusing old issues, in particular #16, which came with a<br>>>>> supplement S-008 on Walsh functions. These functions were also<br>>>>> discussed somewhat in #16 and a couple subsequent issues. However I<br>>>>> don't have a copy of S-008, and after asking Bernie about it, he has so<br>>>>> far been unable to locate a copy.<br>>>>><br>>>>> I suppose if I had my head more fully around the math of Fourier series<br>>>>> it might not be so difficult for me, but I'm not grasping the entire<br>>>>> idea of using the Walsh functions for waveform generation, and I'm kind<br>>>>> of interested. My thought is that while, as Bernie points out in #16<br>>>>> and his paper for AES, the generated waveforms themselves aren't<br>>>>> particularly notable, modulating the coefficients of the different<br>>>>> waveforms might sound different than other types of waveform modulation.<br>>>>> I'm interested to play around with it in any case. Big picture wise, I<br>>>>> see the parallel to Fourier and understand the concept, I'm just not<br>>>>> following the nature of the coefficients to generate specific waveform<br>>>>> types.<br>>>>><br>>>>> I got the impression from the references to the supplement that it might<br>>>>> help get me over the block I'm having. But not having it myself, and so<br>>>>> far unable to get one from the source (despite his much appreciated<br>>>>> search for same) the question turns to whether any of y'all out there<br>>>>> might have a copy of S-008? If so, and if we can get Bernie's blessing<br>>>>> (and probably send him a copy too), I'd be interested in some form of it<br>>>>> that I could read.<br>>>>><br>>>>> Thanks!<br>>>>><br>>>>> Pete<br>>>>> _______________________________________________<br>>>>> Synth-diy mailing list<br>>>>> Synth-diy@synth-diy.org<br>>>>> http://synth-diy.org/mailman/listinfo/synth-diy<br>>>><br>>>><br>>>> _______________________________________________<br>>>> Synth-diy mailing list<br>>>> Synth-diy@synth-diy.org<br>>>> http://synth-diy.org/mailman/listinfo/synth-diy<br>>><br>>><br>><br>><br>> --<br>> ijfritz.byethost4.com<br>> _______________________________________________<br>> Synth-diy mailing list<br>> Synth-diy@synth-diy.org<br>> http://synth-diy.org/mailman/listinfo/synth-diy<br>><br></font></body></html>