I have come to a point where it looks like it is behaving like a VCF but creating artefact, dropping frequency, etc… so it might sound nice.
I am sharing this here, and I’ll let you know once I get a chance to breadboard it.
" https://tinyurl.com/2ry6z5w5 (link to falstad simulation)
Cut-off level, input level both have an impact of the wave shape.
And it also self oscillate but not as as sine wave.
Ho, and if you see something that doesn’t look right please shout.
Looks interesting though I have a hard time figuring out what’s going on. (Am I the only person who thinks Falstad looks butt ugly and a mess to follow? And I went to look at Klein’s filter but there’s no complete schematic in the video that I can find, and in the description below is… a link to a Falstad simulation.) Is the red trace a CV? Or is that the input signal and we’re seeing a ton of some high frequency being added to it? (Not sure of the time scale.) What is the difference between your first three images?
In your pictures I don’t see anything that looks to me like wave folding going on, but then the wave folder is on the resonance path not the output path, so… who knows that to expect? Something bizarre apparently!
Hey, there is a link (1st post) to the simulation itslef it you want to have a better look.
The red trace is the input signal.
If you feed it a sine wave, you can guess the wave folding effect and some resonnance on top of it.
But, falstad is not the best and I have no clear idea of what is going on, but it does somehting similar to what I had in mind. (not sure if that is a good sign though )
I have no clear explanation of what it is doing to be honest.
My idea, starting point, was that the resonnance would get folded, but then the high frequency part of this folded signal (in the VCF) would be removed/changed and the signal would be folded again, and so on.
Truth is, I will attempt to build this and it will sound like a big fart, but I guess that would nearly be a win.
This looks really really nice. Very creative, indeed!
When playing around with the simulation I get the impression that the frequency of the resonance can be a multiple of the saw tooth, which should sound harmonious, but also a completely different frequency. Furthermore the resonance will have quite a large amplitude. So I think that ‘tuning’ the resonance to the input signal’s frequency may be important to get a nice sound and that adding some amplitude limiting to the resonance would be usefull. When not tuned I wouldn’t be surprised if it would sound similarly raw like a ring modulator of sorts.
Yep, I really want to hear this !
Can falstad be used to generate an output file of the signals generated one could then convert to wav?
Thanks.
I thought about the wav idea but i dont think this is possible for various reason, first being that it would probably require a large computational power.
falstad does not seem to offer a way to export the scope signal, or any signal as far as I can tell when checking the menu system. The idea would be to create a short signal by starting a simulation and moving some of the controls, then freeze the output and dump that in a file (and then convert that to some audio format).
But there may be other simulation systems that do offer this. On the other hand, building it on a breadboard may be the easier way to get some sound.
It is pretty hard to listen to it but it gives a good idea of the sound it can make. The waveshape is really similar to one obtained in falstad.
I will try to add some CV to the breadboard to finish the tests.
Hi,
so I kept going on this as I was not really happy with the overall CV range of the diode filter.
I also had some click sound when opening and closing fast but that could well be due to the breadboard.
So I decided to move on the LM13700 (MS-20 style) filter. Also, as the resonnant filter idea is mostly only valid as a low pass filter I will use the Grrrr filter design for the main filter part which will give CV on resonnance and VCA as well.
I have come up with the following desgin on falstad.
As soon as the weather becomes more soldering friendly, I’ll give it a proper go ! https://tinyurl.com/2cdugmkd
Hey, it was actually happening with an enveloppe. I did use the latest schematic version of the filter (from the erica synth series, kindly provided) but to me, the range of main filter cut off was a bit too small… cutting and opening very quickly.
)
