Module to convert saw to sine?

Does one exist? I thought I might try recreating Yamaha’s formant synthesis in Rack. I know a saw to sine converter exists in Serge’s Triple Wave Shapers and other hardware, but haven’t found a software equivalent. Thanks!

Why not just use a sine?

In any case, most waveshapers will convert a tri to something sine like

Formant synthesis is achieved with filtering, from what i’ve heard and tried, the base waveform makes little difference

Here you go. The reason is a saw core derived sine wave is not as clean and pure as a triangle core derived sine wave. There are waveshaping glitches. You can cheat in digital, of course.

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Ok, but pretty subtle.

I’m sure there are various ways, but, yeah, that is a pretty direct way. But the waveform does matter a ton. It needs to have lots of harmonics. Narrow pulse is like human vocal chords, but you are right anything with lots of harmonies will work.

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I don’t have a particular module in mind, but if there is a “scannable” oscillator or LFO that produces a sine wave, that would do the trick. Scale the incoming saw wave so that its highest and lowest values represent the same phase, then send it into the oscillator’s phase input.

I think the most common method uses diodes as rectifier to get triangle and then filtered to sine like what I shown. I am more of a DIY-er than an analog circuit expert though …

Yeah, if it is an analog circuit, the waveshaping glitches in triangle and sine will be more apparent e.g. Moog transistor sawtooth VCO etc. Analog saw core’s triangle will be glitchy and triangle core’s saw will be glitchy anyways. You can’t get best of both worlds unless you use a digital oscillator.

Anyways, sine with some harmonics is sometimes preferred by some.

Another option that I think of lol

Not sure we need new modules for that if everyone learn a little bit more about waveshaping.

I think my little shaper will do all these things. With selectable oversampling. And dc removal.

I had totally forgotten that in the 70’s most vcos generated saws, which were then converted to tri as you describe. The Curtis chips were the parts common analog VCO that generated triangles directly.

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