Unmirrored waveform oscillator

Steffenvy

I think it would be nice if the oscillator node had the option to give a custom wave curve, like this:

Setting the oscillator to sawtooth, multiplying by 1.5, and then using a waveshaper node almost works, but the result has random noise.

j_w

Steffenvy the result has random noise

To reflect specifically on this...

This is caused by the fact that the oscillator node's output is band-limited (or anti-aliased) for the sawtooth wave (and triangle and square), which causes the signal to swipe through the shaping curve not in a perfect linear fashion, but with some "shaking" going on near the edges -- if that makes sense the way I'm describing it.

A quick and easy fix is using one or more lowpass filter nodes to try to attenuate the noise in the higher frequencies, like this:

Note that I'm also using a highpass filter here to remove the DC offset.

Another, slightly more complex alternative is using the Timer Node to construct a mathematically accurate sawtooth-like wave.

j_w

Steffenvy I think it would be nice if the oscillator node had the option to give a custom wave curve

This sounds like a great idea (pun intended), how do you suggest this would work? Something like just simply drawing the audio signal on a canvas, or something more advanced, like drawing the spectrum of the signal? The latter is something that's in the works, but is kinda far from release.

Steffenvy

Drawing the audio signal would be nice, just like using the waveshaper node, except with the end points defaulting to a value of 0, and an option to mirror it or not. It could also be done in a way that the deprecated horn and organ are presets of this curve (even sine (approximation), sawtooth, square, and triangle could be presets), and it would be useful and informative to be able to modify these default curves and see directly how modification (asymmetric or not) of the waveform affects the sound. Especially because multiplying by the square root of 2 wouldn't be necessary:

j_w

Steffenvy

If it helps, the 0.5.7 update added the Fractional Node, which you can use to create a perfect sawtooth wave without band-limiting, and then feed that into the waveshaper to avoid aliasing around the edges.

Here's an example: https://www.audionodes.com/s/yQvZ5hHsQS/

Steffenvy

j_w Shouldn't there be a constant range transform from 0,1 to -1,1 before the waveshaper? Even so, it doesn't work on my end:

It seems waveshaper is just all around broken:

j_w

Steffenvy

Shouldn't there be a constant range transform from 0,1 to -1,1 before the waveshaper?

As a matter of fact, yes, there should be (I'm wondering if I shared the wrong snippet), exactly like you configured

It seems waveshaper is just all around broken

I've checked it out and it sounds like you are right, the Node fails to correctly restore itself (e.g. when you restart the app): it gets stuck too early on something that's supposed to smooth transitions between 2 changes, to avoid clicking while editing

(unfortunately, this is some pretty old logic that was left unattended)

The fix for this will be in the next update (probably next week, brought earlier to get this issue, and another bugfix out)

Thanks for the heads up on this one, and sry about the confusion

j_w

Steffenvy

BTW, if you grab one of the control points and keep making small moves with it for about a second or two, you'll hear the issue patch itself up, although that'll only "fix" it until the next restart (or until the Node is duplicated, etc.)

j_w

@Steffenvy the update is going out right as I'm writing this, the Waveshaper Node should be all good now

It may take a short while until it becomes available everywhere (both the web app and the downloads go through a CDN), but it's on its way

I'll pop the release notes shortly after we tested everything else on live as well

Thanks for hanging in there, hit me up if you find something else is wrong

j_w

https://www.audionodes.com/s/TvKeDr7Dkr/

waveshaper

Close enough I'd say

Note that implementing custom drawn waveforms is still planned down the road, but unsure when

The closest thing being worked on RN is the Pad Synth Node, where you draw the spectrum of the waveform (instead of the waveform itself), but it's still experimental