Change to the Vult Lateralus filter?


Does anyone know if Vult has updated their Lateralus filter recently? I used to run a patch with a couple of those as oscillators with the resonance cranked up and a couple of LFO’s controlling the resonance and cutoff CV. When you ran that through some heavy reverb the result came out as a beatiful and organic sound, almost like whales talking to eachother.

However I’ve been away from VCV for about 2 months and when I came back and updated my modules it would’nt work anymore. Actually I can’t get the filter so self oscillate at all anymore, even if I crank both drive and resonance to the max. I know for sure the filter worked as an oscillator early june as I had a presentation for my exam using it.

I tried (healf-heartedly :wink: ) to search for changelogs and here on the forums to see if I could find anything but I came up blank. Anyone tha thas some info on this?

All the love /Nils

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This thread explains the bug that was recently fixed.

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look towards bottom of thread:

Yeah, since the v1.18 “fix”, Lateralus needs a gentle push to get it to self oscillate.

It could be feedback from any of the outputs to the input, and then raise the cutoff to somewhere between 2 and 4 o’clock to initiate the self oscillation. Or feed any input, noise, a note, whatever, at any cutoff point for the briefest of time to kick off the self oscillation.

Once self oscillation begins you can remove the input (feedback or other), and the oscillation continues indefinitely as long as resonance remains high.

I suspect this behavior is an unintended side effect of the fix. I assume there is a sweet spot somewhere in the middle that preserves the self generated self oscillation, as well as eliminates the amplified “noise” at low input levels that I was seeing in the original.

As a side note, I have some patches with heavy delay/reverb that I hadn’t realized were taking advantage of the amplified noise. The fix significantly changed the sound of the patch. I was able to mostly resurrect the original sound by mixing in a minuscule amount of white noise.

many filters that self oscillate have a very small amount of white noise added just to give them this little “kick”.

Is this true in hardware or just VCV rack?

In Lateralus I had a detection of signal so, when the input level is zero, it would insert a bit of noise to make it self-oscillate. It seems like the noise I insert is not longer enough after the changes I made to the solver tolerance. I will improve this in the next release (soon).

@GrayCatMusic In analog filters, there’s already enough noise around that will make the filter self-oscillate. However in pure digital, because of the computer arithmetic, you can have zero noise, therefore it needs to be artificially inserted.


Cheers for the replies, mates. Still quite the beginner in the world of modular and didn’t know about there needing to be some slight noise for the filter to self-oscillate. When you think about it it sure is logical so should’ve been able to figure that one out :slight_smile:

I found an old backup on another computer where I had the 1.16 version so I’ll be using that one until I see a new update. Keep up the good work :slight_smile:

I did the same, even though I don’t really use the self oscillating that much I made some presets with tuned filter output and it’s nice when they work right out of the box, in stead of connecting extra cv/noise to them.

What @modlfo said about adding noise and analog is completely correct (of course).