Filter Harshness

I’ve been comparing different filters and when you push the resonance to the point that things sound harsh, is that a sign of aliasing? The new Oxidlab filters flat out admit some aliasing and even provide an indicator light to let you know (if your ears aren’t already bleeding) that you’re getting some aliasing. Can it be assumed that similar harshness in other filters is also a sign of aliasing?

Not that it is a bad thing in all cases. Certainly not in my deranged “tunes.”

I’m by no means a dsp guru but perceived harshness in a filter can be just the distortion from the amplification or self-oscillation for example. Those (or the wave you fed in :P) can result in aliasing but it’s not the same thing, you can still feel the filter is being harsh without actual aliasing. I’m guessing the filter you mention shows the amount of clipping distortion? It does relate to the amount of aliasing present since clipping can introduce aliasing artifacts but afaik to measure aliasing in itself is only straight-forward if you know exactly what kind of wave you are trying to generate. But I’d like to see a general purpose alias meter module haha.

If you have a bit of time check out the first few pages or more in Circles Sines Signals. It explains very clearly what aliasing means through nice graphics.

One thing I know for sure is that I’ll turn off antialiasing in any videogame I can :wink:

It’s a good question. I certainly looked at the aliasing on those filters and it wasn’t as bad as some but it was there? I don’t know if you can have a “harsh” filter without aliasing. The Vult filters have tons of (good) distortion, but not much aliasing. People don’t thing they sound harsh.

If you are interested examining plugins for aliasing, we have a whole repo devoted to that. It’s a little VCO-centric, but you can adapt the techniques to filters.

Sorry, english isn’t my first language, I’d use “harsh” for a screaming self-oscillation from some Vult filters. Not saying it as a bad thing though.

Fair enough!