I don't think it's aliasing but 1 has a TON of artifacts at max resonance and a fairly low cutoff compared to the others. I think that's what people have been calling aliasing. The difference in the amount of noise and behavior is obvious in moscom_electronic's post here: http://www.kvraudio.com/forum/viewtopic ... 0#p6431179Urs wrote:I would need an audio example to see what they mean. My guess is, due to the principle-induced difference in filter frequency, one filter method often has more "resonance locking" artifacts than another at a given oscillator frequency, or it pronounces some noise a bit more than another. That said, I don't think that any of the filters differ much in their aliasing behaviour, and that's also not the point of this.
In general, yes there is a tad of aliasing, there always is, "aliasing free" is a myth, but it doesn't make much of a difference for the result. The final version (which goes to 50+ kHz) can be tweaked for less aliasing, if need be.
I'm pretty sure that's why some people think 1 sounds terrible, while others kind of dig the instability of that filter.
