Seeking Understanding: Artifact Analysis in Multiband Distortion

[Mighty23]

@DanH Thank you very much for your response. I'd like to ask if you've used a samplerate different from 48000 and a buffer size of 480.

[Dan Korneff]

Sub frequency artifacts (most likely "pre-ringing") can be a result of linear phase filtering.

[Mighty23]

@Dan-Korneff What should I try to prevent or correct this?

[Lindon]

@Mighty23 said in Seeking Understanding: Artifact Analysis in Multiband Distortion:

@Dan-Korneff What should I try to prevent or correct this?

use a high pass filter set at 20Hz

[clevername27]

@Dan-Korneff Isn't pre-ringing a result of audio playing backwards?

[clevername27]

@Lindon Do you mean a low pass filter, as in preventing aliasing?

[Dan Korneff]

@clevername27 Not that I know of. Playing the audio backwards is actually a possible solution to the issue.
In general, all EQ creates ringing. It usually occurs AFTER the signal, so it's masked most of the time. Linear phase filters create a ripple in the audio at the crossover points (aka: ringing) Due to the latency caused by linear phase filters, some of this ringing occurs before the transient and is now audible.

[Lindon]

@clevername27 said in Seeking Understanding: Artifact Analysis in Multiband Distortion:

@Lindon Do you mean a low pass filter, as in preventing aliasing?

no - several types of distortion approaches produce harmonics - in fact in a lot of cases this is what you want - but these can appear above your source freq. and below it, looking at the op's image there seems to be a low freq harmonic being added at around 20Hz, its a pretty simple High-pass filter to remove this.

[Mighty23]

@Lindon said in Seeking Understanding: Artifact Analysis in Multiband Distortion:

ooking at the op's image there seems to be a low freq harmonic being added at around 20Hz

Does this undesirable occurrence associated with distortion have a specific term?

[Lindon]

@Mighty23
https://en.wikipedia.org/wiki/Intermodulation