Strangeness in NoiseMakers FilterTracking

[ENV1]

Updated to 4.22 today and played a bit with it so see if everything is OK.

While checking filter oscillation + keyboard tracking, i noticed something odd:

If the Cutoff freq is set to circa 34, everything is as expected. The lowest note (C-1) gives just about the lowest tone. (Inaudible but measurable.) Anything higher than ~34 is normal too. However, if the Cutoff freq is set lower than ~34 a strange thing starts to happen: Pitch now goes UP the lower a note you play, in other words there is a point where the keyboard tracking starts to invert. (The exact point (i.e. on what note) depends on where the Cutoff freq is between 0 and ~34. The 'range' of the inversion increases as the Cutoff freq is decreased below ~34.)


Example

Oscillators Off | LP24 / Cutoff Zero | Resonance Full | Keytrack Full | No Envelope

From C5 upward everything is normal: Higher note = higher pitch.

From C5 downwards everything is inverted: Now lower note = higher pitch.

(C5 itself is the 'inversion point'. Just produces a short pop, no measurable signal after that.)



Any idea what to make of this? Sure seems a bit unusual to me, (dont think ive ever seen anything like this before), but then again there might be an explanation i didnt think of, so im not sure if i should report this as a bug just yet.

[fluffy_little_something]

- Since you mention the update, is that behavior new? It is a rather old synth...
- Does it happen with all filters?
- And finally, does it even matter?

[Chris-S]

Hi,
I have an old version (4.1.0) installed and can confirm that filter keytrack is not working as expected.

Chris

[ENV1]

Since you mention the update, is that behavior new?

I had not noticed it before, but that doesnt mean it wasnt there before. (In fact Chris has already confirmed that it actually was.) I just happened to notice it today by chance. I didnt check the older version because i had already removed it and didnt feel like swapping DLLs around again.

Does it happen with all filters?

All filters except the one that has no resonance.

And finally, does it even matter?

If its a bug id say it does.

[Chris-S]

- And finally, does it even matter?

Using the self oscillating filter as a sound source is a common trick on subtractive synth's to produce nice flute tones or something.

[fluffy_little_something]

- And finally, does it even matter?

Using the self oscillating filter as a sound source is a common trick on subtractive synth's to produce nice flute tones or something.

Haven't used NoiseMaker for some time, doesn't it have sine and triangles waves?

[Chris-S]

You can use the filter as additional oscillator and also it sounds better than a "normal" sinus oscillator.

[Halonmusic]

Yeah filter tracking isnt working for me either.

[ENV1]

You can use the filter as additional oscillator and also it sounds better than a "normal" sinus oscillator.

Technically yes, thats how it can be very useful. But since NoiseMakers maximum keytrack amount is rather weak you cannot really use it as an additional/supporting oscillator in this case because an octave of pitch stretches across 3 and a half octaves on the keyboard, which means it is impossible to ever have it in tune with the oscillators.

(Actually its worse than that because the whole thing is 'variable' on top of it. With Cutoff freq set to 50 and full keyboard tracking, if you play a C3 then the next octave starts at G6, i.e. one octave of pitch spans the range from MIDI note 48-91. However, if you play a C2 instead then the next octave already starts at D5, (36-74), which is 3 semitones fewer than before. You get the picture.)


Not sure if this can be classified as a 'bug' but it sure is suboptimal behavior. Maybe we should submit a feature request for this one and ask nicely for a change, so that full keyboard tracking means that one octave of pitch corresponds to precisely one octave on the keyboard (and on all of them equally) so it works as it 'usually' does with 100% keyboard tracking.

[fluffy_little_something]

You can use the filter as additional oscillator and also it sounds better than a "normal" sinus oscillator.

Is the number of oscillators an issue with modern soft synths? Even ancient Sylenth1 has 4 oscillators with up to 8 waves each.

And how does a sine sound different from other sines? Unless it is not really a sine...

[Chris-S]

You can use the filter as additional oscillator and also it sounds better than a "normal" sinus oscillator.

Technically yes, thats how it can be very useful. But since NoiseMakers maximum keytrack amount is rather weak you cannot really use it as an additional/supporting oscillator in this case

Yes, my statement was not related to Noisemaker. Indeed this technique can hardly be applied to NM because of the bug (or design?).