Formant filter request
Hello there,
it would be great if the shift knob on the formant filter would display the exact base frequency and be modulatable with a pitch CV signal.
the reason is that I am trying to make it work as a guitar effect, but I get unpredictable resonance spikes when a major overtone aligns with one of the vowel frequencies.
Also, it seems to me as if decreasing the bandwidth turns up the resonance at the same time. If that’s true, maybe an option to simply lower the rest of the signal would be enough to make it work.
any ideas are welcome :)
cheers
Comments
What you describe is the natural result of using a vowel formant filter with a chromatic instrument.
You can try to increase the bandwidth (BW) and shift the center frequency slightly until the resonances are reduced.
but the human voice is a chromatic instrument too, right?
shifting the center frequency works because it moves the vowel resonances out of the way of the overtones, but there is no precise way to control where the center frequency sits
i should add, I am using MIDI guitar 3 to determine the pitch of the guitar input.
a fixed offset from the note that’s playing would produce a more predictable behavior (I hope)
You can use another MIDI2CV module and use it to extract a pitch signal from MIDI Guitar, add a Scale & Offset module and use it to shift the Formant Filter frequency by a constant amount until it sounds right.
I ended up using midi guitar to control the pitch of a formant oscillator, which in turn acts as the modulator signal for a vocoder on the guitar input. The results are much better.
another little trick (which I made a video about a while ago) came in handy to extract more frequencies from the guitar: when you modulate the guitar amplitude with a sine wave an octave or a fifth below the playing pitch, you get a very smooth bass sound that you can send into an amp sim with interesting results. Requires MG3, but produces no additional latency. I’d encourage everyone to try this :)
Great!
I wonder how well Drambo's own pitch detector would work in comparison:
Of course, the pitch detector won't work well with chords but for single note melodies it could be worth a try.
Just did a quick test with a dry guitar recording, the results as as expected worse than MG3, but usable in my opinion. Especially for the format oscillator pitch, where the pitch alignment is not so crucial.
the AM pitch shift method might work better with a live guitar input where you feel your way into it.
however anybody who is interested in this stuff and wants to go beyond experimentation should consider grabbing a copy of MG, it’s a steal for what you get, especially on iOS :)