Kick synth changing the kick sound on new note

[tulamide]

@tulamide:
It doesn’t matter how many oscillators you have in a poly system, they will all start at the phase that is set for each of them. So if there is no phase input they will all start at phase 0 (or their “native” phase). However, when you have a note sounding and you play another additional one, a new channel is opened and those “new” oscillators will commence at their given phase and this will almost certainly not align with the existing ones currently sounding.

So, there is no way to somehow keep track of the current phase and start the new note at the phase, the previous note is at? I may be confusing things here, so bear with me, but I see a lot of LFOs that can be switched to either re-start with the new notes, or keep their phase for the new notes as well. How is that done then?

[nix]

It's done with 'poly 2 mono' & 'mono to poly' (ie. in blue) afaik
Any other way would be very clever

[Spogg]

So, there is no way to somehow keep track of the current phase and start the new note at the phase, the previous note is at? I may be confusing things here, so bear with me, but I see a lot of LFOs that can be switched to either re-start with the new notes, or keep their phase for the new notes as well. How is that done then?

Tricky one!

For a polysynth's audio you would need to define a “master” from the channels sounding, and broadcast its phase. The master’s phase would then need to be sampled at the point of channel creation for new notes. However the master’s channel would of course have to be open all the time, or would have to be determined dynamically as notes come and go. Another thing to consider is that new notes would normally be at a different frequency from the master so there would, arguably, be no benefit to dynamically determining the initial phase for new notes. This is because only the very first instant of an oscillator’s run would be in phase with the master.

LFOs are a different case. They can be polyphonic or mono, depending on requirements. A poly LFO will be created for each new note and would normally start at their set phase. This means if you’re using a poly LFO for vibrato every note will likely have a different phase of LFO and this can sound more “phat” or rich (and use more CPU!). However, you may want to have all the notes modulating in sync, irrespective of the number of notes and when they were pressed. This would be like putting your polysynth’s output through a mono pedal effect or Leslie speaker, so all the music then has the same modulation.

In the latter case you would have a mono LFO and, as Nix says, convert its output to poly to feed the poly section of the schematic. In this case, when a new note is requested the channel will open and the current LFO state will be read by the new note and will be in step with any other notes sounding.

Now here you could arrange a system whereby the mono LFO is reset every time a new note is pressed. I’ve not seen that done in practice but, doing a thought experiment, it might sound quite odd. This is because currently sounding notes would experience a jump and maybe a click every time a new additional note is pressed, due to the LFO being reset from an unpredictable level.

Cheers

Spogg

[nix]

Nice one Spogg-
I can see the way to make the polyphonic free running LFO now.
We can read phase(having manual phase implemented),
a sample before new note, and adjust the phase of new note's LFO accordingly-- I think

[djbrynte]

Spogg made this working ty pal. ur so fuck... pro man!

[Spogg]

There were a few issues with the schematic but there was one that I didn’t think of here:
If you have a kick drum sound (or any decaying percussion) you may want the envelope to last for say half a second. This means that if you have a tempo greater than 120BPM the sound will re-trigger before the envelope has completed. If you have 1 voice set on the MIDI module, the note has to instantly be stolen and this can be problematic (random clicks etc.) if you want every sound to be the same.

The solution is simply to set more voices, a minimum of 2, to allow faster tempos. This led me to check my old Quilcom Beater, and I must have seen this before because I had that set internally to 4 voices. Being so ancient I’d forgotten about this issue.

Cheers

Spogg

[djbrynte]

Exelent spogg it actually seem to be working.