Keyboard with multiple zones?

[k brown]

A search didn't turn up anything definitively useful - did anyone come up with a way to do more than a simple keyboard split?

I'm working on something close to an approximation of the FM synth section of the Synclavier. I sneaked up to it with the additive oscillator version of First FM, but now I'm taking it closer to the full structure of the Synclavier's Additive/FM 'engine': four Mod/Additive Carrier pairs, each with their own vibrato and tremolo LFOS, portamento, tuning, panning and keytrack. Lotsa 'hats off' to Spogg for the 'Mystery' additive osc at the heart of this; it sounds terrific when phase modulated, and saved me a ton of work!

A function of the Synclavier I haven't figured out how to do is assign each Mod/Carr pair to it's own keyboard zone; so splitting the keyboard not in two, four sections.

FM-S copy.jpg (40.88 KiB) Viewed 10429 times

[Spogg]

My approach would be to use a DSP system for each mod/carrier pair. The raw pitch value coming out of the MIDI voices to poly prim is actually the key number, so a pitch of 60 is middle C (which I’m sure you know!).

There would be a DSP code box for each of the mod/carrier pairs, so in this case 4 of them. Each code box would have the pitch input, the lowest pitch value and the highest. If the pitch played is in this range, the value is output and can be used directly or converted to Freq 0-1 if needed. The advantage of this is that you could have overlapping keyboard zones, or dead areas, depending on what you want.

Now I may have overlooked something dreadful, but that would be my starting point at least. Plus, I’ve done stuff like this before. One thing to consider is that if a key is played outside a zone, the pitch output would be zero, which represents a frequency of 9.175799 Hz, so you would need an additional output from the DSP to enable audio or not for that zone. Or you could use the pitch output to block any audio below pitch 16 say, which would allow a minimum of 20.601723 Hz.

Yes, I do have a pitch chart!

[k brown]

Sounds like a reasonable approach - I'll see if I can puzzle my way through that.

Thanks - and again for your work on the 'Mystery' osc. Phase modulating that beastie really makes clear how the Synclavier could produce such complex sounds even though it's only four layered 2-op tone generators. I implemented the Synclavier's ability to shift the phase of each harmonic individually - fascinating to hear the subtle shifts in timbre from doing that.

[Spogg]

Thanks.

If you need any help… you know where to find me!