The Rhodes Chroma was a very interesting instrument that hid it's uniqueness and complexity beneath a UI that was sadly common (for understandable reasons) in those heady last days of the first wave of analog synths and the emergence of digital - a panel full of buttons and a slider (or two, maybe three) to enter data. Especially galling in the case of the Chroma because it's audio signal path was not fixed, but had 16 different configurations; one had to memorize them all or keep a chart always handy! There were a few hardware knob-per-function 'breakout boxes'; one is still being made, I believe.
One could think of the Chroma as a Yamaha CS80-like instrument, but with re-configurable signal paths - two identical synth lines of VCO / VCF/ VCA + two envelopes, in the Chroma's case each line has a dedicated LFO, rather sharing a single one like the CS80. Both instruments had velocity and poly aftertouch. Both had VCOs that produced only Saw and Pulse waves, but in the case of the Chroma, the Saw also responded to PWM (they called it 'Saws').
For my plugin I 'luxed the oscillators so that Saw can crossfade to Peak (actually, 'Peaks', as it too responds to PWM), and Pulse crossfades to Tri. Also, rather than the oscs switching Saw, Pulse, White Noise or Pink Noise, I have a bipolar crossfader for Osc > White Noise or Osc > Pink Noise. Similarly for the Ring Mod, rather than being patched in or not, the oscs crossfade to the Ring Mod.
The Chroma's filters were switchable 2-pole LP or 2-pole HP, here I've done the filters like CS80 - both are HP in series with LP, and LP can toggle to 4-pole. Filter keytrack is given it's own slider, rather than taking up a mod input.
The VCAs have, again like CS80, Sine mixers added; here they can be at-pitch or down one octave.
- CROMA flexPatch copy.jpg (185.79 KiB) Viewed 17644 times
As far as the audio path reconfigurations, the Chroma's ads liked to boast that there were 16, but that was a bit of a cheat because one of them was just a single one-osc synthline with double the polyphony; probably not used often and irrelevant for a vst. There were actually only four 'Patches'; all the others were these same four with addition of Sync, Ring Mod or Filter FM. By doing this with patch cables, not only can you
see your patch, but one can patch any way one pleases.
Rather than PB and Mod wheels, the Chroma had two bipolar levers that were freely assignable. So here, both PB and Mod wheels are available in the mod drop-downs, and there's a button to convert the Mod Wheel to bipolar.
NOTE: 8/2/20 - Bummer! Couldn't export this to 64-bit because the patch cord system (from SM days) won't work within FS4. So this will need to remain 32-bit until a patch cord module that's FS4 compatible becomes available.
I
have done a 64-bit version with drop-downs replacing the cables:
https://ln.sync.com/dl/62c9b9f70/bbjdaw ... 9008960004