#188

Hi everybody, this is my first time posting here after quite a lot of reading, this looks like a really nice community and this thread in particular gave me a lot of ideas, inspiration, thanks !
I wanted to share with you an attempt at a FM synth I made in Reaktor, I haven’t uploaded it to the user library yet as I fear it is not ready / not that “good”. (it is my first time building in Reaktor…)
You can find it here : Dream Phase Machine 4OP V2.ens (8.9 MB)

My idea was to make a simple 4 OP “PM” synth, with a mod matrix, and envelopes for each mod index (feedback included that is 4 envelopes per OP, plus one for the OP’s DCA), so that you could program interesting evolving textures with only few OP. I also added a time modulated delay (by a simple LFO) in each OP, in the path of the “modulator out”, so you don’t hear it directly, only the effect it has on the carrier it modulates. It makes for all kind of comb filtering related crest and valleys in the modulation with short times and kind of almost reverb-ish space with some feedback, I find it interesting too.

Well if anyone has time and will to check it, and has feedback (ha!) I would be honored.

Have a good day !

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#189

Looking for tips on creating FM bell sounds (dx7-ish) in eurorack/vcv. I’ve been doing some reading up, and can’t quite produce anything I like. Examples greatly appreciated!!

#190

I have found this illustrated supplement to the rubicon pretty helpful in making bells and learning how to make FM in modular. It may or may not be helpful depending on how similar your set-up is/can be to Rubicon/Dixie combo. The basic Idea is to send the same pitch cv to both oscillators, pitch the modulator up an octave or two from the carrier (or experiment), then send a dynamically varying amount of the modulator to the fm input of the carrier (using a vca and env) and also send the output of the carrier to a dynamically varied vca/lpg/env. You can use the same envelope for both vcas or different shapes.

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#191

Thanks! That looks like an excellent resource. The patch you described is what I’m trying to build up in VCV rack, I feel like I’m getting closer. 1 Carrier osc, and two modulators mixed together, vcas + ega for each operator. Def bell-ish but still a bit off

Screen Shot 2021-02-09 at 4.20.33 PM
Screen Shot 2021-02-09 at 4.20.33 PM2198×1014 483 KB

#192

FWIW, I have found that the part that really helps the “bell” emerge with the rubicon is playing with the symmetry of the carrier. I’m not sure if there is a vco you have access to that would let you play with offseting the wave. it Doesn’t look like that VCO does.

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#193

Traditionally, the general recipe for FM bell spectrums is to choose C:M ratios that are highly irrational. This will produce an inharmonic spectrum that we associate with clangorous bells. A good starter C:M ratio is 1:phi, or ~1:1.61803. That’s a nice one because the numbers are close together, it’ll produce relatively close partials in the spectrum which will create a fuller sound. Big, beefy, bells. You’ll want to modulate decay of the bell with a exponential envelope and not a linear one, as that more accurately reflects the decay rate of a real bell.

From there, it’s a matter of tuning and adding variations (various FM configurations, C:M ratios, etc).

I quickly whipped up a basic starter FM bell using a classic FM pair and some exponential envelopes controlling modulation index and volume:

I’ll also attached the code I used to make this, which is read via my monolith system. Hopefully, this patch is readable enough to port to other systems. The modulation index ranges and frequency were found via trial and error.

patchwerk nodes

3 dmetro bhold 0 cabset # clock signal

150 # frequency (hz)

1 1.61803  # C:M ratio

0 cabget 1.5 3 0.1 expon # modulation index control

0 # feedback amount

8192 ftnew gen_sine fmpair -5 ampdb mul # fm oscillator

0 cabget 0.001 0.1 0.6 tenvx mul # amp envelope

0 cabget bunhold # free signal from cable

"bell.wav" wavout # write to wav

20 sr * _compute rep # compute 20 seconds of audio

Admittedly, it’s not the greatest bell, but hopefully that gets you in the right direction.

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