any way to convert audio into FM suitable CV signal?

Tips and techniques for Minimoog Analog Synthesizers
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kcabdeef
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any way to convert audio into FM suitable CV signal?

Post by kcabdeef » Wed Jan 18, 2006 2:04 am

this probably makes no sense at all as I don't understanding anything of electronics, but is there a way to use external audio to FM the voyager's filter using it's CV input?

Same way for pedal inputs etc....

OysterRock
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Post by OysterRock » Wed Jan 18, 2006 3:02 am

I think I know what you mean. Yes, there is a way if you have an MF-101 or something else that generates an envelope.

Send the external audio to the MF-101, connect the ENV OUT of the 101 to an input of the Voyager (i.e. filter, pitch, volume, etc.). You can get some really cool sequencer type stuff if you run a drum loop through the 101 and control the pitch on the Voyager.

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MC
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Post by MC » Wed Jan 18, 2006 11:47 am

ENV OUT is not FM. Envelope followers generate a signal that "follows" the amplitude of an audio input. FM applies an unprocessed audio signal to the CV modulation input of a filter. The end result of both are very different.

If you want to use an audio signal to FM the filter, you may need a preamplifier with decent gain because the audio may be too weak to have any effect for FM. Pedal inputs are 0-5V, audio signals like guitars are a lot smaller than that. A moogerfooger FX box has a preamp that fits the bill, but the CP-251 does not have a preamp.

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Post by OysterRock » Wed Jan 18, 2006 11:59 am

Yes, you are correct, but I was thinking he just meant "modulate" and got the term wrong.

kcabdeef
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Post by kcabdeef » Wed Jan 18, 2006 1:33 pm

yes, I meant audio rate modulation. One of the immediate ideas would be to use the headphone output and feed it into the mod bus. You could FM the whole 3 oscillators with the whole sound output or you could use it to FM osc2 for example.

just to experiment in the most geeky way :)

So I researched a bit and line levels are about 1V right? You'd need to pull it up to 5V to get some decent signal. Isn't there specialized amps that have this exact amplification? some audio/CV converter?

Also, I've never thought much of the usefulness of the MF moogerfooger...but that envelope follower seems really cool :)

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