Foogers and Audio

[Lux_Seeker]

I have not tried it but I have always wondered about non conventional ways to use foogers. One of the things I realized about CV control is that as long as the CV can be kept within the acceptable voltage range, there are many ways to produce voltages that while may not be common, may be musically interesting.

One application I thought about is this. What if an audio signal was used to create a CV? I know that audio signals are of low voltage compared to CVs but what if say the CP-251 attenuator was used or even the lag processor. The attenuator might get the voltage up to usable levels and the lag processor might create an interesting effect.

Has anyone done this with audio. Just curious.

[Just Me]

That is called frequency modulation. Try it with your Ring Mod.

[Lux_Seeker]

Not true, if you use it to modulate pitch its FM or amplitude (minus the carrier) then ring mod. That's in the box thinking. But what if you modulate way the waveform CV input on the Frequbox or the cutoff frequency on the filter? Now we are out of the box. Ideas?

[Klopfgeist]

I haven't tried this yet, but I wonder how well it would work if you draw your own waveform in a daw/audio editor, and then send it out to modulate something. Or take a short snippet of audio and pitch it really far down (un-audible ranges) and loop it to modulate something.

[moremagic]

That's in the box thinking. But what if you modulate way the waveform CV input on the Frequbox or the cutoff frequency on the filter? Now we are out of the box.

Not really, one of the reasons modular synthesizers are so popular with some people is because you can plug audio signals into cv ins and control signals into audio ins

[EricK]

Am I right to say that this is what a lot of the EURORACK companies are doing?

Like those synths that don't use oscs and filters but create sounds wit alternate methods?

Eric

[Lux_Seeker]

I know modulars can do this and people keep trying to point me in the direction of a modular. The truth is that I am always looking to crreate a hybrid, somthing that allows digital control but still provides at least some of the flexiblity of a modular.

I am not asking if modulars can do this or if there is something that can do this. I know that modulars can do this but what I want to know if anyone has done with with foogers. I am not in my studio now and don't have foogers here but Monday and Tuesday I will try this. I will let you know how things work out.

[Just Me]

Actually, your Foogers are modules from a modular. The CP-251 is 8 modules in one footprint. The RM is 2 modules, etc.

[Lux_Seeker]

Actually, your Foogers are modules from a modular. The CP-251 is 8 modules in one footprint. The RM is 2 modules, etc.

I appreciate all the comments here but I think things are getting away from my orginal post. I understand that modular synthesizers can use audio for a CV and I understand that foogers are like modules.

That being said, I am simply asking if anyone has used audio as a CV and if so how. There are many ways to do this but from what I have seen, no one has tried. I will see what I can find out by simply doing it. Unless voltages get over 5 v I don't think I can damage anything and I am not using the CV as audio which could cause problems with other equipment.

[latigid on]

I have not tried it but I have always wondered about non conventional ways to use foogers. One of the things I realized about CV control is that as long as the CV can be kept within the acceptable voltage range, there are many ways to produce voltages that while may not be common, may be musically interesting.

One application I thought about is this. What if an audio signal was used to create a CV? I know that audio signals are of low voltage compared to CVs but what if say the CP-251 attenuator was used or even the lag processor. The attenuator might get the voltage up to usable levels and the lag processor might create an interesting effect.

Has anyone done this with audio. Just curious.

You would need some kind of amplifier (not attenuator) to boost the audio signal to line level or even higher) Peak-to-peak voltages are on the order of millivolts for audio and volts for CV.

An obvious example of this is vocoding. The audio input, be it voice, drums etc. is filtered into bands and the envelope pattern is overlayed onto a filtered carrier signal.

With other CV destinations, audio would just be acting as a complex waveform. Like "Just Me" said, the result would be frequency modulation of the CV, but in a complex way.

The thing about CV, like LFOs and envelopes, is that they're very consistent. Using audio would not be as predictable, maybe that's what you want.

[Lux_Seeker]

A few comments here.

In the vocoding example, you are talking about using a side chain basically so the audio signal in not really mixed with the CVs. The CVs are used to set filtter level but the carrier can be at audio levels.

My mistake on the attenuator since these only reduce voltage levels.

Another option is to use the output that would normally go to speakers from a power amp. I have a small amp head I already use for experimental purposes which might work but I am a bit concerned with the voltage levels. Foogers are to expensive to blow them out with high voltage levels.

I don't agree that what I am talking about is FM. FM has a very specific meaning, its the modulation of frequency. Let's say you plug an audio signal (at sufficient CV voltage level) into the waveform CV in. That is not FM. No doubt it will create a complex signal and yes, that is exactly what I am trying to get at.

The benefit of FM was that it created several sidebands (compared to FM) which respond dynamically to signal level and therefore, can mimic the characteristics of a natural instrument.

In many ways, I look for similar ways to create complex waveforms. Using audio to control CVs seems like a good way to do this.

[EricK]

Isn't Wendy Carlos's vocoder actually 10 envelope followers and 10 VCA's for 10 channels of vocoding?

Did they ever sing through that one? If they did they they actually were using the audio to create voltages.

[Lux_Seeker]

It may sound like a technically but a vocoder uses envelope followers to create a CV which controls a filter. So the CV is not direct audio. If I am wrong I stand corrected but this is my understanding of how a vocoder works.

[latigid on]

In my book, modulating any parameter with an audio frequency signal is FM. Technically, modulating with a low frequency signal is FM too, but we don't call it that, as it only "sounds like FM" once the rate of modulation approaches audio frequencies.

If you want to hear the result of audio modulating a filter, check out the Sherman Filterbank.

The "FM" knob increases the amount of modulation going to the cutoff frequency. With no input in the rear socket, the source is the incoming audio signal itself. I can only describe the result as "FM-ish"; i.e. bite-y, clangorous sounds which intensify with mod. amount.

The sound is similar when the LFO is set to a reasonable depth and is turned to high frequencies (above halfway). Here, the sound, also FM-ish, is much less dependent on the audio signal present and affected more by the rate and depth controls of the LFO.

[Lux_Seeker]

I guess its a matter of semantics what you call FM. I don't know what you call it in you book but FM synthesis has a specific meaning in regard to modulating frequency, thus the term FM.

I would also agree that many "gritty" sounds are associated with FM but one of the reasons that the Yamaha DX7 and other FM synths used sin waves or waveforms with only a few partials is that the sideband stucture was less complex and more musical or less "gritty".

As the amplitude of the modulating signal increased, so did did banks and grit. This mimics the initial attack phase of many instruments.

I have also heard and listened to samples of the Sherman Filter Bank. Frankly, never a fan. I tend to favor less harsh sounds. FM itself can be tamed its just a matter of using carriers with only a few partials. As the partials and dynamic nature of those partials increase, the ear is going to hear what you call "grit" which is really just a complex harmonic waveform that brain can't easily identify and hears as grit.

Using sin wave or low partial carriers results in more pleasent bell like sound that FM synthesizers like the DX7 are so famous for.