Frequency pedal

[bigmufffuzzwizz]

I saw this band recently(2 piece bass and drums) and they had such a wild sound! At the end i lurked up to the front and noticed the guy had a moog freqbox pedal. It was making his bass sound absurdly large and heavy! I was wondering if this would be a possible suggestion for a new project as those pedals are $300+.
Can anyone give me an explanation of what that freqbox pedal is doing. 
Maybe there's a DIY layout alreadly?

[k.rock!]

I agree with this one!

Don't mean to hijack your post here, but I think any Moogerfooger pedal project would be awesome! I know they may be pretty complicated but heck, I'm sure everyone here is up for a good challenge 

[JakeFuzz]

I was checking this out the other day as well and though it was really interesting. My guess is that it is using an envelope follower to control the gain of a VCO, the right half of the pedal uses the same envelope follower except now it also controls the frequency of the VCO, the sync tracks the frequency of your guitars input signal and sets the frequency of the VCO to match. I am really not sure what the FM amount is doing. The mix just mixes the clean and wet signals together. I think the most interesting thing about this one is how you can blend between waveforms, I would love to see how they did that, my guess is digitally.

I would say in a basic functional form this would be reproducible. Would take quite a bit of work to get a nice DIY ready layout though.

[jkokura]

Jake, I think you need to participate more around here. I think your insight on this one and in other places is awesome! I'm good at putting pedals together and getting them working if they aren't and I'm starting to get much better at understanding how they work, but boy I like it when people like you chime in.

To the OP, have you looked elsewhere to see where else we might find some more info? Where have you looked/not looked and what have you found?

Jacob

[JakeFuzz]

Jake, I think you need to participate more around here. I think your insight on this one and in other places is awesome! I'm good at putting pedals together and getting them working if they aren't and I'm starting to get much better at understanding how they work, but boy I like it when people like you chime in.

To the OP, have you looked elsewhere to see where else we might find some more info? Where have you looked/not looked and what have you found?

Jacob

Thanks Jacob. I will try to participate a little more  . I am actually designing a pedal with envelope control (I lifted my follower out of the meatball) and this pedal came up as a part of my research. I really enjoy original/unique pedals like this and seeing how they've combined different analog devices to make something really wild sounding. 

[bigmufffuzzwizz]

I was checking this out the other day as well and though it was really interesting. My guess is that it is using an envelope follower to control the gain of a VCO, the right half of the pedal uses the same envelope follower except now it also controls the frequency of the VCO, the sync tracks the frequency of your guitars input signal and sets the frequency of the VCO to match. I am really not sure what the FM amount is doing. The mix just mixes the clean and wet signals together. I think the most interesting thing about this one is how you can blend between waveforms, I would love to see how they did that, my guess is digitally.

I would say in a basic functional form this would be reproducible. Would take quite a bit of work to get a nice DIY ready layout though.

I partially understood that. haha I will have to do more research on this topic to better my understanding.

To the OP, have you looked elsewhere to see where else we might find some more info? Where have you looked/not looked and what have you found?

I haven't done any research on it yet but i will look around and see what i can find. I'm thinking if we can come up with enough information bean might consider it 

[bigmufffuzzwizz]

Another thing i noticed about the moog pedal was when the dude would hold a note out sustained, it would begin to decay. when this happened the led would change color and flash corresponding to how the decay was happening. or something like that. Really interesting!!! too bad most of the demos i found on youtube were people using it with techno examples. just doesn't do it justice for me.

[bigmufffuzzwizz]

Here's the "official" description.

The MF-107 FreqBox(tm) is different from other effects – the effected sound is not a processed version of your input signal, but the sound of the input signal modulating an internal oscillator. It contains a VCO with continuously variable waveshape, and the capacity to modulate that Oscillator in the following ways:

- the VCO can be hard synced by the input signal
- The VCO can be frequency modulated (FM) by the input signal
- The VCO frequency can be modulated by an envelope follower which tracks the dynamics of the input signal
- The Amplitude of the VCO also tracks the dynamics of the input signal

Hard sync is a classic analog synthesis technique where the start of an oscillator's cycle can be reset by another. The oscillator being synced takes on the frequency characteristics of the other oscillator, and when its frequency is swept, it reinforces the harmonics of the fundamental frequency. In the case of the FreqBox, the input signal is used to reset the FreqBox's VCO.

FM is a technique used to get really rich sounds from simple waveforms. The type of FM used in the FreqBox is linear FM. Sounds range from gong or bell-like tones to sizzly sweeps.

The FreqBox, like all moogerfoogers, works with any instrument to line-level input. In addition to the panel controls there are control inputs for use with expression pedals or control voltages and control outputs for interconnecting moogerfoogers like you would a modular synth.

But now beginning to understand what this means! Think i'll need to start with VCO and oscillators.

[JakeFuzz]

VCO is a voltage controlled oscillator. Think of it as something that puts out a single frequency waveform (think the sine wave "A" note that comes out of your guitar tuner) but now you can control that frequency with say a potentiometer or the envelope of your guitar signal (any voltage source that can be predictably varied).

Almost all of the craziness of the Moog is in how the VCO frequency is controlled. I am starting to think FM modulation is just an amplitude controllable LFO (low frequency oscillator) which oscillates the VCO frequency about it's selected point, which would account for the introduction of sideband frequencies. The most difficult part is how you will mux the final three control voltages together. 

[JakeFuzz]

A block diagram of whats going on inside. You can see having a good, versatile VCO is key in this design.  

[JakeFuzz]

- The VCO can be frequency modulated (FM) by the input signal

Hmm, so no LFO, then the modulation frequency is the same as the input frequency? So the guitar signal would be turned into a control voltage (or maybe you could just use it as is) and set to control the modulation of the VCO's frequency. Sorry for thinking out loud, this is very interesting.