Moog Music Forum

hey guys

I read about new moogerfoogers all around this forum the last weeks and I mentioned that nobody thought of a real moogerfooger pitch-shifter. Like POG (ehx) for example or the WHAMMY(ies)... huh? what do you think? imagine an analog pitch-shifter where you would be able via the cv inputs to control higher octaves, fifths e.t.c. with an exp. pedal. An analog moogerfooger whammy...

Mike get to work!!!

regards

I'm not entirely sure but I think analog pitchshifting is impossible.

Yup - pitch shifting is one of those things that digital is good at. Can't pitch shift in analog.

what about the pitch shifting with the 104 when you switch delay times? when i first got mine i thought wow what a great pitch shifting sound, they should make an octave or harmony pedal type thing.

That's a well known effect, it's been tried and nobody's been able to get a consistent pitch shift effect using analog BBDs.

The first pitch shifters were the Eventide Harmonizer and the MXR Pitch Transposer, both in the late 70s. Both were digital machines in the prime time of analog.

You can get lower pitches easily enough with a frequency divider, it's higher pitches that are tricky. It only works with a monophonic signal, too. It's kind of possible with a ring modulator, but far from the results you'd get with a digital device.

The ideal situaion would be a digital device with CV inputs for control.

Maybe we can't have a pitch shifter...but a Bode frequency shifter would make one sweet looking moogerfooger

aren't the pog and the zvex johnny octave analog? those are pitch shifty

An analog octave pedal is easy to do because you are just multiplying the signal by itself. Similar to ring modulation only instead of multiplying the input signal by a carrier signal, you simply multiply it by itself. This results in two frequencies: one at twice the frequency of the input (doubling frequency means it sounds an octave higher) and one at 0 Hz (which is inaudible). You can do it with the Moogerfooger Ring Mod by using a Y-cable to insert your audio input into the carrier in. This is not the same as what a pitch shifter can do.

I was way ahead of you on the pitch shift trick with the ring mod - and it doesn't work very well. It only works for waveforms with few harmonics and you only get octave pitch shift, no semitone or micropitch shift.

I asked Moog Music about the ring mod trick and they said it is a limitation of the multiplier IC used in the ring mod. That makes sense if you do the math with higher harmonics - the modulated harmonics increase in frequency EXPONENTIALLY and they exceed the bandwidth of the IC in a hurry.

You're right, it doesn't work very well on the MF Ring Mod, but isn't multiplication how an octave pedal works? How else is it done? I am genuinely interested in learning.

An octave pedal is a divider, not a multiplier. It generates a pitch that is an octave lower than the original. Divider circuits are much simpler than multipliers. The simplest divider can be built from a TTL J-K flip-flop IC.

That's how they make suboscillators for VCOs - it's an octave divider circuit.

The only con with dividers is that the output waveform is a square wave. You can filter it but in most cases it won't resemble the harmonic structure of the original waveform.

hey... how come electroharmonix is doing it??? ( www.ehx.com ..POG pedal..) If electroharmonix is doing it then moog will definetely do it better. right?

yeah, i mentioned this already, plus the zvex johnny octave which sounds really great too btw. but i just read a description of the johnny octave and he says it's controlled by a ring mod which is how he gets the pitch shift. still wondering about the ehx. maybe it's digital?

Where does it say that the POG is analog? You think that would be a selling point if it was, but they don't mention it anywhere. It must be digital.