Ring Modulator Theory

[zachary vex]

if you decrease  the "depth of modulation" on a ring modulator by reducing the carrier amplitude to zero, the ring modulator goes silent.

[spectraljulian]

for video demonstrations of the newest Z.Vex Effects sequenced ring modulator, the RingTone, visit this page:

http://www.zvex.com/ringtonevids.html

they are large (24M each) and they require full download before play (right-click and download or, on mac, control-click and select download.)

Do the pots work like they do on the seek trem where turning them all the way down makes them get skipped?  Using a ringmod for harmonics with chords is nice, but I wouldn't always want to have 8 chord sequences.  Also, I change the blend on my EHX frequency analyzer pretty frequently (the knobs are big enough that I usually just nudge it with my foot)  I think having it inside as a trimpot is sort of a drawback.  If you had the blend as a 10th pot on top, I think it would make the ringtone blow the EHX Frequency Analyzer out of the water. 

I'd say the moogerfooger ring mod is still the king of ring mods, but for a ringmod that outdoes the Frequency Analyzer and is easy to use, I think the ringtone would be a winner. 

[DiyFreaque]

if you decrease  the "depth of modulation" on a ring modulator by reducing the carrier amplitude to zero, the ring modulator goes silent.

Exactamundo, which is why 'percent of modulation' means very little here on a dynamic basis other than the actual volume of the signal out.  With AM (in the audio domain, such as modulating a VCA) the timbre of the signal will vary dynamically with differing levels of applied modulation, due to changes in ratio of sideband to carrier.  The timbre of a ring modulator will remained essentially unchanged, but the amplitude will change.

Obviously, in the RF domain, a demodulated AM signal will drop in volume with lower depth of modulation, until only the carrier is left to quiet the receiver.  That has little to do with stompboxes, however.

In the sub-audible domain, a DC coupled RM presents an interesting new twist to LFO's if one looks at it in terms of one signal's amplitude multiplied by another signal's amplitude.  I built a four quandrant mutliplier into my synth mixer module to handle both sub-audible and audible signals.  For subaudible, a ring modulator can work as a sort of voltage controlled inverting/noninverting attenuator.  For example, with a  sawtooth LFO wave into the carrier and  a slower sine wave LFO into the modulator,  the amplitude of the sawtooth will increase, fade, increase again 180 degrees out of phase, fade, and so on and so forth, at the rate of the sine wave.  Makes for groovy VCO/filter modulation.  This is also handy for modulating envelopes. A RM can also be used for waveshaping in VCO's, etc.

Cheerio,
Scott

[SeanCostello]

Does a Flanger or chorus have carrier frequencys? what is the carrier frequency in a flanger or chorus?

In a flanger or chorus, the delayed input signal is the carrier signal, and the modulating signal is the LFO. It is FM. Increase the depth and frequency of the LFO, and you will get sidebands that display the characteristic Bessel functions for amplitude. I'm not going to explain Bessel functions - use Google to give a better answer than I would.

What different ways is there to do modulation? with a modulator? what other ways?

Frequency modulation, where the input signal is the modulator, and the carrier is a sine oscillator
Frequency modulation, where the input signal is the carrier (through a modulatable delay line), and an oscillator is the modulator
Single-sideband amplitude modulation
Single-sideband frequency modulation
Phase modulation (modulating the phase of the input signal - usually done with single-sideband techniques)
Waveshaping, where the input signal phase modulates a table
Phase quadrature waveshaping
Filter cutoff modulation
Filter resonance modulation
Allpass filter phase modulation (nonlinear phase relationship)
Pulse width modulation
DC Bias modulation through nonlinearity

There's more. Lots more.

Sean Costello

[markphaser]

Sean Costello

Can u list more please about modulation

[theundeadelvis]

I have a moogerfooger ring modulator and I think I need to study everything in this thread just to understand how to use it (I do love it though). I watched the ring tone demo and Zachary Vex is my new idol. Not only is he an electronics genius he is an artist of every sense of the word. Z.Vex if you ever are seeking an apprentice (we could even do a reality show haha) I would sell my soul for the opportunity! 

[zachary vex]

thanks.  i'm truly surprised nobody ever offered an analog sequenced ring modulator before... it's a pretty simple idea, really, and it's the only thing that makes a ring mod useful.