ARP 2600 - Ring Modulator

The basic principle of ring modulation involves taking two input signals and multiplying them together. The resulting output signal contains a series of harmonics that are the sum and difference frequencies of the two input signals. 

We are basically combining two frequencies to create sidebands.

This technique is commonly used in electronic music synthesis and sound design to create complex, dissonant, metallic or bell-like sounds and timbres.

The ring modulator on the ARP 2600 is particularly interesting because it can also be used as a frequency multiplier. By sending a single frequency into one input of the ring modulator and adjusting the frequency of the other input, you can create complex and evolving harmonic patterns and evolving sounds.

The left and right inputs are normalised to VCO 1 & VCO 2

though these signals can be over-ridden by patching into the jacks.

You can also use it as a very unusual CV mixer.

Notice the Audio/DC switch.

The Ring-Mod module is normalised to both the VCF and VCA.

This means you can have both a filtered and a non-filtered ring-modulated signal

Patch 1

Since VCO1 & 2 are already hard-wired to the ring-mod its 

good to start experiments just by tweaking the frequencies of the two VCOs.

You don't have to do any patching.

Just open up the connection to the VCA and listen.

Results can be pretty wild and unpredictable.

It's a sound designers dream. ;-)

Patch 2

Adding different wave-forms into input 2

Play around with the Audio/DC switch.

You can also change one of  the inputs to a LFO, and keep the other as audio.

Patch 3

Using the ring modulator to create CVs

Set both inputs to Low frequencies.

Thus the Ring Mod won't produce sound ... instead  it will produce control voltages.

So the ring modulator is now converted into an unusual CV mixer.

It's output can now be plugged into anywhere that accepts CVs.

In this example the inputs to the RM are LFOs.

The output of the RM is modulating the Fc of the filter.

Patch 4

Ring Mod as a VCA

The ARP's ring mod is kind of "super" vca because it is a "4 quadrant" multiplier vs the normal VCA which is a 2 quadrant multiplier .

Set the control switch to DC.

I'm using noise as a sound source.

Plug this into the left input

The right input are various waveforms ... all LFOs 

The output of the ring mod is plugged straight into the mixer.

+ ARP 2600 - Envelope Generators

+ ARP 2600 - Sample and hold (& electronic switch)