Free Processors

Gozintas

A synthesizer has modules that generate sounds (like oscillators), modify sounds (e.g., filters), and control sounds (LFO, envelope). An external input replaces (or supplements) the sound-generating modules, so the audio can be processed by other synth elements. I first saw this with Native Instruments’ B4 organ, which lets you use the rotating speaker as a separate plug-in. And on Korg’s Legacy Collection, you can access the filter of their virtual MS-20.

With software hosts, the instrument itself may show up on a list of virtual instruments, while the instrument effects show up on a list of audio processing plug-ins. However, there are exceptions. For example, with Sonar, if you insert any external input-friendly Arturia synth into a track’s effects/instruments slot, the external input is automatically available for any signal present on the associated track.

Another example: With Creamware’s Minimax, the audio input is a patch point within the SCOPE system. Thus, you can feed it from any output within SCOPE (including sequencer host tracks); its output can be folded back into a host input, sent to the SCOPE mixer, or routed directly to an output.

Let’s Get Hands-On

One of my fave applications is sending a signal through a highly resonant filter, then playing the filter frequency from a keyboard — sort of a “manual sample-and-hold” effect that imparts a sense of pitch. Figure 1 shows how to set up the Minimax to do this, but the same principles (and even control settings) apply to Arturia’s Minimoog V.

Mondo Modular Processing

Modular synths (e.g., Arturia Moog Modular V 2 and ARP 2600V, Creamware Modular 2 and III) are great processors, thanks to their wealth of modules and routing possibilities.

Figure 2 shows an ARP 2600V preset (for a more detailed view, see a full-size version at www.keyboard mag.com). The input signal goes into a ring modulator (the other ring modulator signal comes from VCO 2). The ring modulator out feeds the filter and VCA ins. Both the filter and VCO 2 are modulated by a sample-and-hold module (see “Jargon Jockey”), synced to tempo. The filter out then goes to the VCA, which is triggered by an envelope follower that derives its control signal from the external input. The resulting sound is pretty nuts — check out the audio example.

Bottom line: If your soft synth accepts external inputs, here’s your chance to stretch beyond the standard delay, reverb, chorus, etc.— and make some truly original sounds in the process.