The modulation wheel on your synth doesn’t have to control vibrato. I often use pitch-bend as vibrato, which frees up the mod wheel to lead a much more interesting existence—or add an effect along with vibrato. The key to mod wheel fun is controlling multiple parameters. For best results, your synth needs two control parameters between the mod source and destination: level to adjust modulation strength, and offset to provide an initial, fixed modulation value. Now, try these tips on for size . . .
Tone control. Particularly with bass, I like rolling the mod wheel forward to reduce highs (e.g., by lowering a 12dB- or 6dB-per-octave filter’s cutoff frequency) and simultaneously increasing gain to compensate for the lower level. Or, increase the level of a sub-octave sine wave while the filter cutoff lowers, thus giving a super-bass sound (see Figure 1 below). Here’s a related trick: Adding an octave-lower sine wave to an ethereal female choir gives the illusion of adding some male voices to the choir.
Fig. 1. Arturia’s Prophet-5 is using MIDI learn so the mod wheel lowers the filter while it’s raising the level of oscillator B, which is set to a sub-octave.
Reinforce the fundamental. A variation on the above is controlling the level of a sine wave tuned to the preset’s fundamental; bring in a hint of sine wave for a deeper, more powerful fundamental on lower notes. Try this on a piano’s lower octaves if you want it to dominate a track, but note that a little reinforcement goes a long way.
Distortion. Some synths let you control signal processor parameters with modulation sources. With distortion, use offset to set a minimum drive amount, and the modulation wheel to increase the drive amount. Also, apply a little negative modulation to the output level so that there’s not a huge volume change when going from minimum to maximum drive.
Guitar-like feedback. Guitarists often sustain a note at high volume, inducing a second tone that’s typically a couple of octaves and a fifth above the fundamental. Tune an additional sine wave oscillator appropriately, and control its level with the mod wheel. To be more guitar-like, add some vibrato as the “feedback” appears, and pull back slightly on the fundamental’s level (see Figure 2 below).
Fig. 2. Steinberg’s Retrologue sets up modulation to bring in oscillator 2’s “feedback” sound, while adding vibrato and reducing the level of oscillator 1.
Fun with melodic percussion. Pitched percussion (e.g., cowbell, clave, struck metal pipe), can add dramatic attacks if you transpose them up an octave or two and mix them in subtly with the mod wheel when appropriate. Also try tying modulation to filter so that increasing the pitched percussion’s level lowers the filter cutoff to take a bit of the edge off the percussion sound.
Major meets minor. Got three oscillators? Create a chord with the root note and the fifth, but use the modulation wheel to control the pitch of the third—forward for major and back for minor.
Waveform/patch morphing. At its most basic, this technique controls the level of two oscillators so that as one goes from full off to full on, the other goes from full on to full off. But there are rich possibilities, like morphing between a cello and sawtooth wave so you can go from more realistic to more synthetic, or combine the two—or even morph between patches (see Figure 3 below).
Fig. 3. In Cakewalk Rapture, Volume 1 controls a percussive sound, while Volumes 2 and 3 control a pad sound. Adding modulation fades out Volume 1, raises Volumes 2 and 3 to compensate, and pitch-modulates the LFO to animate the pads.