If nothing’s plugged into your keyboard’s footpedal jack (or there’s no pedal feeding MIDI continuous controller data to a soft synth), you’re passing up one of the best ways to create more expressive keyboard parts. Many synths let you assign an external footpedal to any parameter, including effects. But which parameters are good targets for pedal control? Well, since you asked . . .
1. Volume and Filter Cutoff
These are the obvious choices, so let’s move on.
2. Distortion Drive
Distortion is an increasingly popular onboard effect for synths, but take a cue from guitarists and differentiate between rhythm and lead. Nothing says “pay attention to this part!” like putting the pedal to the metal, and going from a somewhat soiled sound to overloaded screaming.
3. Oscillator Fine Tune
You know that cool flanging effect that happens when you detune one oscillator compared to another? Use a pedal to vary the fine-tuning, therefore controlling the beating between the two oscillators. Faster beating gives a more intense feel, while slowing, rolling flanging sounds more ambient/relaxed.
4. Amplitude Envelope Decay
This is particularly effective for percussive synth-bass parts (and open/closed high-hat with drums). The parameter you’ll want to control depends on how the envelope generator works for percussive sounds. With an ADSR envelope, set Attack and Decay to minimum, Sustain to full on, and tie Release to the pedal. Changing the release can change the sound continuously from really tight, percussive effects to longer sounds with longer decays.
5. Sub-Octave Level
If you don’t have a sub-bass option, add an oscillator tuned an octave lower and set to a simple waveform (sine or filtered triangle). Assign the pedal to the sub-octave level, and add in some beef when the song needs extra gravitas (the bridge and chorus love this kind of treatment).
6. High Frequency EQ
Most synth effects sections have some kind of high-frequency EQ, like a shelving EQ, parametric, etc. Have the pedal control the high frequency level; with the highs pulled back just a bit, a digital synth will sound more “analog” and often, sit better in a track. On the other hand, when the synth needs to be more prominent, increase the highs. If there’s no dedicated EQ but there’s a lowpass filter in the signal path, you can accomplish the same general effect by using the pedal to raise or lower the filter cutoff slightly.
7. Delay Feedback and/or Mix
Long, languid echoes are great for accenting individual notes, but might get in the way during staccato passages. Controlling the amount of echo feedback lets you push the number of echoes to the max when you want really spacey sounds, then pull back on the echoes for tighter, more specific effects; setting echo to minimum usually gives a single slapback echo instead of a wash of echoes. An even cooler trick is to increase the delay amount and feedback at the same time so that as you push down on the pedal, you not only get more echoes— they’re also louder.
DON’T FORGET THE OPTIONS!
It would be boring if pedals always had to change a parameter from the absolute minimum to maximum setting— for many effects, you want finer control, where the pedal covers a smaller range.
Fortunately, devices that accept external parameter control usually let you adjust the incoming control signal’s amplitude and polarity. Amplitude determines the overall range; some synths even let you specify a minimum and maximum amplitude (Example 1). This corresponds to pedal all the way back and all the way forward, respectively.
Polarity sets whether the incoming signal adds to, or subtracts from, the target parameter value. For example, when controlling filter cutoff, pushing down on the pedal with positive polarity would likely raise the cutoff frequency, while negative polarity would lower the filter cutoff from its existing value. With a minimum/ maximum value option, you’d set the minimum value higher than the maximum to reverse polarity.