Sound Design Workshop: What's Your Number?

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FIG. 1: This Numerology Stack uses an LFO (top) and a CV lane of a MonoNote sequencer (bottom) to modulate the sample start and loop boundaries of the speech clip in the Sample Synth module (middle). The MonoNote also sets the playback pitches and step lengths.

My first encounter with a step sequencer was the 960 module in a Moog modular system. It provided three rows of eight knobs to create three control-voltage sequences that you could cable to affect other Moog modules. It also had individual trigger inputs (to select steps), gate outputs, an internal clock, and sundry special features. Creating note sequences was not the 960''s primary purpose, and it presented some challenges, not least of which was tuning.

The note-based step sequencers in modern synths, samplers, and drum machines tend to obscure the considerable sound-design potential of step sequencing. The most robust environment for that on the Mac I''ve seen is Numerology 3 from Five12 ( It offers more than 50 modules for generating and processing notes and control signals. I''ve used Numerology in my examples, but you can adapt most of these techniques to any step sequencer that has controller lanes and flexible signal routing.

Numerology''s Sample Synth is a good place to start. It holds a single sample, changes pitch by changing playback speed, and lets you modulate the sample start, as well as the loop start and end points. In addition to loading samples, you can create synthesized speech clips using Apple''s OS X Speech Synthesizer; just click Sample Synth''s Speak button, type in some text, and choose a voice.

Figure 1 shows a setup I often use to mangle speech clips (see Web Clip 1). A sample-and-hold LFO controls the sample start, a MonoNote sequencer plays the notes, and a CV lane of the same sequencer sets the loop end. The Scale and Offset module converts the loop-end position to an offset from the sample-start position, and the ParamMod module routes it to the Sample Synth.

The ParamMod module gives you instant access to almost any parameter in an AU plug-in or other Numerology module—no MIDI Learn or special setup required. To route a modulation source (LFO, envelope generator, sequencer CV lane, etc.), select the target and parameter from drop-down menus. (Many of Numerology''s CV-generator modules have those menus built in.)

You can add ParamMod modules as needed to target multiple parameters. Use that to apply the same modulation to different AU synths and effects, as well as to multiple parameters of the same device (see Web Clip 2). Once you''ve set up a modulation scheme, save the Stack with or without the AUs. Then you need to re-create only the modulation routings to apply the same modulation in different setups.

You can forgo step sequencing and just use Numerology as a modulation source for instruments played in real time or from MIDI tracks in your DAW. You can route incoming MIDI directly to any AU plug-in. In addition, the MIDI-to-CV module extracts note number, gate, velocity, pitch-bend, aftertouch, and four MIDI CC streams from incoming MIDI data and provides them as separate outputs, which you can then route to control other plug-in or Numerology parameters. Use the gates to start and stop or advance CV sequencers or trigger envelope generators, and use the other outputs for direct control or to scale the effect of other Numerology modules.

Len Sasso is a freelance writer and frequent EM contributor.