A module designed for a modular synthesizer that implements a "typical" synthesizer voice. A voice module usually consists of:
- One or two voltage controlled oscillators
- A voltage controlled filter
- A voltage controlled amplifier
- An envelope generator
- A low frequency oscillator
- Common additions: a mixer, a headphone amp, a noise source, and a MIDI interface.
In keeping with the modular principle, a voice module will generally have patch points for each of the functions that the module contains. These might be scattered around the panel near the controls for the functions that the patch points access, or they may be grouped together off to one side. Typically, there are some normalled connections inside the module that are interrupted by plugging in patch cords.
A voice module can be a cost-efficient way of acquiring basic functions when starting a modular synth, as opposed to buying each of the functions as separate modules, although there is often a cost in patching flexibility. Voice modules are also used by modular synth performers who want to be able to play polyphonically, in order to save space and keep costs under control.