A suboctave refers to a signal or frequency that is one or more octaves below a given input signal or frequency. This concept is often employed in the context of oscillators, frequency dividers, or suboctave generator modules.
When you create a suboctave, you are essentially halving the input frequency for each octave you go down. For instance, if the input frequency is 440 Hz (A4), its suboctave one octave below would be 220 Hz (A3), and two octaves below would be 110 Hz (A2).
Suboctaves are commonly used in synthesis to add depth and richness to a sound by reinforcing its harmonic content with lower frequency components. This technique can create a thicker and fuller sound, which is especially useful when designing bass sounds, leads, or complex textures in a modular synth patch.