Layering detuned oscillators models the multiple resonant modes of a drum membrane

A real drum membrane does not vibrate at one frequency. It supports multiple modes of vibration simultaneously — axisymmetric modes, nodal diameter modes — each at a different frequency (approximately inharmonic ratios). A single sine oscillator captures only the dominant mode; adding a second sine at a different tuning (slightly detuned or at a musically related interval) approximates the richer modal spectrum of the real instrument. Each layer can have its own shorter or longer envelope to reflect that different modes decay at different rates. The result is a drum sound that breathes and has internal movement rather than the static quality of a single-oscillator patch. This approach is used in physical modeling as an approximation to finite-element membrane simulation.

Examples

808 kick: copy oscillator A settings to oscillator C (parallel chain), then detune C by a few semitones and shorten its envelope — the fundamental stays but a second mode adds body and movement.

Assessment

Given a single-sine kick patch, add a second detuned sine and describe how the perceptual character changes with detuning intervals of +2, +7, and +12 semitones.