Quad Lopass Gate

Model 292C is a later revision of the 292 which can be remotely switched between Lopass/both/gate by a Buchla 300.

Four independent gates with selectable amplitude-dependents spectral characteristics. Knob settings and applied control voltages determine levels and cutoff frequencies. A summed output facilitates voltage controlled mixing.

The Model 292, with the capability of simulating the spectral and amplitude changes that accompany a receding sound source, is one of several Electric Music Box modules that can deal with spatial localization and movement. [Others are the Model 227 System Interface and the 285 Frequency Shifter/Balanced Modulator (for Doppler shift).]

Frequency domain gating can impart a dynamic tonal variation to sounds that gives the listener a sense of absolute loudness. This quality is characteristic of all acoustic instruments (the harder you strike, pluck, or bow, the richer the overtone structure), but has been lacking in electronic instrumentation.

http://www.buchla.com/historical/b200/292-lopassgate.html