Sidechain ducking routes a control signal to a dynamics processor to carve space for a competing track

The practical pattern of sidechain ducking is always the same: identify the signal that should control the ducking, then route it to the sidechain (key) input of a dynamics processor placed on the track you want to duck. The processor type is chosen for the job — a broadband compressor to duck whole-track level, a dynamic EQ or multiband compressor to duck only a masking frequency range, or a gate whose opening is gated by a cleaner control signal. What changes across uses is the source, the target, and the processor type; the routing logic is invariant.

Examples

Drum overhead bleed: put a compressor on the overheads, send the snare close mic to its sidechain — overheads attenuate each time the close-miked snare fires. Bright guitars masking a lead vocal: a dynamic EQ on the guitars with the vocal on its sidechain mellows only the vocal’s frequency range.

Assessment

For (a) bright guitars masking a lead vocal and (b) excessive bleed on a kick-out track, describe the sidechain routing needed and which dynamics-processor type to use, and justify the processor choice.