A stage monitor system is a separate sound system pointed at performers, providing individualized mixes

A stage monitor (foldback) system is independent of the house PA system. Its loudspeakers are aimed at the performers on stage to allow them to hear themselves and each other. A dedicated monitor console (usually positioned at stage-side) provides separate output mixes for each performer or group of performers. Each mix is customized to what that performer needs: a vocalist might need mostly vocal and piano; the bassist needs kick drum and bass guitar. Monitor quality directly affects stage performance quality; poor monitors cause performers to strain, miss cues, or play out of tune. Monitor sound also inevitably spills into onstage microphones and out to the audience, affecting house sound quality and feedback susceptibility.

Examples

A touring band with 6 performers might have 6 separate monitor mixes: lead vocal, background vocals, drums, bass/guitar, keys, and guitar. The monitor engineer at stage-side manages all 6 mixes independently of the FOH mix.

Assessment

Why does monitor quality affect house sound quality even though the two systems appear independent? List two specific mechanisms.