Defined Sound System Components (below)
Ground - Quick Definitions
Earth Ground / AC Ground
The Difference Between Neutral and Ground
The Case of Voltage Between Neutral and Ground
Three Phase AC Power
Chassis Ground
Audio Ground/Reference/Common / Circuit Ground / Signal Ground / Zero Volt Reference
Earth Ground Referencing of the Audio Ground / Zero Volt Bus
For the purposes of discussion on PA systems and sound system grounding, I will define a professional transportable sound system as typically having;
Its own portable Alternating Current (AC) power distribution system specified to be capable of providing enough current to power the entire sound system and onstage musical equipment (backline).
Separate Front of House (aka FOH) and onstage Monitor audio mixing consoles of 16 to 48+ channels linked to a common microphone splitter system located on stage. Each console would be connected to the splitter via two conductor shielded twisted pair mulitcore cable dedicated as the input "snake". A multipin connector for this purpose is typically used but is not pertinent to grounding unless it is poorly constructed or shorts the shields together which is not recommended.
Auxiliary racks at both Front of House and Monitors which would consist of either equalizers, insertable gates and/or compressors, digital effects units, or small format recording and playback devices. Some or all of these racks would also connect to their respective mixing consoles with multicore two conductor shielded twisted pair cable (multipin connectors again are optional).
Separate amplifier rack(s) for stage left and stage right speaker systems located on each side of the stage and fed from the Front of House by a stereo multiway electronic crossover - digital or analog.
The system EQ, system crossover, and associated loudspeaker processing would be located at the Front of House in a separate "Drive" rack and would connect to the stage left and stage right amplifier racks via a dedicated multicore two conductor shielded twisted pair cable (multipin connectors again are optional). Most FOH engineers I know prefer the system crossover at the FOH position unless they're using proprietary locked crossover systems, like Meyer processors where one of the few things you can adjust is the input trim, or digital crossovers remotely controlled from the FOH via computer.
[ Ground ] [ AC Ground ] [ Neutral ] [ N>G voltage ] [ 3ø AC Power ] [ Chassis Gnd ] [ Audio Ground ] [ Referencing ]