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Understanding Console Signal Path

Recording and PA consoles operate at a nominal level of +4dBu, while microphones operate at a level

of typically about -50dBu. Microphone signals must be amplified to the appropriate level for a console

to process it properly. If a signal is not raised to the appropriate level, the signal will be "masked" by

the console's internal noise, especially when one tries to increase the level of a low signal using the con-

sole fader or gain knob. All consoles have a preamp (usually labeled "Gain") as the first stage of an input

strip, allowing the user to boost a signal to an appropriate level before the other processes of the input

strip act upon the signal (EQ, dynamics, panning, etc.) Unfortunately, console preamp circuits are often

not given enough room on the circuit board, or high-quality parts. It is for this reason that outboard pre-

amps have become so popular. See Figure 1 below for a typical input strip's signal flow.

1/4"line

input

XLR mic

input

1/4" output

1/4" input

Equalization

Mic / Line

Switch

Phase Rev.

Switch

Send

Inserts

Return

EQ in/out

Aux Sends

1/4" output

Direct Out

Gain

- Preamp

Lo-Cut

Filter

Buss to

Main Outputs

and Group

Routing

Pan

Mute

Switch

switch

Fader

Introduction

786

Figure 1: Signal flow of

Typical

Console

Strip.

The gain, or preamp stage

occurs before all audio-

critical processes act upon

the incoming signal. The

preamp's "color" is then

processed as part of the

signal.

The only processes ahead

of the preamp stage are the

input selection stage, and

the phase reverse switch.

Input