Making the Most Of Your Mixer
MG16/4, MG12/4
10
Where Your Signal Goes Once It’s Inside the Box
At first glance the block diagram of even a modest mixer can look like a space-station schematic. In reality,
block diagrams are a great aid in understanding how the signal flows in any mixer. Here’s a greatly simplified
block diagram of a generic mixer to help you become familiar with the way these things work.

2-1. Greatly Simplified Mixer Block Diagram

■Input Channel

1Head Amp

The very first stage in any mixer, and
usually the only stage with significant
“gain” or “amplification.” The head
amp has a “gain” control that adjusts
the mixer’s input sensitivity to match the
level of the source. Small signals (e.g.
mics) are amplified, and large signals
are attenuated.

2Equalizer

Could be simple bass and treble con-
trols or a full-blown 4-band parametric
EQ. When boost is applied the EQ stage
also has gain. You can actually overload
the input channel by applying too much
EQ boost. It’s usually better to cut than
boost.

3Channel Peak LED & Fader

The channel peak LED is your most
valuable tool for setting the input “gain”
control for optimum performance. Note
that it is located after the head amp and
EQ stage.

■Master Section

4Summing Amplifier

This is where the actual “mixing” takes
place. Signals from all of the mixer’s
input channels are “summed” (mixed)
together here.

5Master Fader & Level Meter

A stereo, mono, or bus master fader and
the mixer’s main output level meter.
There could be several master faders
depending on the design of the mixer—
i.e. the number of buses or outputs it
provides.
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Input Channel Master Section
Signals from the mixer’s
other input channels (if
they are assigned to this
master output or “bus”).