5. Gain Structure 201

Gain structure, the most misunderstood concept in professional audio engineering.

This is an overview of the logic of Gain Structure to ensure proper throughput in any system. Gain structure is defined as a balance of signals throughout the signal chain of the entire sound system. The signal chain starts at the input stage of an audio mixing console. It could be a microphone, or it could be an iPod that is connected. One type of signal requires high amounts of gain added to it, whereas the latter requires relatively little added gain compared to the microphone.

There are many "gain stages" in a mixing console. Just as there is an input amplifier for the microphone, an output signal is fed from the amplifier to the next gain stage. Balancing the inputs and outputs of all the gain stages in a console is achieved by using metering. The best consoles allow you to meter levels at any spot in the signal chain. This is crucial to what I call Relative Audio Balancing. Voices and instruments vary wildly in timbre and pitch, and making adjustments that make individual sounds relative to one another involves adjusting the gain at different points. Dynamic processing such as limiting or compression is designed to help the engineer keep levels within the acceptable design limits of the circuitry. Input clipping, over-saturation, phase cancellation, and phenomena relative to audio signals "in the wire" are to be avoided at all costs. In this course, we will learn how to manage gain structure effectively.