West Music Staff Blogs

On the typical mixing console, each channel strip includes a knob at the top that behaves like a volume control.

Meanwhile, the fader at the bottom of the channel strip also controls volume.

Why are there two controls that appear to do the same thing?

You’ve probably heard sound systems that issue a fairly audible hiss in an otherwise quiet room, as well as distortion when someone speaks loudly or when a singer gets aggressive. Both of these problems are usually caused by improper gain structure at the console.

In typical applications, several different types of microphones (and direct inputs) are used.

For example, at a church a pastor wears a wireless lavalier mic, the pulpit has a condenser mic, the praise team has four dynamic vocal mics, and there is one acoustic guitar pickup with no preamp and one electronic keyboard.

All of these devices send a different signal level to the console. The guitar pickup and the dynamic mics send a relatively weak signal.

The keyboard sends a strong signal because it’s a powered device. And the wireless and the pulpit mics are somewhere between the two.

A Related Idea All electronic devices have a “noise floor.” Whether it’s a $50 component or a $50,000 component, all produce a certain amount of noise.

Most manufacturers of audio equipment attempt to maximize audio signal while holding noise floor to a minimum. The difference in level is the “signal-to-noise ratio” seen on manufacturer data sheets. (Typically, a 90 dB ratio is considered to be “studio quality.”)

Read More from Jon Baumgartner's article at: Pro Sound Web: News & Information for the Audio Professional.