Grooveline - North East Function Band

Input level and Equalization for Live Sound

Input level should be the first port of call for a sound person. If an input level has a hiss or is clipping then the overall sound from a PA could be compromised and could lead to further complications such as no headroom and feedback.

On a lot of mixers nowadays you can monitor the PFL (Per Fader Level) on each channel. This is where you need to check that the level is not peaking/clipping, usually shown buy a little light next to the gain knob and/or on the output level of the desk and that there is no hum or buzz coming from that particular input. A good set of headphones is very useful for this, Sennheiser and Beyer dynamic are a couple of good names to use.

If you have an input level that is peaking even with the gain turned completely down then you need to get a Di (Direct input) box with a gain cut. This is known as attenuation but is commonly revered to as a pad. Di boxes are usually used to convert line level (+4 dB) to mic level (-10) so most come with a -20dB pad. Flick this switch and add gain to suit.

When you have a good clean input level start thinking about the sound of the instrument the input level is concerning. A good way of thinking about this is frequency ranges. Eh, you may say but if you think of a drum kit which consists of a bass drum, floor tom, mid tom, hi tom, a snare drum, hi hats, crash and ride cymbals it sort of tells you what frequencies they use.

Bass drum gives a bass sound so this input could have to hi and some of the mid frequencies cut out of it and maybe a low frequency boost. It’s best when you first start gigging to get the musician to play each bit of equipment so you can listen to how it sounds flat (with no EQ) then think of how you what it to sound and try to get that sound using the EQ on your desk.

Also by cutting the top end out of a bass drum input you’ll be helping to stop spillage (when a microphone picks up other instruments other than the one it should) from other drums to the bass drum mic.

This way of thinking works but can be improved with a better EQ section. If you have a sweeping frequency knob then add a lot of gain to it and sweep through all the frequencies to see how it effects the sound then chose either a sound you like and boost it or a sound you don’t like and cut it.