Bass, mid, top and gain

What this lesson teaches

Four controls per channel, and most beginners can work out roughly what they do by turning them. Knowing the frequencies behind them is what lets you use them deliberately.

The three bands

Low, or bass. Roughly 20 Hz up to about 150 Hz. Below about 20 Hz you stop hearing and start feeling, which is why a big system is physical. This band is the kick drum and the bassline - his description is the boom you hear when lightning goes off.

Mid. From about 150 Hz upwards. Vocals live here, and so do guitars, the melody and most instruments. Take the mid out and the track loses its tune while keeping its weight and its sparkle.

High, or treble, or top. Hi-hats, cymbals, hand claps, and the air that makes a recording sound open. Take it away and everything sounds muffled, as though it is playing through a wall.

He demonstrates each one by removing it, which is the right way round: you learn far more about what a band does by taking it out than by boosting it.

Balance

Pans that channel between the left and right speakers. Normally it belongs in the centre and stays there. It is occasionally useful for diagnosis - if you suspect one side of a system is dead, panning a channel hard over tells you quickly.

Gain

The knob above the EQ, and it does a different job entirely: it sets how loud the signal arrives inside the mixer, before anything else touches it.

Its purpose is to make different sources match. His example is exactly right - an album track cut quieter than a 12-inch single will come in several decibels down, and without gain you would be riding the fader all night to compensate. Set the gain so every track arrives at the same level and the faders mean the same thing each time.

The starting positions, and the reason behind them

His recommendation: mid and treble at twelve o'clock, bass slightly below, around eleven. And he is pointedly rude about DJs who run everything boosted, promising to explain why in the next video.

The explanation is worth having now, because it governs how you should use an EQ for the rest of your life.

An EQ boost is gain. Turning the bass up does not politely emphasise the bass - it adds level to the part of the signal that is already by far the loudest, which eats your headroom and pushes the channel towards distortion. The lights look exciting and the sound gets worse.

A cut costs nothing. So the habit to build is: take away what you do not want rather than add what you do. If a track needs more bass relative to its mids, pull the mids down and turn the channel up, rather than pushing the bass.

And parking the bass a little below centre at the start is not a tone preference. It is leaving yourself somewhere to go - so that when you do want to push the bass for a moment, there is room to do it without going into the red.