Equalizer

An equalizer changes how loud different frequency ranges are relative to one another. Turning down 350 Hz makes a recording less boxy; turning up 3.5 kHz makes speech cut through; turning up 60 Hz adds weight to music.

It is the single most useful audio tool for fixing recordings that are technically fine but sound wrong — a voice memo that booms, a song that feels dull on laptop speakers, a podcast that is hard to follow.

This one is a six-band graphic EQ, which is the format most people can use without training: fixed frequencies, one slider each, and a live preview so you can trust your ears instead of guessing.

The most useful habit in equalization is counter-intuitive: when something sounds wrong, reduce what is competing with it rather than raising what you want to hear.

There are two reasons. The first is headroom. Every boost raises the peak level of the file, and most finished audio sits close to maximum already — so boosting pushes it into clipping, which sounds like crackle and cannot be undone. Cutting moves the balance the same way and lowers the peak.

The second is that human hearing judges balance, not absolutes. A voice that is buried under a boomy low end sounds clearer once the low end comes down, even though nothing about the voice changed. Turning the voice up instead makes everything louder and no clearer.

The other thing worth internalising is that EQ moves are small. Three decibels is a clearly audible change; six is a large one; twelve is an effect rather than a correction. Sliders that are all pushed to the ends generally mean the problem is somewhere else — the wrong microphone, the wrong distance, or a room with hard walls.

Finally, listen on more than one thing. Laptop speakers cannot reproduce 60 Hz at all, so a bass adjustment made on them is guesswork. If a mix has to work everywhere, check it on headphones and on a phone speaker before exporting.