Updated October 2026 · Audio basics for beginners
EQ, short for equalisation, boosts or cuts the level of particular frequencies. It shapes the tone of a sound. For speech, small cuts can reduce muddiness or harshness, and small boosts can add clarity or warmth. Use EQ gently, make one change at a time, and check it against the original.
Equalisation, usually called EQ, is one of the most used tools in audio. It changes the balance of frequencies in a sound, making it brighter, darker, warmer or thinner. Beginners often reach for EQ to fix every problem, and they end up with a voice that sounds artificial. Used gently, with a clear purpose, EQ is a powerful way to shape a voice. Used heavily, it damages the sound.
This post explains what EQ does, the frequency areas that matter most for speech, a simple way to find problems and the restraint that keeps the voice natural.
Every sound is made of many frequencies, from the deep bass to the high treble. EQ lets you raise or lower the level of a band of those frequencies. A boost makes that band louder, and a cut makes it quieter. The range of frequencies affected depends on the filter, and the width of the band depends on its setting.
The effect is a change in tone. A voice can sound fuller, thinner, closer or more distant, depending on which bands are changed.
A high-pass filter removes the lowest frequencies, which often carry rumble, handling noise and room boom. For most speech, a gentle high-pass filter in the lower range is a safe first step. Set it high enough to remove the rumble, but low enough that the warmth of the voice remains.
A few decibels of change is often enough. If you need more, look for the cause of the problem first. A voice that is too thin may be recorded too far away. A voice that is harsh may be too close to a bright microphone. EQ can help, but it works best on a good recording.
A phone recording often needs less EQ than beginners expect, because the phone’s own processing may already shape the sound. Start by listening to the raw file on headphones, and identify the one problem that bothers you most, such as rumble, boxiness or harshness. Fix that first, then listen again before adding anything else. Each extra change adds another layer that can make the voice sound unnatural.
If a phone recording is thin, the cause is usually distance or room. EQ can add some warmth, but it cannot replace a closer position. Record again closer if you can, and keep the EQ as a finishing touch.
Sweeping is the fastest way to find a problem band. Boost a narrow band by a few decibels, move it slowly across the range, and stop where the voice sounds most unpleasant. Then cut that band slightly, and check whether the voice regains its clarity. A narrow cut removes the problem with the least damage to the rest of the sound, which is why it usually beats a broad, gentle change. Write down the frequency you cut, so the same problem can be found quickly in the next recording.
The frequencies given here are approximate, and they vary between voices. The right EQ for one voice may be wrong for another. Use the ranges as starting points, and adjust by ear. Some problems, such as a noisy room, cannot be solved by EQ at all.
Listening decides EQ, not the curve on the screen. The Vocal Checker shows clipping, noise and level problems in a recording you own, and the Tunedzy Go page covers cleaning a phone recording. For the tone problems in voices, read the tinny voice post and the harsh voice post in this series.
Spot clipping, noise, rumble and level problems. Runs in your browser, nothing is uploaded.
A gentle high-pass filter to remove rumble and handling noise.
A few decibels is usually enough. Make small changes and compare with the original.
Only partly. Distance changes the sound in ways EQ cannot fully restore.
Usually clean first, so the EQ shapes the clean signal rather than the noise.
