Live Sound EQ Cheat Sheet: Frequencies by Problem

Live EQ is a different discipline from studio EQ, and frequency charts written for the studio mislead people who take them to a venue. Live you are cutting more than boosting, working faster, fighting a room and constant microphone bleed, and making decisions that have to be right the first time. This is a problem-first reference: you hear something wrong, you find it here, you know roughly where to reach.

Start with the rule that outperforms every chart. High-pass everything except kick and bass, aggressively. Vocals at 100 to 150 Hz, snare around 150 to 200 Hz, guitars around 100 Hz, hi-hat and overheads higher still. Microphones capture low-frequency energy that the source never produced, mostly stage rumble and bleed, and removing it cleans up more mud than any surgical cut you will make afterward. It also buys measurable gain before feedback.

Below 100 Hz: rumble and thump. Problems here are stage vibration, handling noise, and wind on outdoor stages. This range should be empty on everything except kick, bass, and floor toms. If a vocal channel has energy here it is contamination, not content.

100 to 250 Hz: mud and boom. This is where a live mix dies most often, because every source has energy here and it accumulates. When a full band sounds thick, congested, and indistinct, this is almost always the range. Cut it on the sources that do not need it rather than boosting elsewhere. Rooms with hard rear walls exaggerate this range further, and a console at the back wall will underreport it.

250 to 500 Hz: boxiness. A cardboard, closed-in quality on vocals and snare lives here. Small rooms emphasize it. A moderate cut around 300 to 400 Hz opens up a vocal that sounds like it is coming from inside a box, and it is one of the most reliable single moves in live sound.

500 Hz to 1 kHz: honk and nasality. Vocals that sound nasal, guitars that sound like a telephone, and general midrange fatigue sit here. This is also a very common feedback region for vocal microphones, so a cut here often does double duty: it improves tone and it buys headroom on the wedge at the same time.

1 to 4 kHz: presence and harshness. This is where intelligibility lives, which makes it dangerous to cut casually and painful to boost casually. Consonants and vocal clarity come from roughly 2 to 4 kHz, and so does listener fatigue. If the vocal is present but tiring, a small cut near 3 kHz usually helps more than a broad reduction. If the vocal is buried but loud, the problem is usually competing energy here from cymbals and guitars rather than a lack of vocal.

4 to 8 kHz: sibilance and edge. Harsh S sounds, piercing hi-hat, and cymbal glare. Live, this range is worsened by both close microphone technique and bright PA systems. Narrow cuts work better than broad ones, because a broad cut here makes the whole mix dull while a narrow cut removes the specific offense.

Above 8 kHz: air, and the region audiences absorb. Adding a little here can open a mix in an empty room and then vanish once the room fills with people, because bodies absorb high frequencies. Expect to add a small amount after the room fills rather than committing to it during an empty-room soundcheck.

How to use this under pressure. Do not sweep hunting for problems during a show, because sweeping with a boost is audible to the audience and takes time you do not have. Instead, name the problem in words first (muddy, boxy, nasal, harsh, piercing), map the word to the range above, and make a decisive cut of 3 to 6 dB. Live cuts are bolder than studio cuts. A 6 dB cut that would be heavy-handed in a studio is routine here.

The skill under the chart is recognition, not memorization. A chart tells you where to reach once you have named the problem, but naming it is the part that has to happen in a second. That recognition is trainable in isolation, away from a venue, and it is the difference between an engineer who fixes a ringing frequency in two seconds and one who sweeps for thirty.