Although some instruments call for specific EQ (equalization) guidelines, you should consider some general issues when EQing, regardless of the instrument involved. When it comes to the audible frequency spectrum (which is generally about 20 Hz to 20 kHz), certain frequencies always have certain characteristics. The following describes these frequencies.
| Frequency | Sound Characteristic |
|---|---|
| 20–100 Hz | Warms an instrument or adds boominess to it |
| 100–200 Hz | Is muddy for some instruments but adds fullness to others |
| 350–450 Hz | Sounds boxy |
| 750–850 Hz | Adds depth or body |
| 1–2 kHz | Adds attack or punch to some instruments and creates a nasally sound in others |
| 2–5 kHz | Increases the presence of instruments |
| 5–8 kHz | Sounds harsh in some instruments |
| 8 kHz and above | Adds airiness or brightness to an instrument |
You’re generally better off cutting a frequency than boosting one. This thinking goes back to the early days of analog EQs, which often added noise when boosting a signal. This can still be a factor with some digital EQs, but it is much less of an issue.
The exact frequencies that you end up cutting or boosting depend on the sound you want, the tonal characteristic of the instrument, and the relationship between all the instruments in the song. The following table shows an overview of frequencies to cut or boost for each instrument. You may not want to follow all the suggestions. Just choose the ones that help you meet your goals.
| Frequency | Adjustment (dB) | Purpose |
|---|---|---|
| Vocals | ||
| 150 Hz | +2–3 | Adds fullness |
| 200–250 Hz | –2–3 | Reduces muddiness |
| 3 kHz | +2–4 | Adds clarity |
| 5 kHz | +1–2 | Adds presence |
| 7.5–10 kHz | –2–3 | Cuts sibilance |
| 10 kHz | +2–3 | Adds air or brightness |
| Electric guitar | ||
| 100 Hz | –2–3 | Reduces muddiness |
| 150–250 Hz | +2 | Adds warmth |
| 2.5–4 kHz | +2–3 | Adds attack or punch |
| 5 kHz | +2–3 | Adds bite |
| Acoustic guitar | ||
| 80 Hz | –3 | Reduces muddiness |
| 150–250 Hz | +2–3 | Adds warmth |
| 800–1000 Hz | –2–3 | Reduces boxiness |
| 3–5 kHz | +2–3 | Adds attack or punch |
| 7 kHz | +2–3 | Adds brightness |
| Bass guitar | ||
| 100–200 Hz | +1–2 | Adds fullness |
| 200–300 Hz | –3–4 | Reduces muddiness |
| 500–1000 Hz | +2–3 | Adds punch |
| 2.5–5 kHz | +2–3 | Adds attack |
| Kick drum | ||
| 80–100 Hz | +1–2 | Adds body or depth |
| 400–600 Hz | –3–4 | Reduces boxiness |
| 2.5–5 kHz | +1–2 | Adds attack |
| Snare drum | ||
| 100–150 Hz | +1–2 | Adds warmth |
| 250 Hz | +1–2 | Adds depth or body |
| 800–1000 Hz | –2–3 | Reduces boxiness |
| 3–5 kHz | +1–3 | Adds attack |
| 8–10 kHz | +1–3 | Adds crispness |
| Tom-toms | ||
| 200–250 Hz | +1–2 | Adds depth |
| 600–1000 Hz | –2–3 | Reduces boxiness |
| 3–5 kHz | +1–2 | Adds attack |
| 5–8 kHz | +1–2 | Adds presence |
| Large tom-toms | ||
| 40–125 Hz | +1–2 | Adds richness |
| 400–800 Hz | –2–3 | Reduces boxiness |
| 2.5–5 kHz | +2–3 | Adds punch or attack |
| Hit-hat | ||
| 10+ kHz | +3–4 | Adds brightness or sheen |
| Cymbals | ||
| 150–200 Hz | –1–2 | Reduces rumbling |
| 1–2 kHz | –3–4 | Reduces trashiness |
| 10+ kHz | +3–4 | Adds brightness or sheen |
| Drum overheads | ||
| 100–200 Hz | –2–3 | Reduces muddiness |
| 400–1000 Hz | –2–3 | Reduces boxiness |
| High percussion | ||
| 500– Hz | –6–12 | Cuts boxiness |
| 10+ kHz | +3–4 | Adds brightness or sheen |
| Low percussion | ||
| 250Hz and below | –3–4 | Reduces muddiness |
| 2.5–5 kHz | +2–3 | Adds attack |
| 8–10 kHz | +2–3 | Adds brightness |
| Piano | ||
| 80–150 Hz | +2–3 | Adds warmth |
| 200–400 Hz | –2–3 | Reduces muddiness |
| 2.5–5 kHz | +2–3 | Adds punch or attack |
| Horns | ||
| 100–200 Hz | +1–2 | Adds warmth |
| 200–800 Hz | –2–3 | Reduces muddiness |
| 2.5–5 kHz | +2–3 | Adds punch or attack |
| 7–9 kHz | +1–2 | Adds breath |