Before you reach for an EQ band, know what lives there. The chart lays the instruments' open strings and the voice types out on the 20 Hz – 20 kHz scale your EQ uses, with the standard band centres and the note every frequency belongs to.
| ISO 266 band centre | Nearest note | Cent |
|---|
Red dots are the open strings in standard tuning — guitar E A D G B E, bass E A D G (and the low B of a five-string), violin G D A E, viola and cello C G D A, ukulele G C E A — and the bar is the 88-key piano from A0 (27.5 Hz) to C8 (4186 Hz). The voice bars are the voice-type ranges used by the Vocal Range Test, after McKinney (1994) and Boldrey (1994). Every position is computed from equal temperament with A4 = 440 Hz.
These are fundamentals. Every instrument also has overtones far above its lowest note — that is what a high-shelf or a presence boost works on — and how strong they are depends on the instrument and the player, so the chart does not draw them.
Graphic EQs and analysers label their bands with the preferred frequencies of ISO 266: 31.5, 63, 125, 250, 500 Hz, 1, 2, 4, 8 and 16 kHz for octaves, and the values between for third-octaves. They are rounded from exact centres 10n/10 × 1 kHz, which is why 63 Hz is not exactly half of 125 Hz. The table gives the note each centre is closest to.
Why is the axis logarithmic?
Because hearing is: every octave doubles the frequency, so 20–40 Hz and 10–20 kHz are each
one octave and get the same width — the way an EQ and your ear treat them.
Where is the kick drum?
A drum has no single note, so it has no dot. Tune your kick or 808 with the
808 Key Finder, which reads its actual
pitch.
Can I hear a frequency?
Click anywhere on the chart or on a dot: a sine tone plays at that frequency. For a steady
tone or a sweep, use the
Tone Generator.