A 1 kHz sine is the reference tone of audio engineering: levels, meters and line-up tones are specified at 1 kHz, and it is the usual pitch of a broadcast censor bleep. It sits where human hearing is sensitive, so it is easy to hear at a low level.
Which note 1,000 Hz is at other reference pitches
“In tune” depends on what A4 is tuned to, so the same frequency is a slightly different distance from the nearest note in each tuning.
| Reference | Nearest note | That note | 1,000 Hz is |
|---|---|---|---|
| A4 = 440 Hz · Standard (ISO 16) | B5 | 987.77 Hz | +21.3¢ |
| A4 = 432 Hz · “Verdi” pitch | C6 | 1027.5 Hz | −46.9¢ |
| A4 = 442 Hz · Orchestral | B5 | 992.26 Hz | +13.5¢ |
| A4 = 415 Hz · Baroque pitch | C6 | 987.04 Hz | +22.6¢ |
Octaves of 1,000 Hz
Doubling a frequency raises it an octave and halving lowers it one, so these all have the same note name and the same offset from it.
Harmonics of 1,000 Hz
A real instrument playing 1,000 Hz also sounds whole-number multiples of it. The first eight, and the notes they fall nearest:
| Harmonic | Frequency | Nearest note | Off by |
|---|---|---|---|
| 1 | 1000.0 Hz | B5 | +21.3¢ |
| 2 | 2000.0 Hz | B6 | +21.3¢ |
| 3 | 3000.0 Hz | F♯7 | +23.3¢ |
| 4 | 4000.0 Hz | B7 | +21.3¢ |
| 5 | 5000.0 Hz | E♭8 | +7.6¢ |
| 6 | 6000.0 Hz | F♯8 | +23.3¢ |
| 7 | 7000.0 Hz | A8 | −9.9¢ |
| 8 | 8000.0 Hz | B8 | +21.3¢ |
Period and wavelength
One cycle of 1,000 Hz lasts 1.000 milliseconds; in air at 20 °C, where sound travels at about 343 metres a second, one wavelength is 34.3 centimetres.