9000 Hz
Treble (4–20 kHz) · C#9
Turn the volume down before you play. A pure tone is harder on the ears than music at the same level.
Common value
A value that comes up often in searches and tests.
| Wavelength | 3.8 cm |
|---|---|
| Period | 111.1 µs |
| Nearest note | C#9 |
| Off by | +25 cents |
| Audible | Yes |
| Harmonics | 18000 Hz · 27000 Hz · 36000 Hz |
| One octave down | 4500 Hz |
| One octave up | 18000 Hz |
How to read this
- Hertz counts how many times the air vibrates per second. The bigger the number, the higher the pitch.
- Wavelength is the speed of sound (343 m/s at 20 °C) divided by the frequency. That makes 20 Hz seventeen metres long and 20 kHz under two centimetres.
- People hear roughly 20 Hz to 20 kHz, but the upper limit drops with age. Past about 15 kHz, some hear the tone and some do not.
- Hearing nothing does not mean the equipment is broken. Small speakers cannot reach the low notes, and for the high ones it is the ear that gives up first.
Frequently asked questions
Q. What does 9000 Hz sound like?
It is a pure tone vibrating 9000 times a second. It falls inside the range people hear, and the nearest musical note is C#9.
Q. What is the wavelength of 9000 Hz?
3.8 cm in air. Sound travels 343 metres per second through 20 °C air, so the wavelength is that distance divided by 9000.
Q. What note is 9000 Hz?
The nearest note is C#9, and it is 25 cents sharp. A semitone is 100 cents, so that is about 25% of a semitone away.
Q. I cannot hear 9000 Hz — is something wrong?
This band is comfortable for most equipment and most ears, so check the volume and the output device first.
Q. What are the harmonics of 9000 Hz?
The whole-number multiples: 18000 Hz, 27000 Hz, 36000 Hz. An octave up is double, 18000 Hz; an octave down is half, 4500 Hz.
Nearby frequencies
Frequency doubles for every octave, so closeness is measured in ratios, not differences.