256 Hz tone
Scientific middle C.
Volume first. Turn your device volume down before pressing play, then raise it slowly. Tones start quiet on purpose. Keep headphones off your ears until you know how loud it is.
Hz
Logarithmic slider, 1 Hz to 22 kHz. Space bar starts and stops.Waveform
0 dBFS is the loudest your device can play; every 20 dB lower is a tenth of the amplitude.
What 256 Hz is used for
The "scientific pitch" C, set by powers of two. Standard concert middle C (C4) at A440 tuning is slightly higher, about 261.6 Hz.
| Period | 3.906 ms |
|---|---|
| Wavelength in air (20 °C) | 1.34 m |
| One octave down / up | 128 Hz / 512 Hz |
The generator above starts at 256 Hz. You can still move the slider to any other frequency, or open the full tone generator.
Questions people ask
Why can't I hear the 256 Hz tone?
Check the tab is not muted and the correct output device is selected. 256 Hz is well within the range of nearly every speaker and headphone.
How long is one cycle of 256 Hz?
3.906 milliseconds. In room-temperature air the wavelength is about 1.34 metres.
Keep testing
- Tone generatorSine, square, triangle and sawtooth from 1 Hz to 22 kHz.
- Frequency sweepLogarithmic or linear sweeps over any range and duration.
- Speaker testChannel, range and polarity checks for stereo speakers.