40 Hz tone
The low E of a bass guitar, roughly.
Volume first. Turn your device volume down before pressing play, then raise it slowly. Tones start quiet on purpose. Very low tones can damage small speakers and woofers if pushed hard. Stop if you hear rattling, distortion or cone slap.
What 40 Hz is used for
The open low E on a four-string bass is about 41.2 Hz. Use it to check whether your system reaches the lowest note of most popular music.
| Period | 25.000 ms |
|---|---|
| Wavelength in air (20 °C) | 8.57 m |
| One octave down / up | 20 Hz / 80 Hz |
The generator above starts at 40 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 40 Hz tone?
Small speakers physically cannot move enough air at 40 Hz. Phones, laptops and most earbuds produce little or nothing this low; you need full-range speakers, good headphones or a subwoofer.
How long is one cycle of 40 Hz?
25.000 milliseconds. In room-temperature air the wavelength is about 8.57 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.
- Subwoofer testBass tones from 10 Hz, a low sweep and a room-mode calculator.