Tone generator
Any frequency, any wave, left or right.
Presets
Nothing leaves your device
This tool runs entirely in your browser. What you type, play or record here stays on your device: nothing is uploaded or saved on a server.
Example
Example: a 10-second sweep to find where a speaker rattles
Sweep starts at 20 Hz and glides to 20,000 Hz in 10 seconds. The glide is logarithmic: the frequency doubles about every second, so each octave gets the same time. Turn the volume down before pressing Play.
- A rattle that starts about 4 seconds in is near 317 Hz.
- Switch to Tone, type 317 and nudge it with −1 and +1 until the rattle is loudest; ÷2 and ×2 jump an octave, to 158.5 or 634 Hz.
- Set Channel to Left, then Right, to hear which speaker it comes from.
| After | Frequency |
|---|---|
| 0 s | 20 Hz |
| 1 s | ≈ 40 Hz |
| 2 s | ≈ 80 Hz |
| 3 s | ≈ 159 Hz |
| 4 s | ≈ 317 Hz |
| 5 s | ≈ 633 Hz |
| 6 s | ≈ 1,262 Hz |
| 7 s | ≈ 2,518 Hz |
| 8 s | ≈ 5,024 Hz |
| 9 s | ≈ 10,024 Hz |
| 10 s | 20,000 Hz |
The rattle now sits on one frequency you can hold for as long as it takes to find the loose part. The same sweep on headphones shows where their bass fades and where the top end stops.
How it works
- Turn the volume down first, then type a frequency or use the slider, the ×2 and ÷2 octave buttons or a preset (440 Hz is the A4 tuning note).
- Choose the wave and the channel — left or right alone makes a quick speaker or headphone test.
- Or sweep a range to find rattles and resonances, or run the hearing test to see the highest pitch you hear.
Frequently asked questions
- What can a tone generator be used for?
- Checking speakers and headphones (left and right, bass response, rattles), tuning to a reference pitch, science lessons on sound, finding the frequency of a hum, and tinnitus pitch-matching to describe it to a doctor.
- Why can’t I hear the lowest or highest tones?
- Small speakers can’t reproduce much below 100–200 Hz or above about 15–16 kHz, and human hearing tops out between about 12 and 20 kHz depending on age. Try headphones.
- Is it safe?
- Keep the volume low: pure tones, especially high ones, can be louder than they seem and are tiring to listen to. Stop if they are uncomfortable.
- What does the sweep do?
- It glides from one frequency to another over the time you choose, on a logarithmic scale so each octave takes the same time — useful to hear where a speaker buzzes or a room booms.
- How does the hearing test work?
- It plays three short beeps at 20 kHz, then at 19, 18, 17, 16, 15, 14.1, 12, 10 and 8 kHz, and stops at the first you hear. That is your highest pitch heard, shown beside a rough age guide: 15 kHz, for instance, is typical under 40. It is not a medical hearing test.
- How do I test left and right speakers?
- Choose Channel: Left and press Play; the tone should come only from the left speaker or earpiece. Then choose Right. Both plays it on both. A sine at 440 or 1,000 Hz is easy to place.
- Is anything recorded?
- No. The tones are made in your browser; nothing is recorded or sent anywhere.