Start with your device volume low. Very low tones may be inaudible on phone or laptop speakers; very high tones can be uncomfortable on headphones.
Frequency sweep
How to use the tone generator
Press Play, then drag the slider or use ×2 / ÷2 to jump an octave and ±1 to fine-tune. Change the waveform to hear how harmonics alter the timbre: a sine wave is pure, a square wave contains odd harmonics, a sawtooth contains all of them.
The sweep plays a smooth exponential glide between two frequencies – useful for finding room resonances, testing speakers and headphones, or checking the limits of your hearing.
What it is useful for
Tuning instruments, checking speakers and subwoofers, locating rattles in a car or room, demonstrating beats and interference in class, masking tinnitus (ask your audiologist first), and simply hearing what a frequency sounds like.
Frequently asked questions
Is the tone generator safe for my ears and speakers?
Start at low volume. High frequencies and square waves sound much louder than you expect, and very low frequencies at high level can damage small speakers.
Why can't I hear very low or very high tones?
Most phone and laptop speakers cannot reproduce frequencies below about 150–300 Hz, and hearing above 15–17 kHz declines with age.