Frequency sweep generator
Sweep a tone across any range, smoothly or in steps, to find where speakers start and stop, what rattles and where your room booms. Play it here or download it as a WAV file.
Volume first. Turn your device volume down before pressing play, then raise it slowly. Tones start quiet on purpose. High-frequency tones can seem silent and then turn painfully loud when volume goes up. Never raise the volume just because you hear nothing.
The WAV is rendered on your device at 48 kHz, 16-bit stereo, using the settings above, so you can play it from a USB stick, a TV or measurement software.
How to read a sweep by ear
- Where it starts: the first moment you hear a pitch is roughly your speaker's low-frequency limit at that volume.
- Swells and dips: loudness that jumps up and down in the bass is the room, not the speaker. Move your head half a metre and it changes.
- Buzzes: a buzz that appears only at one pitch is a resonance, often a loose panel or object nearby.
- Where it ends: the top end fades with the speaker, the connection (Bluetooth may stop at 16–20 kHz) and your own hearing.
The logarithmic setting doubles the frequency at an even rate, so a 20 Hz to 20 kHz sweep spends the same time on each of its ten octaves.
Ready-made sweeps
- 20 Hz to 20 kHz sine sweep: The classic full-range test: one smooth logarithmic glide across the whole textbook range of human hearing.
- Bass sweep, 20 Hz to 200 Hz: A slow sweep through the subwoofer and bass range, where rooms and enclosures cause the most trouble.
- High frequency sweep, 1 kHz to 20 kHz: A treble-only sweep for tweeters, earbuds and the upper limit of your hearing. Keep the volume low.
- Descending sine sweep, 20 kHz to 20 Hz: The same full-range sweep played top to bottom.
Logarithmic vs linear, in numbers
| 20 Hz → 20 kHz in 20 s | Log sweep reaches | Linear sweep reaches |
|---|---|---|
| after 2 s | 40 Hz | 2,018 Hz |
| after 10 s | 632 Hz | 10,010 Hz |
| after 18 s | 10 kHz | 18,002 Hz |
A linear sweep is over the entire bass and midrange in its first two seconds. That is why log sweeps are the default for loudspeakers and rooms, while linear sweeps suit electronics work where bandwidth is measured in absolute hertz.
Measuring frequency response with a sweep
For a rough response check without special software, play the sweep on one device and run the spectrum analyzer with peak hold on another, placed at your listening position. The peak-hold line traces the response. For accurate curves you need a calibrated measurement microphone and software such as Room EQ Wizard, which can use the downloaded WAV.
What a frequency number actually means
Hertz counts how many times per second the air pressure swings back and forth. Drag the slider and watch 10 milliseconds of the wave: low notes fit only a few slow cycles, high notes cram in hundreds. Because sound travels at about 343 metres per second in room-temperature air, every frequency also has a physical size, its wavelength.
- Cycles in 10 ms
- 6.3
- One cycle lasts
- 1.58 ms
- Wavelength in air
- 54.3 cm
- Nearest note
- D♯5
A 632 Hz wave is about the length of a ruler. That is why bass fills a whole room and bends round corners while treble beams straight from a tweeter and is easily blocked.
Questions people ask
What is a frequency sweep?
A test signal whose frequency changes continuously (or in steps) from a start value to an end value over a set time. Played through a speaker or headphone, it reveals where output starts and stops, resonances that rattle or boom, and dips caused by the room.
What is a sine sweep (chirp)?
A frequency sweep made from a pure sine wave, so only one frequency plays at any instant. Engineers also call it a chirp. Logarithmic sine sweeps are the basis of the exponential swept-sine technique (Farina, 2000) used by measurement software to capture frequency response and distortion.
Smooth or stepped sweep?
A smooth sweep glides continuously and is best for finding the exact frequency of a rattle. A stepped sweep holds each frequency for a moment, which makes it easier to compare loudness from one step to the next or to read a level meter at each frequency.
Should I use a logarithmic or linear sweep?
Logarithmic for almost everything audio. It spends equal time on each octave, which matches how we hear pitch, so bass and treble get fair attention. A linear sweep races through the bass and spends most of its time above 10 kHz.
How long should a frequency sweep be?
10 to 30 seconds is plenty for listening tests. Longer sweeps make it easier to press Mark at exactly the right moment when you hear a rattle or a drop-out.
Can I use this sweep to measure frequency response?
For a rough picture, play the sweep on one device and watch it on the spectrum analyzer on another, with peak hold on. For accurate measurements you need a calibrated measurement mic and dedicated software such as Room EQ Wizard.
Keep testing
- Tone generatorSine, square, triangle and sawtooth from 1 Hz to 22 kHz.
- Subwoofer testBass tones from 10 Hz, a low sweep and a room-mode calculator.
- Spectrum analyzerReal-time FFT of your microphone with peak hold and note readout.