OneTaskBy Tim King · Updated
Sweep Generator
Sine Sweep Tone from 20 Hz to 20 kHz, Export as WAV
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How the Sweep Generator works
This sweep generator plays a sine tone that glides from one frequency to another, 20 Hz to 20 kHz by default, while the panel shows the frequency you are hearing. Set the start, end, duration and curve, press Play, and press Export to save the exact same sweep as a WAV file for a speaker check, room measurement or hearing test.
A sweep (also called a chirp) is a single sine wave whose frequency changes over time. It visits every frequency in the range once, which makes it the quickest way to hear how a system responds from the bottom of the range to the top.
Choosing a curve in the sweep generator
Logarithmic is the default and the one to use for audio. Each octave takes the same time, so a ten-second sweep from 20 Hz to 20 kHz — almost exactly ten octaves — spends about a second on each. That matches how we hear pitch, and it is the curve measurement software expects for an "exponential sine sweep".
Linear changes by the same number of hertz every second. From 20 Hz to 20 kHz it rushes through the bass in a fraction of a second and spends half its time above 10 kHz. It is useful when you want equal time per hertz, for example to test a narrow band or a filter, but it sounds lopsided over the full audio range.
What to listen for. On speakers, note where the bass first becomes audible and where the treble fades; rattles at one frequency point to a loose panel or a room resonance. On headphones, a sweep is a quick hearing check — most adults stop hearing somewhere between 14 and 17 kHz, so silence at the top is usually the ears, not the equipment.
Clicks and levels. The sweep fades in and out over 20 ms so it does not click at either end. The export is a 16-bit mono WAV at 48 kHz, which reaches up to 24 kHz, so a 20 kHz end point is rendered cleanly. The volume slider scales on a squared curve; a full-scale sine is louder than most music, so start low.
FAQ
Can I use the exported sweep for room measurement?
Yes for a rough listening check. For an impulse response, measurement tools such as REW generate their own sweep so they can deconvolve it exactly; use theirs when you need numbers.
Why do some parts of the sweep sound louder than others?
The signal level is constant; your speakers, room and ears are not. Human hearing is most sensitive around 2–5 kHz, and rooms boost some bass frequencies and cancel others, so an even sweep sounds uneven.
Can I sweep downwards?
Yes. Set the start frequency higher than the end frequency and the sweep falls instead of rising. A falling sweep is handy for checking that a tweeter and woofer hand over smoothly in both directions.
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