How to use the frequency sweep
- The sweep is set from 20 Hz to 20,000 Hz over 20 seconds. Turn the volume down first.
- Press Play and listen. The current frequency is shown as it rises.
- Note where the sound appears and where it disappears, and listen for rattles, buzzing or sudden peaks.
- Change the range and duration, for example 20–200 Hz for a subwoofer, and download the sweep as WAV for other players.
What a sweep reveals
A sine sweep plays every frequency in turn, so it shows how a system responds across the audible range. Small speakers usually become audible around 100–200 Hz, decent bookshelf speakers at 50–60 Hz and subwoofers lower still. Loud spots at particular low frequencies are often room modes, caused by the room's dimensions, rather than the speaker itself. Rattles show loose panels or furniture. At the top, the sweep disappears where either the speaker or your hearing ends, typically between 14 and 18 kHz for adults.
The sweep is logarithmic, spending equal time on each octave, which matches how we perceive pitch. It is generated in your browser with the Web Audio API.
FAQ
Why does the sweep start silently?
Very low frequencies are below what most speakers can play and are hard to hear.
Is a sweep safe for tweeters?
At moderate volume, yes. Avoid loud high-frequency tones.
Linear or logarithmic sweep?
Logarithmic, so each octave gets the same time.