Test tones for speaker work.
Sine, square and sawtooth from 1 Hz to 22 kHz. Sweeps for finding rattles and coil rub, presets for the frequencies you keep coming back to, and a two-tone Pro mode. No account, no connection needed, so it works in a garage or a driveway with no signal.
Free. Pro Mode is a one-time purchase, not a subscription.
01Specifications
| Frequency range | 1 Hz – 22 kHz, min/max limits user-adjustable |
|---|---|
| Audio output | 44.1 kHz, 16-bit PCM |
| Waveforms | Sine, square, sawtooth |
| Frequency control | Slider with logarithmic, exponential or linear response; fine −/+ steps |
| Full-range sweep | 20 Hz – 20 kHz over 30 s (default) |
| Bass sweep | 30 – 100 Hz over 10 s (default) |
| Presets | 40, 50, 60, 70, 80, 220, 440, 1k, 10k Hz built in; up to 15 of your own |
| Display | Live waveform trace |
| Second tonePRO | Independent frequency, waveform and level |
| PulsePRO | Rate up to 20 Hz, duty cycle 10 – 90 % |
| Phase invertPRO | Per signal |
| Musical notesPRO | Chromatic, C to B, octaves 1 – 8 |
| RecordingPRO | Save tones as WAV files |
| Network | Not required |
| Platforms | Android 7.0 and later; iPhone |
02Bench notes
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After a refoam
Run the bass sweep at a modest level with the driver face up on the bench. Rub from an off-center coil, or a surround glued slightly crooked, shows up as a scratchy edge riding on the tone. When you hear it, stop the sweep and park on that frequency with the slider or the −/+ buttons.
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Chasing rattles
Door cards, license plates, trim panels, the sub box itself. Sweep 30 – 100 Hz with the system turned up, note where the buzz starts, then hold that frequency and press on panels until it stops.
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Checking each driver
Walk a sine from 50 Hz up past 10 kHz at low volume and listen near each driver in turn. A dead tweeter goes quiet at the top; a damaged woofer usually sounds rough or distorted at the bottom, well before it should.
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Two signals at once PRO
Two tones a few hertz apart beat audibly, which makes small differences easy to hear. Set both to the same frequency and invert one, and they cancel. Pulse mode gives you a repeating tone burst instead of a steady signal.
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Taking a signal with you PRO
Record a tone to a WAV file and play it from anything with a USB port or an aux input: a head unit, a DAW, the mixer at a gig.
Turn it down first. A steady tone puts continuous power into a voice coil in a way music never does, and tweeters are the first to cook. Square and sawtooth waves carry strong harmonics well above the fundamental: a 2 kHz square wave also puts real energy into the tweeter at 6 and 10 kHz.
A phone's own speaker gives out below a few hundred hertz, so a 40 Hz tone through it sounds like nothing. Use a cable into the system you're testing, or Bluetooth if that's what you've got.
03Screens
04Free & Pro
Everything you need to test a speaker is free. Pro adds a second signal and the tools that go with it, and it's a single purchase inside the app.
| Feature | FREE | PRO |
|---|---|---|
| Single tone, 1 Hz – 22 kHz | yes | yes |
| Sine, square, sawtooth | yes | yes |
| Full-range and bass sweeps | yes | yes |
| Built-in and custom presets | yes | yes |
| Log, exponential or linear slider | yes | yes |
| Live waveform display | yes | yes |
| Second independent tone | — | yes |
| Pulsed tones, rate and duty cycle | — | yes |
| Phase invert | — | yes |
| Musical notes by octave | — | yes |
| Record to WAV | — | yes |