Tone Generator: Frequency Hz

Tone Generator is a precise frequency and sound generator for your phone. It plays test and reference signals: a single tone (sine wave, square, triangle or saw), a frequency sweep, white, pink or brown noise, beats, separate left and right channels, and up to four tones at once. Every sound is generated live on the device, from 20 to 20,000 Hz with an accuracy of 0.01 Hz.

What it is for
- Testing speakers and headphones: left and right channel, speaker phase (polarity), low and high frequencies, rattles and room resonances.
- Tuning and pitch: notes and cents, A4 at 432 or 440 Hz, and the pitch of your own voice.
- Acoustics and sound experiments: period and wavelength, overtones, beats, a live spectrum and test signals saved as WAV files.

Free modes
- Tone: type the frequency, use the slider, or step with minus and plus (0.01, 0.1, 1, 10 or 100 Hz; hold to change faster). Waveforms: sine, square, triangle and saw. The app shows the nearest note and its deviation in cents, with A4 at 432 or 440 Hz, plus the period and the wavelength in air.
- Your tone: hum or sing one steady sound for a few seconds. The app measures its frequency and can set it as the tone or as a base frequency in other modes.
- Reference frequencies: A4 440 and 432 Hz, a 1 kHz tone, 50 and 60 Hz mains frequency, and octave band centres from 31.5 Hz to 16 kHz.
- Sweep: the tone glides from a start to an end frequency in 5 seconds to 5 minutes, on a logarithmic or linear scale, up, down or up and down, once or repeated. Hold this frequency switches to Tone mode at the frequency playing right now, which helps you find the point at which something resonates or rattles.
- Noise: white, pink or brown, alone or mixed with the tone.
- Oscilloscope: the waveform of the output, live.
- Favorites: save up to 5 tones (frequency and waveform).
- Timer: 5 to 60 minutes with a gentle fade-out at the end.
- Playback continues with the phone locked, and the notification has a Stop button.

Plus edition
- Beats: binaural (a different tone in each ear, headphones needed) or isochronic (one tone switched on and off at a steady rate), with a difference from 0.5 to 40 Hz. The EEG band name of the difference is shown for reference, and the app tells you when no headphones are connected.
- L/R channels: a separate frequency, waveform and level in the left and right channel, or one channel only, for example to check headphones and speakers.
- Speaker phase test: the same tone in both channels, in phase or with the right channel inverted, to check whether two speakers are wired with the same polarity.
- Layers: up to four tones at once, each with its own waveform and level.
- Overtones: multiples of one base tone with adjustable levels and ready presets.
- Spectrum: a live frequency spectrum of the output with the strongest component in Hz and dB.
- Export to WAV: save the sound of any mode as a 48 kHz, 16-bit stereo WAV file (10 s to 5 min) in a place you choose.
- Up to 50 favorites.

The free modes work without limits. The Plus edition features come with three free sessions, so you can try them before buying. The Plus edition is a one-time in-app purchase, with no subscription.

Privacy
The app has no internet permission, no account, no ads and no analytics. The microphone is used only while you measure your tone; the sound is analyzed in your phone's memory and is never saved or sent. Settings stay on your device.

Listen safely
Start at a low volume and raise it slowly, especially with headphones and at high frequencies. Phone speakers and headphones do not reproduce the whole range evenly, so the lowest and highest frequencies may sound quiet or be inaudible.

The app is available in English and Polish, with a dark and a light appearance. Help inside the app explains every mode.

Contact: kontakt@itsound.pl

Recent changes:
Maintenance update: a newer version of one of the Android libraries the app is built with. Features, sound and privacy are unchanged.