SpectroTyper – Hide Text in a Spectrogram With Sound
Text in soundReady
- Start quiet, raise slowly
- Check L/R markings first
- Disable audio enhancements
- Runs inside your browser
- No upload, no account
- Nothing saved after you close
Turn text into a spectrogram message
SpectroTyper converts letters into tones whose pattern spells your message when viewed as a spectrogram.
How SpectroTyper works
Each column of a 5×7 letter bitmap becomes a short chord: every lit pixel adds a sine at its own frequency between 2 and 8 kHz.
Tips for clear text
Use short words, moderate volume and a quiet room.
Fun uses
Musicians have hidden images in tracks this way.
How to Use the
SpectroTyper
- 01
Type
enter up to 16 letters or digits.
- 02
Open
start the spectrogram on another device or tab with its mic near your speaker.
- 03
Play
press Play message.
- 04
Read
watch your text scroll across the spectrogram.
How SpectroTyper works
Each column of a 5×7 letter bitmap becomes a short chord: every lit pixel adds a sine at its own frequency between 2 and 8 kHz. Played in sequence, the chords paint the letters across time.
Tips for clear text
Use short words, moderate volume and a quiet room. A spectrogram with a high resolution shows sharper letters.
Fun uses
Musicians have hidden images in tracks this way. It is also a handy way to show students how spectrograms work.
Generators
Other generators
The signal generator and test-file generator create tones and files.
Related guides and fixes
Learn more in these guides: No sound on Windows, No sound on Mac, Headphones only one side, Speakers crackling, How to test speakers, How to test headphones.
Frequently Asked Questions
Q.Which characters work?
A–Z, 0–9 and space.
Q.Why is the text blurry?
Room echo and low analyser resolution; move the mic closer.
Q.Can I save it?
Record it with the voice recorder.