Create standard test signals for your audio circuits
This signal uses a predefined set of frequencies (300Hz to 3150Hz) as specified by the ITU-T P.501 standard for telephony bands.
Generates white noise, with equal power spectral density across the entire frequency band.
Generates pink noise, with a power spectral density that decreases by 3dB per octave. It sounds more natural to the human ear.
Duration is determined by the text for TTS.
A 1 kHz sine wave is the universal line-up tone, but the level it should sit at depends on where in the world you are working:
Send a 1 kHz tone at the correct level down the line, ask the far end what they are reading, and any discrepancy is a gain error you can measure instead of argue about. Thirty seconds of tone at the head of a tape or a file has resolved more disputes than any amount of listening.
A sweep will tell you whether both sides are working across the whole range and whether anything is loose. A steady sine at a low frequency reveals distortion that music hides. Start quiet: a full-scale tone into headphones is unpleasant and can be harmful.
The same tones let you verify a whole path: generator, console, converter, distribution, monitor. Inject a known level at one end, measure at the other, and the difference is the answer. It is the simplest diagnostic in audio, and the one most often skipped.
In a broadcast plant the same logic applies to timing rather than level: you inject a known reference and check that every device agrees with it. That is the part we build hardware for.
These tools are free because we build the equipment that does the same job in a control room, twenty-four hours a day, without a browser tab open.
Elettronica Mangione has been designing broadcast synchronisation systems in Rome since 1984, with over 1,000 installations in 15 countries. Talk to a timing engineer.
White noise has equal energy per hertz and sounds bright. Pink noise has equal energy per octave, which matches how human hearing is organised, and sounds balanced. Pink noise is the correct choice for setting up loudspeakers and measuring rooms; white noise is used for electrical measurements.
−18 dBFS in Europe, following EBU R68, and −20 dBFS in North America, following SMPTE practice. The difference is the amount of headroom left above the alignment level.
It sits in the middle of the audible range, it is easy for meters and ears to read, and it is unaffected by the low- and high-frequency roll-off at the edges of most equipment.
Yes. A slow sweep from 20 Hz to 20 kHz reveals rattles, resonances and dropouts at the exact frequency where they occur, which points you at the cause. Start at a moderate level.
Only at low level. A full-scale sine wave is far louder than it sounds at first and can damage hearing and drivers. Start quiet and raise the level gradually.
Yes, with no registration. All signals are synthesised in your browser.