DTMF Tones

DTMF Tones produces the touch-tone sounds a telephone keypad sends when you dial: each character is a pair of tones played together, separated from the next by a gap of silence. It is used for telephony testing and for sound design when a scene needs a dialling sequence.

Where to find it

Generate → DTMF Tones.

Controls

• DTMF sequence — the characters to generate. Numbers 0 to 9, lower case letters a to z, and the * and # characters are accepted, one tone per character. The default sequence is audacity.
• Amplitude (0-1) — the level, where 1 is full scale. Default 0.8.
• Duration — the total length of the whole sequence, tones and gaps together, entered as a timecode.
• Tone/silence ratio — a knob, with a numeric field beside it, splitting that total between sound and silence. Range 0 to 100, default 55.

Beside the knob the dialog reports the figures it works out from your settings: Duty cycle as a percentage, and Tone duration and Silence duration in milliseconds.

Notes

Duration is the length of the entire sequence, not of one tone. Adding characters to the sequence therefore makes each individual tone shorter unless you lengthen the duration to match.

A ratio of 100 gives continuous tones with no gaps between them, and 0 gives silence throughout. The default of 55 leaves a little more tone than gap, which is roughly what a real keypad produces.

Generation starts at the beginning of the selection, or at the cursor if nothing is selected. The duration has to be greater than zero before the effect can be applied.

Last updated 3 September 2026