Studio utilities / Signal reference
Audio Test Signals
Reference tones, frequency sweeps and playback-system checks.
All studio resources →Third-octave reference signals
Playback level: Begin at a low volume. The lowest and highest bands may be inaudible on your system; do not increase gain to compensate.
Choose sine tones at the nominal center frequencies or pink noise confined to each third-octave band. Downloads are 30-second mono 48 kHz / 16-bit WAVs at −18 dBFS peak, with 100 ms fades. These are general-purpose references, not certified filter-test signals.
Low / 12.5–200 Hz
Mid / 250 Hz–2 kHz
High / 2.5–20 kHz
Noise uses exact base-10 band edges; sine tones use the displayed nominal frequency. All files share peak level, not equal RMS or perceived loudness. Phone speakers will not reproduce the lowest bands; do not turn up the volume to compensate.
Logarithmic frequency sweeps
20 Hz–20 kHz
Full-range sweep for recording and playback systems. Equal time per octave; 30 seconds, −18 dBFS peak.
20–200 Hz
Bass sweep for subwoofer integration and low-frequency checks. Equal time per octave; 30 seconds, −18 dBFS peak.
Downloadable reference signals for basic acoustical checks, system testing, demonstrations, and troubleshooting. Noise and tone files are generated as 30-second mono 48 kHz / 16-bit WAV files; the full-scale impulse file is 10 seconds. No registration is required.
Level caution: Start playback at a low volume. Pure tones and broadband noise can become uncomfortable or damaging at high playback levels.
Broadband Noise
White Noise
Equal energy per hertz; useful for broad-spectrum testing.
Pink Noise
Approximately equal energy per octave; commonly used for audio and room testing.
Brown Noise
Stronger low-frequency emphasis than pink noise.
Concert A tuning reference
440 Hz — A4
Standard tuning reference. For other frequencies, use the third-octave bank above.
Channel Identification Tracks
Stereo 2.0 — Left / Right
Two-channel WAV with a short 1 kHz identification tone first in the left channel, then in the right channel.
5.1 Surround Channel Identification
Sequential 1 kHz tone bursts: Front Left, Front Right, Center, LFE, Surround Left, Surround Right.
7.1 Surround Channel Identification
Sequential 1 kHz tone bursts: Front Left, Front Right, Center, LFE, Back Left, Back Right, Side Left, Side Right.
Impulse / Reverberation Test Signal
Full-Scale Digital Impulse — 0 dBFS Peak
A single-sample full-scale impulse followed by silence, intended for room/system impulse-response and reverberation-decay checks when reproduced through a suitable loudspeaker system.
Use caution: begin with playback gain very low. A full-scale impulse has extremely high crest factor and can stress loudspeakers or produce unsafe acoustic levels if reproduced carelessly.
About These Files
These signals are provided as convenient general-purpose references. They are not a substitute for a calibrated acoustic source, calibrated instrumentation, or the signal requirements of a specific ASTM, ANSI, ISO, IEC, OSHA, or project test procedure.