Free tool
Noise generator
Pink, white, brown, grey, green and speech masking noise for tuning, ringing out, checking a system and covering conversation, plus ambience beds like city traffic, an airport and an office. Runs in your browser, or download a WAV to play from anything.
Output
Stereo
Invert polarity
Turn your amp or speakers down before pressing Play. It starts at -30 dBFS.
Real-time analyzer
Play pink noise through the system and point your device's microphone at the speakers. The bars show how much energy is in each band, so a flat system shows flat bars. Nothing is recorded or sent anywhere.
View
Bands
Response
Input level–dBFS
Spread 100 Hz–10 kHz–dB
Loudest band–
Press Start RTA and allow microphone access. Phone and laptop mics roll off the deep lows and the top end, so treat those bands as rough. For a spectrum view and more options, open the full RTA analyzer.
Which one to use
- Pink sounds even across the range, so it is what an RTA or tuning app expects. Use it for setting EQ and checking that speakers sound balanced.
- White has much more energy in the highs. Use it to check tweeters and HF horns, at a low level.
- Masking follows the shape used by office sound masking systems: full below 250 Hz, then falling about 4 dB per octave, with the very lows and highs rolled off. It hides speech in the next seat or room without sounding like hiss. Play it quietly through ceiling or distributed speakers; in an open office it usually sits around 45 dBA at the listener.
- Grey follows the inverse of the ear’s equal-loudness curve at a quiet listening level, so lows and the very top get a boost and the 3 to 4 kHz region is pulled down. It is useful for judging what a system sounds like rather than what it measures, and for tinnitus masking. The boost is capped at about 18 dB so it won’t overdrive subs.
- Green is centered on about 500 Hz and falls away above and below. It is a soft background bed for lobbies and quiet rooms, and a quick check of the midrange.
- Brown is mostly low end. Use it to check subs, crossovers and rattles in the room.
- Ambience beds are built in your browser from noise, tones and a few short recordings, and loop every 48 seconds. They are always stereo. Use them as background for rehearsals, demos, testing intelligibility against real-world noise, or a quick room fill. City traffic, Airport, Metro station, Lobby, Office, Press cameras, Audience and Counting money are busy scenes; Cinema effects runs through sub, panning and impact effects to check a cinema or theater system, and is set by its peaks rather than its average with voices and events; Fan is steady.
- Use Left and Right to confirm wiring and polarity one side at a time. Uncorrelated sends different noise to each side, which is what some measurement tools want.
- Invert polarity flips the signal upside down on one side or both. With Mono noise and one side inverted, a correctly wired pair of speakers sounds thin, hollow and hard to place, and the bass drops away; if Off sounds like that instead, one speaker is wired backwards. Invert both to check the absolute polarity of a system against a reference.
- The real-time analyzer uses whatever microphone your device has. It isn't calibrated, so read the shape rather than the numbers: with pink noise playing, bands that stick up are where the system or room is heavy, and dips are where it is thin. Slow or Average steadies the bars so they are easier to read, and Average keeps adding up until you press Reset peaks. The thin marks above the bars are the peaks held since you last reset them. Spread is the gap between the highest and lowest band from 100 Hz to 10 kHz; under about 6 dB is a well-balanced system. Spectrum draws a continuous line smoothed to 1/12 octave, scaled like the bars so pink noise reads flat, for finding the exact frequency of a peak or dip. Spectrogram scrolls from right to left with low frequencies at the bottom and color for level, from dark blue to red; it shows tones that come and go, rings that hang on, and hum. All shows the bars, the spectrum line and the spectrogram together.
- Level is the average (RMS) level of the file. Peaks run up to about 15 dB higher, so the slider stops at -15 dBFS to avoid clipping. Turn up the amp or mixer for more.