Audio Tools

Questions and answers

What's the difference between white, pink and brown noise?

They differ in how their energy is spread across the frequency range. White noise has equal energy at every frequency, so it sounds bright and hissy, like a detuned radio. Pink noise falls away gently towards the treble and sounds softer, like steady rain. Brown noise falls away more steeply and sounds like a deep rumble or distant surf. Many people find pink or brown noise more comfortable for sleep, and white noise better for masking speech in an office. Each generator has a volume control and a sleep timer, and the Noise Mixer lets you blend all three.

Should I use the Pitch Shifter, the Voice Pitch Changer or the Speed Changer?

Use the Pitch Shifter to make something higher or lower while keeping its length the same, for example to move a backing track into your singing key. Use the Speed Changer to slow down or speed up without changing the pitch, which is ideal for learning a fast solo or listening to a lecture at 1.5×. The Voice Pitch Changer does both at once, like speeding up a tape, for a quick chipmunk or deep-voice effect.

How loud should my podcast or music be?

Streaming services measure loudness in LUFS and turn tracks up or down to a target: about −14 LUFS for Spotify and YouTube, and −16 LUFS for Apple Music and most podcast advice, while UK and European broadcasting uses −23 LUFS. Keep the true peak below −1 dBTP so the file doesn't distort when it's converted to MP3 or AAC. The LUFS Meter shows all of these figures and how each platform would treat your file.

What's the difference between the Spectrum Analyser and the Spectrogram Generator?

The Spectrum Analyser shows the frequency content live, as bars that move while the clip plays, which is good for watching what's happening right now. The Spectrogram Generator analyses the whole clip at once and draws a picture with time across and frequency up, with colour showing loudness. Use the spectrogram to find things over the whole recording, such as a steady mains hum line at 50 Hz, a squeak at a particular moment or where an MP3's high frequencies have been cut off.

Are my audio files uploaded anywhere?

No. Every tool reads and processes your audio in your browser using the Web Audio API, and the results are created on your device, so nothing is sent to a server. That also means very long files are limited by your device's memory: an hour of stereo audio takes around 1.3 GB once decoded, so for long recordings a laptop will cope better than an older phone. The microphone tools only listen while you allow them to, and you can stop them at any time.