What the noise colours are
The names describe slope across the spectrum. White is flat, pink falls at three decibels per octave, brown falls at six, and blue rises at three. That is the whole definition and it explains every practical use.
| Colour | Slope | Best used for |
|---|---|---|
| White | Flat | Impulse and resonance tests |
| Pink | -3 dB/oct | Full-range mixing reference |
| Brown | -6 dB/oct | Low-end and sub checks |
| Blue | +3 dB/oct | High-end and air |
Pink noise works well as a mixing reference because its decline matches how human hearing weights frequency, so it sounds evenly bright rather than hissy.
The noise floor of a mix
Every recording has a floor. Analogue chains have thermal noise, digital chains have quantisation noise, and cheap converters can add more of both. The floor is what remains when the music stops.
It only becomes a problem when it rises above the quietest moments you care about. That is a measurement, not an opinion, so find the number before deciding whether to do anything.
Using each colour in practice
- Pink noise through a monitor plays back evenly and reveals imbalance faster than most alternate methods.
- Brown noise checks whether your sub survives on systems with no bass response at all.
- Blue noise across the top end exposes sibilance and harshness that full-range noise hides.
- White noise through a resonant filter makes the peak easy to find and hear.
Reducing it without damage
If it is genuinely audible, the safest route is at the source: a better converter, a gain structure that is not pushing a noisy preamp, or simply recording the room quieter. Gate and multiband compression help on individual tracks. Heavy spectral repair on the master usually costs more in artefacts than it returns.
There is a measurement worth doing before anything else. Note the level in a genuinely silent passage with the faders up, then note the level during the quietest music you care about. If the two are close, the floor is not a problem and you have saved yourself a repair that would only degrade the material.
Where repair is warranted, treat it as a mix decision rather than a technical one. A short gate on a noisy reverb return often removes more audible noise than any master processing, because the noise is gone before it can be encoded and it costs nothing in quality.
The exception is archival work where the source is fixed. There, spectral repair earns its place, but work in passes and check the result at normal volume rather than by zooming in, because artefacts that look obvious under inspection are frequently inaudible in context and occasionally disguise the noise better than the noise did.
The bottom line
Noise is a tool with a spectrum, not a nuisance. White noise is flat, pink leans low, brown falls away steeply, and each does a specific job. The noise floor of a mix is a real measurement you can act on, and it is separate from the question of whether the music is loud enough.
Judge it in the right domain
432Hz MASTER shifts pitch only, so you can compare noise beds against your low end without the reference moving underneath.
Frequently asked questions
What is a noise floor?
It is the level of the signal present when the intended sound stops. In a quiet passage it becomes the floor of what the listener hears, and if it is high enough it becomes audible as a hiss.
Which noise colour is best for mixing?
Pink noise for broad checks because its energy follows the ear's own sensitivity curve, brown noise for low-end work, and blue or high-passed noise for testing the top end in isolation.
Does noise masking a mix matter?
Only if it is audible. A floor sitting below the music is harmless and often unavoidable in digital production. The problem begins when it crosses above the quietest parts you actually care about.
Should I remove noise before mastering?
Only if it is audible at playback level, and aggressive noise reduction usually costs more in artefacts than it returns. Measuring the floor first is more useful than assuming it needs removing.