Headroom and max headroom in audio production
What is headroom / headroom?
Headroom in audio production is the level span between the largest peak of a level and the clipping limit. In the digital range we are talking about values up to 0 db (fs) and in the analog range of values up to 25 db (u). Important terms that play a role in headroom or max headroom include the noise flor and SNR (signal to noise ratio). Both in mixing and Headroom is an important factor in mastering.
Every recording medium or every analog device, be it microphone or converter in the interface, has a noise level. This level is also known as "analog noise". If a signal is recorded very quietly, the difference between the background noise and the recorded signal is rather small. This difference is called SNR (signal to noise ratio) mix down, just at subsequent compression cause problems, as the background noise is also compressed and thus the noise can be heard by the subsequent increase in the level.
Tip for admission:
If possible, level the signal between -6 and -3 db (fs). So you still have enough dynamic leeway for somewhat louder passages. In classical music or in very dynamic pieces, we recommend setting the audio signal between -12 and -6 db (fs).
Headroom when mixing is important because you can use your song as much as possible Bring mastering to a loudness that on the one hand corresponds to the current productions, but on the other hand loses as little of its own dynamism as possible. Here it makes sense to set a headromm of 3-6 db (fs) and accordingly to level the individual tracks in the mix so that this maximum headroom is achieved. So later in mastering you have fewer problems with instruments suddenly appearing much more than you originally thought in the mix. However, this cannot be completely avoided, since in mastering through the Limit strong compression takes place. This can only be avoided by sufficiently compressing the individual tracks in the mixdown so that a certain loudness is created for the desired headroom. However, there are no fixed guide values for this. It is up to the engineer to decide this.
Sufficient headroom is desirable and useful, especially when it comes to a sensitive topic such as mastering. Processors and devices that handle dynamics often have to be used in the mastering process. For example, to achieve a compression of the signal or to raise individual frequency bands to compensate for the under-emphasis.
It is best to leave between 3 and 5 db (fs) headroom for mastering. This gives the mastering engineer enough leeway to get the best out of your song.
3 db headroom or 6 db headroom - which is better?
First of all, we need to understand the following. For every 6 db that a song has less gain, we lose 1 bit of dynamics. In pop productions, this may be less important, but in productions that are fundamentally very dynamic, such as in classical music, it can be an essential feature. Even if we export a song with 24 bit, we have a dynamic range of 144 db in which we can let off steam. So if we mix a song with relatively high dynamics and bounce it with a headroom of 18 db (fs), we not only lose 3 bits (we only have 24 bits instead of 21), but also reduce the signal-to-noise ratio considerably a subsequent compression, which can lead to undesirable effects.
Conclusion: We recommend 6 db headroom for dynamic productions. For less dynamic productions 3 db headroom.
What does a 24 bit file or 32 bit (float) file have to do with headroom?
As already described above, with 24 bit we have 144 db dynamic range. With a 32 bit (float) file, however, we have unlimited dynamics. Well not unlimited. More like 1680 db. Which can be described as almost unlimited. With a 32 bit file, the headroom no longer plays a role, because on the one hand we no longer have digital clipping and on the other hand no more rounding errors can occur.
If possible, always export in 32 bit (float). Always set the internal Mixbus resolution in 32 bit (float) - if this is possible.