What does headroom mean?

[Xpred]

When you guys say headroom, what do you mean exactly?

[sixways]

how much room a mastering engineer has to work with.

like if your mix is already at 0db, your mastering engineer doesn't have much wiggle room.

anyone else..am I right?

6

[Xpred]

Ah... could you just decrease the volume for that mix? Will it work?

[BrentDomann]

Headroom refers to the difference (in dB) between the nominal input level in an audio system and the maximum level before clipping (distortion) occurs.

In layman's terms, your system has particular electronic specs, and there is a certain sound amplitude level at the input (the front end) that the system most efficiently handles. That's the "nominal level". If the signal is too hot (i.e. it's turned up to high), it will overdrive the electronics and you will get distortion. Headroom is the difference (usually in decibels, or standardized measurements of amplitude) between the "special level that your system works best with" and the point at which distortion occurs.

The benefit of having high headroom is that if you have a really dynamic sound source (for example, if your sound goes from really quiet to really loud really quickly), you can run your quietest sounds closer to this "nominal level" without worrying about your loudest sounds overdriving your equipment and getting distorted. Obviously you don't want distortion, but you might be wondering, "Why wouldn't I just accept a system with low headroom and turn down my levels to avoid distortion?" The answer is that your system makes its own noise, and this noise comes through the outputs with your signal. The louder your signal is relative to this noise, the cleaner your output signal. Thus a system with high headroom can be run hotter on quiet sound sources--allowing for this cleaner signal--and ALSO be able to avoid distortion.

Another benefit is that, even though you should want to maintain your signal close to the nominal level at all times, you have more room to boost the signal in the system on the front end before distorting on the back end. That is, you will lose quality if you use your headroom as "room to amplify more", but at least you have that option of always getting a little louder. I guess you could say "it goes to 11".

[sixways]

decreasing your pre-mastered levels will give you more headroom..good rule of thumb is -6db.

again, anyone else..am I right here?

6

[Massive Master]

Brent pretty much nailed it. It isn't just something you leave for the mastering guy (although we certainly appreciate it). It's something you should take advantage of on every single track you record from start-to-finish.