DigitalMusicProduction wrote:So if the rule of peakIng up to -6dBFS is to leave headroom for Mastering, In my case seeing as its a straight solo piano recording with no intended effects or Mastering to be applied, i could just as well increase the gain and peak up to 3dBFS ?
It is a little confusing, and you mainly have to go slow and to resist the temptation to jump to conclusions before having understood it all
A mastering engineer may apply a little EQ, make parts of the track mono, look at the stereo width, etc... some this stuff will change the level of some of the frequencies in your mix, possibly increase it a little bit (in the sense that it has some peaks end up higher up in the full scale than before). It can also decrease it (if for example the mastering engineer see fit to make only cuts) or leave it unchanged (if the mix is perfect as it is).
If your mix was already peaking at the top of the scale, there would be literally no space to do these adjustments
without overshooting and distorting the signal. Also, most equipment works best when it's not really pushed to the limit of its performance envelope, so it's best to leave a little more headroom for processing than a little less.
So: the at-least-6dB-of-headroom you conventionally leave in a mix is there to give the mastering engineer space to work comfortably, while also keeping the gear in a good working range.
You may reduce it to 3dB - but you will (potentially) make the mastering engineer's job harder and make certain improvements he would like to do impossible. Or, you may force him/her to gain down your track before applying his/her processing, which reduces the signal/noise ratio and therefore the quality. And like doctors, for mastering engineers it's important to "first, do not harm" (to the signal, not people). 6dB is a good rule of thumb compromise, especially when the recording is already (potentially) as high quality as a 24 bits resolution one.
So that's that. Seldom the mastering engineer will need to use all
the headroom, but it's safe to leave it (or in the ballpark) just in case.
Now, that convention was born in an environment where the final product was generally a CD, so the assumption was that any remaining headroom would be removed by the mastering engineer by limiting the track as the last step of mastering.
Note that "limiting" can be just enough gain to bring the highest peak to 0dBFS - doesn't necessary need to compress anything (and in practice, a very small amount of compression on a few highest peaks would be unnoticeable anyway). A gentle limiting will simply remove any leftover headroom, which is just fine with CDs, which do peak happily at 0dBFS (so long there's no intersample peaks but that's a side benefit of using limiting as opposite to just the gain knob).
With streaming, the expectation is that the track will be attenuated as necessary to hit the target LUFS. Whether not attenuation happens really depends on the material, since as Hugh explained LUFS is a perceptual
measurement, taken over the course of the entire track.
The track may be attenuated, or it may not - regardless if it has peaks near 0dBFS or not.... sure, something that's near 0dBFS all the time
will surely need attenuation.. but it's got nothing to do with the headroom you leave for the mastering engineer.
He/she's gonna need headroom to work anyways.
As of LUFS, it's not something your should really think much about. Just do the best mix you can, have it mastered properly and you'll be fine. If you are interested, I wrote more details on why in my post here