Tony Prior wrote:
Very true, but lets not lose sight, In the OLD days everyone was recording ANALOG, if you exceeded 0 DB it was a gentle transition past the 0 db point, the audio didn't jump into saturation. Compression was not as important. In the digital domain with todays DAW's , the previous Analog 0 DB reference point has now dropped to - 6 db, thats the so called standard digital audio ref. As we approach 0 DB in signal we get into hideous saturation which cannot be repaired.
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There's just a little too much misinformation ( in bold) in this post to ignore so here I go:
In the analog days (I assume that means tape) there were all kinds of scenarios possible when you "exceed 0 DB". Tape machines could be lined up all kind of different ways, with more or less headroom, different bias curves, etc, what happened when you pushed past 0 VU was a result of many factors, to say it was a gentle transition oversimplifies things. Add shitty analog electronics on semi-pro machines like Tascam and Fostex and you could get into ratty, clipped sounding recordings pretty quickly. Many of the budget machines could barely reproduce the signal fed into them and it wasn't all lovely tape saturation you were getting, far from it. The first time semi-pro studios had recorders that could record signals faithfully was with the advent of ADATs and DA-88s, but at 16 bit resolution and poor dither they too needed dynamics control to achieve hotter levels.
Anyway, in digital the "analog 0 DB reference point" has not dropped to "-6 db", far from it, it is whatever you want it to be . (Truth be told , it was the same way with high quality Reel-to-reel machines and high output tape stock, engineers constantly had to weigh s/n against headroom and lined them up with the headroom they needed/ wanted ).
Most common digital reference levels, aka the point where an analog 0 VU signal (+ 4 dBu, -10 dBv or whatever) equals a given digital signal measured in dBFS (full scale) are -12, -14, -18 and -20 dBFS , not -6 db, as you claim, but there's no reason you couldn't build 30 dB of headroom into your system, whatever you need, assuming your analog gear can keep up.
One really shouldn't record at - 6 dBFS approaching 0 dBFS, there's no need to. A good digital peak level of -18 to -12 dBFS recorded at 24 bits gives you enormous headroom and superior S/N ratio unobtainable with analog recorders.
And your mix should leave enough headroom for the mastering guy to do his work. For that you should monitor True peak levels (usually hotter than regular peak level) , same goes for encoding, it too requires headroom. In short, never get close to 0 dBFS.
So the need for compressors today is less than back in the analog days. Back then you had to print levels as hot as possible and with EQ to get good s/n and printing EQ kept you from raising tape noise by boosting highs during the mix. Therefore you had to contain peaks that might over modulate your input while maintaining hot average levels. None of that is necessary with digital, if properly used. 0 dBFS is not a reference level, it's the maximum level at the AD and DA conversion. There's no need to approach those levels until you get to mastering.