Originally Posted by JHAz
another way to see it is that 0 dBFS is the maximum digital level you can capture. Above 0 dBFS causes digital clipping, and the max level will still be 0dBFS, just with a messed up frequency content. Because digital has this kind of absolute ceiling, levels are referenced to 0 dBFS.
0dBFS is the max you can encode on CDs, DVDs and BluRays. It also is the max that you can encode on digital recorders or digital mixers. I think it's fair to think of 0dBFS as that singla level where the top of the waveform is all 1s digitally, whether it's 16 ones on a CD or 24 ones on a BD or inside a recording machine.* In other words, it is mathematiclaly impossible to encode the LFE channel so that it reaches a peak of +10 dBFS. Just like it's impossible to put a pound and a half of salt in a one pound box. So because the LFE channel might have to keep up with, at least theoretically, 5 other channels at 0dBFS for brief peaks, the LFE channel is mixed and encoded with the understanding that it will be turned up 10 dB more than the other channels when played back. That gives you an additional 10 dB of headroom in teh LFE channel, but the max encoded to the channel is still 0dBFS. It just gets the expected/required 10 dB boost on playback (and during recording/mixing/mastering, so that levels come out correctly.)
*Binary is weird looking. It is the same thing as saying I have a system that can capture numerical values but it has only three places. 000 is the lowerst it can go. 999 is the higheset it can go. I can't encode 1000 because I don't have four places. Digital systems are like this. Their max is defined by the number of bits . . .
That's a revelation for me guys, thanx for clarification. I was under the wrong impression that LFE is mixed 10dB hotter in the movie content. I was so wrong.
So, you guys are saying -10dB LFE offset is already accounted for in movie content during recording to avoid clipping in the signal processing stage in AVR and compensation is not applied up untill the amplification stage. I have iNuke 6000 DSP and um using it to power a ported DIY sub. My AVR is denon 3313. I take the pre-out signal (LFE+Redirected Bass) from avr and feed it to iNuke. How does iNuke know that the input signal is LFE+Redirected Bass and it has to apply 10dB boost at the amplification stage??
I hope um making sense or am I completely crosseyed??
I am asking this coz I manage to clip iNuke at -13dB (Reference Scale) on the avr master volume when dynamic peaks are playing. I know the gain structure and how it works and iNuke is properly gain matched. Sub trim level on avr is at -7.5. The problem is if I reduce it further in avr, I lose all the thump. And if I continue to keep the same sub trim level in avr, it gets clipped. What wrong am I doing??Edited by braveheart123 - 5/9/13 at 2:06pm