FluidMoShun wrote:macc wrote:FluidMoShun wrote:
This is probably going to sound stupid, as mixing isn't really my speciality, but why can't you mix all these levels at the same proportions to each other but 5 or something decibels higher?
The answer is in the bit you quoted
Remember that 6dB is half. So if you have one element at -6, that is half your headroom gone. Two elements at -6dB each = all your headroom gone. Having the drums at -3 will leave you fighting against clipping and struggling to keep everything down and under control.
6dB is half of what.. and how does having two elements at -6 (which equals -12) fill up your headroom, if headroom is positive and the elements are negative? Mixing just doesn't make sense to me
I'd stop trying to think about it in terms of arithmetic. Allthough 0dB is your limit, 0dB isn't actually 'zero', its a reference point around which relative amplitude levels can be defined. Technically, measuring amplitude levels in the real world (re: non digital) can only be done logarithmically so '0dB' doesn't actually exist as a quantifiable amplitude (unless your in a vacuum), and the dB levels coming out of your speakers are actually more in the region of about 86dB/Watt at 1meter from the speaker, lowering in amplitude roughly 6dB per meter as you get further away.
Without getting to technical. In digital audio processing 0dB is the (bit width?) limit above which clipping artifacts emerge. Clipping is:
"a form of waveform distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability."
So for sake of ease, and so to be universally applicable to measuring relative amplitude levels, digital audio processing sets 0dB at the clipping threshold. which is as much of an absolute zero as 0 Degrees Celsius.
So when your track reads -12dB its actually telling you the amplitude of that track is 12 decibels below 0dB (remember its just a reference point). If your master buss is reading -6dB then you have 6dB of 'potential amplitude' left to fill before you exceed the limit and clipping artifacts emerge. (
http://upload.wikimedia.org/wikipedia/c ... ipping.svg ~ Pic)
For example, If you have 1 track in your mix and its sitting at 0dB its taking up the entire audio (amplitude) processing capability of the daw. Adding another track to the mix with any kind of amplitude above absolute zero is adding more signal, (All audio signals pass through the master out buss) which will push the DAWs audio processing capabilities past the clipping threshold.
If you take that tracks fader down to -12dB you've just created 12dB of 'headroom' within which you can fit more signal. you can now for example add another track at -6dB to the mix which eats up 6 decibels of your headroom (this track is also incidentally 6 decibels louder than your other track). You now have 6 decibels of headroom, or to look at it another way your master out buss is now peaking at -6dB. You could now add another track at -6dB taking up all of your headroom, or you could add 2 more tracks at -3dB each... so on and so forth.
I've used these figures (3,6,12 e.t.c.) for ease of explanation, in reality, and the idea of mixing, and more importantly
understanding gain structure, is to finely balance the relative amplitudes of each track while keeping the sum total of all tracks below the 0dB threshold. You by no means have to have each track set to -12,-6,-3 e.t.c. in reality its more of a fine tuning balance act with the actual levels being whatever the specific mix needs them to be. Just remember you have a finite work space (the clipping threshold ~ 0dB) and every track adds to the sum total.
hope this helped! Peace.
