Sorry, I confused myself with my own question
 
 
nevermind
 

it's a common term amongst mixers,
but when you are first starting, it IS confusing.
 
 
zero, typically means level, which means NOT -1db, or +1 db, but 0db, which also means Unity gain.
 
typically, if your individual tracks are sitting around -18RMS, with a decent crest factor, when you bring all the mixer faders up to unity (0db), your master meter MAY possibly be sitting pretty.
 
looking at -10db on peaks, with the RMS around -18 or so.
 
these are just guidelines,
and i routinely surpass them when i'm mixing.
 
in fact, i just finished a mix that i painted myself into a corner on,
and had to select all my Busses (except master) and bring the TRIM gains down all the way across the board, 
just to get some of my headroom on my master back.
 
but that was ok on THIS particular song,
because of the way the tracking was done to begin with.
 
not ok on most of my other mixes.
 

At the risk of further confusion but to add to bats answer - unity is the term generated from the math behind changing gain.  Gain adjustment occurs through a multiplicative function, so if you want to keep gain the same you multiply it by 1.  The dB scale is logarithmic and, as it happens, the log(base 10) of 1 is 0 (hence 0dB or "zeroing" out the fader.)
 
School house rock is over - back your regularly scheduled cartoon.

i jus' crank that m'phucker until it bleeds RED!!!!!!!!!!!!!!!!!!
 
 
 
 
 

We need a "school house rock" forum here....

I am glad to see someone at last has mentioned rms levels.  It goes a long way to ensure all your rms levels are consistent on your tracks before you start a mix. 
 
You need VU metering though to see them properly.
 
The rms ref level can be -18 as mentioned here or any one of the three K system ref levels
 
It does not matter what any effects or effect chains do to gain. All you need to is monitor rms levels going in and out of any effect or chain (if it is a chain in and out of each effect in the chain too) then you will never have issues with effects changing gain.
 
Also when rms levels are consistent on tracks you will never have issues with either too much or not enough level on a track to be able to mix properly.  The fader will usually end up around unity gain anyway.
 
Peak levels tell you nothing about how loud a signal is.  (especially for sounds that have an attack transient)
 
 

HEHEH

It is quite amazing how many people are deaf to great advice re levels within a digital recording system.  It is also amazing how many silly men don't listen to their wives.
 
Dare I say it back in the old days all we had was VU meters and we were only monitoring rms VU levels. We got all our levels nice and even on the multitrack.  All those VU meters just hitting 0 dB VU.  Made it much easier to mix.
 
Why can't the same principle be applied to modern DAW approach.  It can you see. They just took all the VU meters away that is all and gave us peak metering instead.  But you can put the VU meters back in and use the same approach.  It works. And you can use your peak metering at the same time.  Even better.
 
Bat produces some great mixes I agree.  But he is also concerned with rms levels and that is one of the main reasons why I believe.

I normally set Sonar's track and bus meters to peak while tracking then peak (and hold) + RMS for mixing onwards.

I generally pay more attention to how things sound and the RMS than I do peak, but I do want to know if any peaks are being troublesome and need reining in a bit. Plus the final master should peak at a tiny bit less than 0 of course.

I do think the digital sample peak metering can be quite misleading. It's also kind of strange that most meters seem to default to this type metering. It's like they're a glorified clip indicator. I do typically enable Peak+RMS as well.
 
It must have been nice to track RMS levels on VU meter without having to worry too much about overshoots. I've been told that you have quite a bit of headroom before things start to You could err on the high side with analog, whereas it's the opposite with digital. For better or worse, I'm a product of the digital age so that's what I have to deal with. I can dream of a hybrid set-up but I'm not too worried about it for the time being.