For some reason I never have compared my mixes to CD's. It always seemed to distract me too much from what I was trying to achieve. Lately however, I have been playing CD's during my mix sessions, but not for referencing bass or vocal levels. I have been really enjoying playing stuff to get fresh insights on just overall "vibe".
IMO opinion, if your mixes are pretty close there shouldn't be a massive difference between a mastered CD and your mix, but don't fall into a trap of trying to give it as much level and sheen as something that has been mastered. This probably makes no sense at all.

IMO opinion, if your mixes are pretty close there shouldn't be a massive difference between a mastered CD and your mix, but don't fall into a trap of trying to give it as much level and sheen as something that has been mastered.

Yeah, I never really use bus compression on the 2-mix when I print (far be it from me to pretend I'm a mastering engineer).... but for monitoring purposes, I feel like I gotta put *something* on there while I'm A/B'ing with a mastered CD, just to get that 'pump factor'... so that my mix-in-progress doesn't fall completely flat next to a Lord-Alge mix (or what have you).

Of course then you get into the whole question of 'mixing to the compressor'... I often find I bump the drums way up while listening thru a bus compressor, cuz I really like that smackier sound when it hits the comp harder. But then again, I don't wanna make assumptions about what the mastering guy is gonna do to my mix later on. Nome sayin'???

So getting back to my original question, do you guys generally not make a habit of A/B'ing your mixes with mastered stuff? Or if you do, how do you handle that level differential?

I don't compare my mixes while I'm doing them. I like to stay with what I'm doing, and hopefully let the track talk to me. I then try to achieve what it's saying. If I compare to other things, I start to use the ideas that are that mix. I'm trying to work with the tune at hand, which may not benefit from what might be perfect on someone else's song, or mix.

My$.02

I highly recommend printing mixes with 2-bus compression over waiting for mastering. Compression drastically changes balances. Why would you want to spend 16 hours mixing, to have some guy change all your balances?

Remember, compress when mixing, limit at mastering. Limiting doesn't change balances. Excessive limting removes depth from a mix. There are some guys that limit so much that you could hang the mix on a wall. Don't go to them.

I only compare mixes the first few days in a room I'm not familiar with. And I always check against my own mixes because I'm so familiar with how they sound everywhere. Once I have my gauge, I don't compare anymore. If you're not sure, there's nothing wrong with checking against a CD you're familiar with. Just try not to compare apples to oranges (i.e. a super sparse mix to a highly dense mix).

Mixerman

I agree with Mixerman, a little bit (or a lot), of 2-bus compression is usually a winning thing. The trick is, you have to be experienced enough to not degrade your mix, by using settings that enhance what's happening in the track. After mixing for more years than I care to admit, and making all the mistakes that can be made, I now have almost no preconceptions about the role of 2-bus compression. I think the learning curve might go something like this. Learn to make your makes sound damn good with no overall compression. Then go through a period of seeing what a good stereo compressor can do for you. These days, if I'm mixing a complete record, I might use no compression on some songs, and a little or a lot, on others. I also play around with different compressors on the stereo bus to see what works on various songs. Mixerman is right, don't monitor your mixes with compression, just use it or not. The limiters a good mastering engineer would use won't change the mix like the compressors you are monitoring through. A good way to simulate mastering limiting and/or level increase, is to record your mix to an Alessis Masterlink. Use the DSP limiter to crank up and brick wall your mixes. It's fun too! Just don't encode your master mixes with the DSP. I hope this makes sense...

I don't often use 2-bus compression, but I wouldn't monitor a mix through something I was not going to use- it's just going to give you a misleading impression of your mix. I also don't compare CD's much anymore. When I did, though, I brought the CD player in to the board through a couple of channels or an aux return, and turned it down to be in the same ballpark as what I was mixing.

The more you get to know your room and monitors, the less you will find yourself needing to compare CD's with your mixes.

I am actually really enjoying the gradual changeover from putting commercial CD's on my studio monitors so I could get to know what the monitors are telling me, to putting them on and being able to confidently hear their strengths and weaknesses, because I know the monitors. It's taken a year or so, and I am still learning them.