Ok - so I should edit on speakers, got it. Any tips on what causes muddiness, so I can prevent it? Or should I post this in the newbs section? I'm kind of new to digital recording... thanks
OK, this may come out harsh, but I am back from a b-day party and have finished a bottle of congnac with a buddy of mine, so I am a bit tipsy. Take that into consideration...
Dude, stop blaming it on digital. Your mix will likely sound even more muddy in analog
Plus, you never, ever fix muddyness issues or any "bad sound" issue in mastering.
You get your tracking right, and you take care of your EQ and sound-fitting in mixing. Mastering should never be about corrective surgery, although that's what it is being turned into for some odd reason.
Stop mixing on headphones. However, I can understand if you HAVE to mix on headphones... I am in a similar boat... whiny neighbors, wife, kid... issues. So you end up using the headphones 90% of the time and then things sound like shit.
If you HAVE to mix on headphones, get ones that are accurate enough, specially when it comes to the low end. Then learn the shit out of them by listening to as many CDs as you can. Even then, you will never get the bottom end right, and you'll likely not get the midrange right either, and it's possible you won't get the high end right and will end up with muffled mixes.
So, eventually you will have to fire up the monitors and at least check your mixes on them. The problem is, if you listen to your headphones most of the time, you won't be learning your monitors as well as you should, so it's likely you'll start "fixing" things that you shouldn't and making poor decisions. Also, there is this misguided attitude that nearfield monitors don't need much of room acoustic treatment, which is far from the truth. You need good acoustics. I used to have weird phasing, comb filtering issues in the mid to high range due to reflections. You move your head slightly and the timbre changes... good luck getting midrange right in that kind of environment.
So... bottom line, treat your room, try to spend some time with your monitors and learn them, and try not to mix on the headphones.