Hey guys, I apologize in advance if this is a stupid question.  Anyway, here goes:
 
So I've got my mix perfect to my ears, minus the volume I need.  Anyway, I bounce all the tracks into one, them load them into a new project as one stereo track. 
 
Mix now sounds muddled.  The instruments are all blotched together and I can't seem to EQ it back to where it was.  Doesn't seem to get worse or better when I plug in Izotope5.
 
Any thoughts?
 
Thanks, Keith

Hi Keith - silly thing but try giving your ears a rest. Mix then leave it overnight or a few days before mastering.
 

daryl may be correct but I suggest you figure out why any bounces you do are not sounding the same as the session does when it is just playing. Otherwise you could be chasing your tail. There are reasons why people have experienced bounces not sounding the same as the session itself.
 
Actually to test this you should do a bounce and import that onto a stereo track and just route the stereo track to the main outs directly with no processing on it at all and switch back and forth between the whole session and the bounce to see what may be going on.
 
You may need to review your bounce settings etc..if there seems to be a difference.  If you find there is no difference well it could be your ears as daryl has suggested. Another way to check it is to play both the session and the bounce at the same time but invert the polarity of the bounce and see if you can get the two to cancel out. You may have to juggle the level of the bounce to do it but if it cancels out to almost to nothing then you know the two are the same. If they don't then what is left over may be a clue as to why they don't match so well. Try a real time bounce and see if it happens as well.
 
It is always better to master several days after mixing. Some may not agree but in reality that is what happens with real mastering engineers. They are hearing it fresh for the first time and have not been involved with the mix. If you master yourself you can also achieve this by leaving a week between the two tasks.

Thanks guys, I'll give it a try.

Jeff's right: the first puzzle you need to solve is why your bounce sounds different from what you'd been hearing during playback. Check your routing, making sure that all tracks ultimately end up at the master bus (quick check: mute the master and verify that everything goes silent).
 
Also, there isn't really any absolute need to bounce out the mix and master in a separate project, unless you're mastering an album and want to do multiple songs as a group. It may be more convenient to master a single song in-place, right there on the the master bus of the project. That way, you have the ability to dive back into the mix if necessary, to correct any problems that the mastering process has exposed (or caused).

I agree... the mix should not sound different at all. You have to play detective to find out why it does. I can understand a volume difference but not an EQ issue that suddenly sounds muddy when exported.
 
Rather than bringing it into a new project, do you have or use any sort of audio editor such as Audacity or Wavepad? If so open  the exported wave in one of them to compare. If not, get one as they are both free and well worth having.
 
I open my files in  Wavepad and I know that what I'm hearing is exactly what was exported since Wavepad starts without loading any plugs. What you hear is what you got.
 
You can also import it back into the existing project but be sure to reassign the output of it's track directly to the sound card/interface being sure it does NOT route back through the master again if it has plugs in it. If this is done successfully, you should be able to hear it playing with the master buss muted along with everything running through it.

2 issues at play here..
 
your mixes, and how they are different from song to song;
and your approach to mastering, which includes your tools.
 
as you get better at mixing, your mixes will start to be more consistent, and if you find a problem with one of them, more than likely they all will have it.
 
so, you mixer modus operendi would be my first guess at the culprit.
 
 
then, to do mastering properly, make sure you have the correct tools.
just having izotope, does not mean that it will correct issues with your mix.
 
at the very best, your mastering should sound almost invisible to your mixes.
 
all you want to address with mastering, is the very worst of the things that change when you correct for volume.
and even then, it should be subtle changes, or you are doing something wrong.
 
 

i have a recently self mastered song in the song forum right now...
 
The Road to Tabriz
 
https://soundcloud.com/bats-brew/the-road-to-tabriz
 
 
with this mix, i have recently added a piece of software that i use during mixdown, that helps me with my room EQ correction issues.
 
by using this software, it has helped me dial my room in, which helped me dial in my mixes much quicker and accurately, and this is an example of where i currently am with my mastering attempts.
 
 
this isn't to sell you that software..
this is underline the importance of treating your room for proper mix translations across multiple playback systems
 
i treated my rooms as best as i could afford to, this software was an attempt to bridge my gap, and for me, it worked.
 

My room is actually a big part of the problem.  I'm working on that issue now.