Let's now talk about what you should expect from a "mix review" session the following morning.
Firstly, try to do it by yourself with perhaps just one other person present. Having an experienced person who wasn't there last night can be helpful - perhaps an experienced mixing colleague?.
The aim of the morning review, is simply to confirm that last nights mix was good enough. The aim is not to make any changes whatsoever unless something is badly wrong. Even if the person reviewing it with you suggests some changes, do not make them blindly without question - they may be wrong in their opinions.
If you work in software development, you'll realise that this "morning after" process is a lot like fixing final bugs before a major software release - i.e. you do the minimum amount required to fix a bug - and that's assuming that you even decide to fix it at all. If it isn't critical, then leave it well alone. The last thing that you want to get into is dismantling everything. Most of all, you need to avoid "chain reactions".
What's a chain reaction? A "chain reaction" is where you start making changes that have impact on other things, requiring them to be changed, which has impact on further things and so on. Normally the conversation goes something like this:
"Ooo - we ought to turn up the percussion just a tiny bit"
"Yes, let's do that"
"Ah... the snare sounds too quiet now. Can you brighten it?"
"Yes. We ought to consider using a different effect on them..."
Before you know it, everyone is taking the mix apart, and redoing everything. All this because you thought the percussion was a tiny bit too quiet. Was it worth it? The chances are, that once you let this happen, you'll be in the studio until the early hours of the next morning yet again, with no guarantee of a better result.
The way to avoid this, is first of all to consider whether it is really critical that you make any such change in the first place. Can you live with it how it is? It's fine to be a perfectionist, but playing with the mix after you've "finished" it, can have lots of subtle side effects that you forget in the cold light of day. Maybe (in this example) the percussion was a tiny bit too quiet deliberately because you found out - last night - that it was interfering with something else?
It is very easy to forget the reason for things on the morning after. Leave it alone if you can. If you must make a change, then the moment you realise that your change is starting to interfere with something else, then you should put it back exactly how it was. Don't go "unbalancing" all the hard work you did yesterday.
Not only have I seen this happen several times before, but I've also known several times where the revised mix at the end of the "mix revision" day (after many more hours tweaking) sounded much worse than the original mix did the night before!
Learn to trust what you did the night before, and the only changes you should make - if at all - is to fix "major bugs" only. That's the point in leaving it overnight - just to check in case you'd gone completely mad due to tiredness the night before. If the mix sounds pretty good then just leave it. Don't start tweaking all the faders again.
For this reason, try to avoid "inviting" important people to audition the mix in the morning. They can listen to it later. The morning session is for you alone (and perhaps a trusted friend or colleague). The last thing you want is half the band turning up, along with all the record company representatives. Before you know it you'll have every fool playing with the faders trying to make their mark on the mix. The mix is finished at this point and should be considered sacred unless something is badly wrong.
If you feel that you must make changes to the mix, before you do so, it is vital that you compare the mix you did last night with how it sounds this morning. The two should - naturally - be identical. Play them back simultaneously and switch between them making sure that they are identical in every respect before you start to change anything. Better still, on an all-digital digital system (a trick I've only discovered recently), blend last nights mix out of phase with the mix as it is now. The two should cancel out and you should hear total silence (apart from any effects or reverb that have a degree of randomisation in their behaviour).
I've nearly sent a mix (on more than one occasion) with "just one change" off to the mastering room, and then discovered (at the last minute - whilst waiting for the taxi to come and take the tape to the mastering room), that the mix is missing an important instrument because a "mute" button has somehow accidentally been knocked between the night before and now, or that an important effect is missing because of a dodgy patch cord. So you can understand why I stress that ideally you should leave the mix well alone, rather than make changes.
If - a couple of days later - you genuinely feel that some very slight tweak is really necessary, just mention it to the mastering engineer, and they will EQ, compress or otherwise process the final mixed stereo recording to bring out (or suppress) the things needed in order to get to the result that you want. At this late stage, this tends to produce better results than making ad-hoc changes to the mix setup itself, and because the entire mix is being processed, it tends to minimise the "chain reaction" effect that can otherwise occur as a result of trying to re-balance the original mix faders. It's also beneficial in the sense that the mastering engineer will be hearing the mix with a totally fresh set of ears and may even urge you to consider leaving the recording alone if they believe that the balance is good enough without further reprocessing.
In some ways, mastering engineers are the "doctors" of the mixing world: "Doctor, I think my mix is unwell!". "Really? Let me have a look... I see... That's nothing serious, so try not to worry. Just take two of these frequencies and see me in the morning..."
Mastering can be a very reassuring experience.
I hope this article has given you an insight into the art of mixing, and that it helps you create great mixes in future!