This is the most MIS-UNDERSTOOD process of studio recording. Many people think the day you record your song it’s finished. Some people want to track, overdub and then mix it all in the same day. Your mix may sound OK but it’s the wrong thing to do. Mixing a song could take a few days when done right.
Mixing a song requires that the engineer step away from the song for up to 3 days and then mix it.
Because the engineer needs time to refresh his/her mind as to what it sounds like. This allows for a fresh perspective on what the song sounds like which means the mix will be much better than doing it right recording it. But it seems artist that come to the studios think the song is finished when they are finished with their vocals.
Some studios will mix your song right after you record it and hand you a “FINAL” mix before you leave. In my 40+ years of audio engineering this has proven time and time again to be the worst thing that engineer could ever do for you. But then and again some artist really don’t care about doing it right and have no problem wasting their money going to a studio and getting a rushed unprofessional mix of their song so it happens quite often.
Here are my BARE MINIMUM recommendations:
1). If you are recording to a 2-track (a song instrumental), the average time to mix could be from 15 minutes to an hour per song depending on the amount of vocal tracks are used.
2). If you are a live band this could take up to 4 hours per song plus a day or two to “refresh” from the song and make tweaks to the mix. Please note that live band recording also requires and hour per song for editing such as cleaning up vocal takes, headphone leakage, drum bleed over, and more.