mix wise we have "only" 4 main core-problems:
(1) level problems
(2) frequency problems (e.g. wrong EQing or no EQing where it was needed)
(3) dynamic problems (e.g. wrong compression or no compression where it was needed)
(4) stereo problems (e.g. wrong panning, stereowidening)
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tips to avoid those problems:
general:
- acoustically tune your room
- get good headphones for crosschecking (i like sennheiser)
- get at least a 2nd pair of speakers, small logitech PC speakers are better than having only one speaker-set
- compare with references mixes, don't use the "loudest" ones, but the quietest ones you can find (so you can see more of the real "mix" due to less limiting during the mastering)
- try to get distance from your mixes, one or two weeks of distance gives sometimes a better view
(1)
- listen on various speaker systems / environments (car, kitchen, mp3 player)
- make level adjustments on small speakers at low volume
- listen in bands. throw in a multiband compressor which is doing nothing & just listen listen the each band and check if the levels for that frequency range is right
- use automation or multing to get the long term dynamics right
(2)
- listen on various speakers if possible
- learn to properly "read" frequency analyzer. check how it should *roughtly* look like from other productions. i'm using voxengo SPAN (freeware). set it to 1/3 octave and find the resonance points & sweet spots with your EQ. resonances are most of the time bad.
(3)
- most of the people have problems to really learn compression. it took me some years to fully understand how & when to use it. its hard to learn & hard to teach.
- stick on simple compressors, like LA2A, they will work ok on 90% of all material
(4)
- learn to properly "read" the correlation meter (check which values are ok from other productions)
- use headphones
last but not least: try to get as much feedback you can get & take it serious, even if it doesn't make sense on first sight.