1. The disorienting room space.This comes from using too many reverbs: a silky plate on the voice, a big room on the snare, shorter delays on guitar . . . concert hall, or concert hell? Even if the listener can’t identify the problem, they’ll know that something doesn’t sound quite right.
Solution: Choose one reverb as your main reverb that defines the characteristics of your imaginary “room.” Insert this in an aux bus. If you do use additional reverb on, say, voice, use this second reverb as a channel insert effect but don’t rely on it for all your vocal reverb; make up the difference by sending the vocal to the reverb aux bus to add in a bit of the common room reverb. The end result will sound much more realistic.
2. Failure to mute. All those little pops, snorks, hisses, and hums can destroy a mix’s transparency. Even a few glitches here and there add up when multiplied over several tracks.
Solution: Automate mutes for when vocalists aren’t singing, during the spaces between lead guitar solos, and the like. Automating mutes independently of fader-style level automation lets you use each for what it does best.
3. “Pre-mastering” a mix. You want your mix to “pop” a little more, so you throw a limiter into your stereo bus, along with some EQ, a highfrequency exciter, a stereo widener, and maybe even more . . . thus guaranteeing your mastering engineer can’t do the best possible job with a fantastic set of mastering processors.
Solution: Unless you really know what you’re doing, resist the temptation to “master” your mix before it goes to the mastering engineer. If you want to listen with processors inserted to get an idea of what the mix will sound like when compressed, go ahead—but hit the bypass switch before you mix down to stereo (or surround, if that’s your thing).
4. Not giving the lead instrument enough attention. This tends to be more of a problem with those who mix their own music, because they fall in love with their parts and want them all to be heard. But the listener is going to focus on the lead part, and pay attention to the rest of the tracks mostly in the context of supporting the lead.
Solution: Take a cue from your listeners.
5. Too much mud. A lot of instruments have energy in the lower midrange, which tends to build up during mixdown. As a result, the lows and high seem less prominent, and the mix sounds muddy.
Solution: Try a gentle, relatively low bandwidth cut of a dB or two around 300–500Hz on those instruments that contribute the most lower midrange energy. Or, try the famous “smile” curve that accentuates lows and highs, which by definition causes the midrange to be less prominent.
6. Dynamics control issues. We’ve already mentioned why you don’t want to compress the entire mix, but pay attention to how individual tracks are compressed as well. Generally, a miked bass amp track needs a lot of compression to make up for variations in amp/cabinet frequency response; compression smoothes out those anomalies. You also want vocals to stand out in the mix and sound intimate, so they’re good candidates for compression as well.
Solution: Be careful not to apply too much compression, but too little compression can be a problem, too. Try increasing the compression (i.e., lower threshold and/or higher ratio) until you can “hear” the effect, then back off until you don’t hear the compression any more. The optimum position is often within these two extremes: enough to make a difference, but not enough to be heard as an “effect.”
7. Mixing in an acoustically untreated room. If you’re not getting an accurate read on your sound, then you can’t mix it properly. And it won’t sound right on other systems, either.
Solution: Even a little treatment, like bass traps, “clouds” that sit above the mix position, and placing near-field speakers properly so you’re hearing primarily their direct sound rather than any reflected sound can help. Also consider using really good headphones as a reality check.