Mix Records on Crap Speakers.

"It's the very naive producer who works only on optimum systems." -Brian Eno

It's unlikely whoever is buying your records has anything better than an average hi-fi, boombox, car stereo, or ipod. I'd bet they don't have studio monitors.

Recording & mixing solely on studio monitors is foolish. All that low end in the guitar? It's useless in the small speakers. It's just taking up frequencies the bass or drums or organs or tenor instruments can occupy. You have to be ruthless in cutting away useless frequencies so the record is loud & jumps out of all speakers. Make the record sound outstanding on little crap speakers since that's where most people will hear it. I've found when I do this it still sounds great on the fancy speakers.

"Some years back I had a lot of success with a pair of Auratones strapped in
parallel to a pair of Radioshack speakers. That's the rig I used for the making of Peter Gabriel's So album." -Daniel Lanois

If you consistently have these mixing problems try using small speakers...
the bass drum disappears in your car
the vocal level is not where you expected
the guitars are lumpy in the low-mid
any reverb or echo is surprisingly quiet
anything you thought was subtly in the mix is actually inaudible

I haven't ever bought expensive crappy speakers like Auratones. I just use crappy speakers. You know, radio shack, bose, whatever.

be good to yourself,
Bill