[Thomas W. Bethe]

Bringing in mixes that have already been through a compressor or L-2 type device and are already smashed with the RMS to Peak level being less than 4 dBU.

Adding lots of weird EQ, effects or reverb before sending it in for mastering.

Waiting until the last minute to get the mastering done and then having one foot out the door to send it off for replication.

Not listening to the final mixes on lots of different systems and tweaking it BEFORE sending in for mastering.

Expecting the mastering to work miracles on the mix when the mix is not really ready for mastering,

Expecting the mastering engineer to do the final mixing while mastering, "could you bring up the snare drum and take down the guitar and put the vocalist in the middle of the mix as we are mastering?"

Expecting the mastering engineer to do the impossible... "the bass amp has a problem and every time it is played loud it distorts could you take out that distortion but leave in the distortion from the guitar because that is the way we want it to sound?"

Not budgeting enough for the mastering and say "gee could we do this today and we will pay you when we get the first 1000 CDs sold?"

Not giving the mastering engineer a clear vision of what you want the final CD to sound like. "we know this is heavy metal but could you make it sound like a James Taylor CD?" or "this is the best we have ever played this song but it sounds to tame could you make it hard driving and LOUD?"

Not really understanding what mastering is all about.....