Hmmm Phase man which ones did you think are flat sounding ?
As far as sound quality most of them seem real good , in the last six months Ive bought 5 of them . I find myself playing Back on Black the most becuause its the best collection of music on one disc to my ears . Last night after I read this I played "For Those About to Rock" and the sound quality was real good. Of course they have alot in the catalog and they were digitally remastered from the orginal master tapes spanning many years so its possible a few of the master tapes are mediocre, but so far The sound quality has been great on the ones Ive purchased.