I think the bad mastering of many early CDs is mostly because mastering engineers didn't know how to master CDs. They were still employing the same techniques t

I think the bad mastering of many early CDs is mostly because mastering engineers didn't know how to master CDs. They were still employing the same techniques they'd been using for vinyl, where they were hardly applicable. (I think that's where the RIAA curve thing comes from, which is unlikely to be literally true as the RIAA curve would remove almost all the bass from the recordings.)