Sounds like the music being discribed was over compressed.

With heavy limiting, the peaks or transients get squashed. with excessive limiting, it will begin to breakup and can get "grainy" sounding.

ok thanks Mike.

How about "there was no transient information"?

Transients are the spike of a sound and are the first things to get hit by limiters. In general when someone says there is no transient information, they generally mean that a limiter was over used and none are left. A compressor with a fast attack can also do the same thing. Drums usually suffer the most as they have a very big spike. So drums without transients sound kind of lifeless.

OK I understand now. thanks Mike.

I also read about processing. One device was a expander and the other was a compressor. I don't hear people talk about expanders hardly at all. Is that process now included in with the newer compressors?

Are mixers & ME folk using the expanders now days?

an expander is the same process as a compressor, just reversed. So expanders are nothing new. instead of lowering the volume above a threshold, it just increases it. Gates are the the same by nature too. All of these process's lower or raise the volume at a threshold point.