Did a bunch more searching. Dynaqmic EQ is a very poorly explained feature in my Denon AVR; however, I found this in an obscure forum that sets it out for my slow mind:

Audyssey got too tricky with the unfortunate naming of the different RLO aggressiveness settings, so think of them as:

0db = MAX
5db = High
10db = Medium
15db = Low
OFF = OFF

This graphically shows what happens at -10 Db MV & 10 RLO that are my settings right now - read the whole page for more info:

http://www.avforums.com/threads/turning-off-audyssey-dynamic-eq.1155031/page-4

Kinda makes sense now...

TAM