DjDanny and Pogre - thanks for you inputs. I am definitely not using LFE + Main for exactly the reason you stated, aka the double bass. Just using LFE via Marantz configuration and via cable connection. I had the LFE crossover set at 100hz in the Marantz because I didn't think it was necessary for sub to operate higher as the surrounds were already operating below that. I wasn't thinking about the LFE channel itself. Now I get what racraford was talking about in an earlier post to this thread. Just made the config change in the Marantz to set the LFE crossover to 120.

djDanny - what do you use to take measurements?