First off, everyone, thank you very much for the help so far.
KEW, I looked and I have a RX-6032V AVR.
Here is what the manual says about the LFE crossover on page 16 (
http://resources.jvc.com/Resources/00/00/97/22026ien.pdf)
FYI, I did not have the LFE ATTENUATE feature engaged. I did not make all of the speakers large when using the JVC so the CROSS OFF light never appeared. To me, the JVC seems to perform the same function as the Marantz does: for multichannel content, the subwoofer was sent the LFE channel plus the content of any channel that wasn't set to large that was 80Hz or below. The crossover on the subwoofer was engaged and set to 90 Hz so all was well, right?
My sub has its own crossover that is set to its maximum and is engaged (90 Hz according to the manual) but I do have the option of bypassing it. It is set to "in" currently.
I always thought that as long as the sub's own crossover was at or higher than that of the AVR, it would have no impact. I had the sub's crossover on while using both the JVC and Marantz AVRs. I've never turned it off because until your suggestion today I've never felt that I had the need to.
Thank you for the graph, that's quite helpful. I will try turning the sub's crossover off when I get home after work.