I've always wondered what the DIN audio spec standards are but didn't find much in searching.
In this thread it's apparently footnoted for some Paradigm speakers/subs as DIN 45 500, which apparently is -3dB in a "typical listening room". Here's
a review I found with some measurements, and
another here.
Some subs when you use a dedicated LFE input bypass the low pass filter on the sub, but to be safe just turn it to max value when using your avr for bass management....check the manual.