If you have the sub connected through the sub out jack on the receiver and sub is on in the receiver menu, the sub is getting the full LFE signal but you have chosen to filter it out at the sub for sound above 40hz. On Dolby digital tracks you will get that part of the LFE signal on the mains so you are OK and not losing any information.
Really? You mean the 0.1 LFE that doesn't go to the sub gets routed to the mains? That doesn't seem right, does it?
No that isn't what I meant. If I understand right,
you are engaging the crossover at the receiver at 40hz by setting the speakers to small and sub on. All LFE is now going to sub out. If you had speakers set large, all the LFE would stay in the main speakers. You are also engaging the crossover on the sub at 40hz and the sub is connected to the sub out on the receiver and you have the sub on in the receiver menu.
If you bypassed the sub as is normal, all LFE would go to the sub as well as redirected bass from the speakers below 40hz. By engaging the crossover on the sub at 40hz you are indeed losing LFE information above 40hz that is being directed to the sub from the receiver sub out. In most receivers, in order to get all that info you must bypass the sub or set the speakers to large. I don't have a Denon but that would be normal processing.
Once you tinker with both filters like you are doing because of room acoustics which is cool experimentation, then it seems to me you must go with the Large + sub to get all the LFE otherwise you aren't getting LFE above 40hz. In essense all LFE will stay in the front speakers which you will hear down to the M80s extension at 35hz and the sub will not give you any sound above 40hz but LFE below.
