There's several charts in the user manual appendix that specify the supported functionality for all sound modes (including direct/pure direct modes). Should clear up a few things here.
For surround sound modes, that is true, but for analog input, direct mode behavior (ref. post#2322), the Denon/Marantz too obviously, has been very confusing on this topic.
There is a thread right here on ASR, it took almost two pages for the OP to eventually figure out what seemed to be a self admitted user error (see post#13 for those interested), and that he thought explained why no matter what settings he used, the crossover settings seem to have no effects.
My Denon AVR seems to ignore any crossover settings and sends full spectrum signals to my front speakers no matter my settings. I have an old Denon AVR 3808ci. I recently bought a pair of SVS SB1000 subwoofers and planned to integrate them with my front tower speakers. I was going to use MSO...
www.audiosciencereview.com
I don't recall if he took measurements for both Stereo and Direct mode to compare crossover effects, but it is clear Denon/Marantz manuals don't clear anything up for those who really want to know the small, large (aka "full"), stereo, direct modes differences in terms of the topic "bass management" that was mentioned by Zwepp triggered my initial response (that seemed premature, so I wish I hadn't responded..) and then
@krabapple continued this discussion with me further.
As the linked thread above did not completely clear things up on the crossover effects in direct mode, I would like to try and see if I could find from my inventory (REW graphs) the sweeps I had done for different crossover settings when I had the Marantz AVP and the Denon AVR-X4400H that I no longer have. If I couldn't find them, or they were only done in Stereo mode, then I would have to do some new experiments on my AVR-X1800H that I used in my two channel setup, but that would be a pain as I would have to hook up a monitor in order to see all the settings.
Just for those curious enough, I had even written to D+M/Sound United a few years ago, about the seemingly functional bass management (again, limited to small/large/crossover only as I mentioned earlier); and their response was clear as mud though at least it confirmed my findings that the small/large/XO thing was indeed functional even in direct mode:
My question to their(Marantz) customer support:
First, my follow up question, after they confirm the ADC/DSP/DAC bypass route in direct mode:
"Thank you for your response. So if in direct/pure direct the signal bypasses the ADC/DAC and DSP, then how come even when direct or pure direct are selected, the speaker distance and crossover settings seem to remain in effect?"
and, their response: Staff Account NJ customer Suppport via Email:
"Looking at the end of the volume IC trace, I do see there's a Tone Control (crossover) which would explain the low frequency output to the sub in Direct Mode."
For clarify, I think the part that D+M has not been clear in their owner's manuals seem only apply to two channels, analog input, Stereo/Direct mode and in relation to the basic bass management. One of origin of the confusion might have been due to, as Gene mentioned years ago, in his review on the AVR-5805 in which he found that:
The AVR-5805 has completely independent bass management settings (ie. crossover, distance compensation, level, etc) for 2CH mode. Not since the days of the Aragon Soundstage have we seen this sort of flexibility, especially in a receiver!
Gene also repeated the following in his later review on the AVR-5308:
Keep in mind that Denon allows separate bass management settings for 2-channel direct mode, so be sure to set that up as well so you get the desired results.
I am not sure if Denon (and naturally also Marantz) has continued the same approach in their current AVRs, but I know my AV8801 and AVR-X4400H appeared to behave the same in Stereo/Direct mode, but again, time permitting I will do some experiments with my only current Denon model, the little X1800H, just to satisfy my own curiosity.