palbert: I assume that the front left channel connects to the left speaker (bottom posts) and the surround back left channel also connects to the left speaker (top posts). And vice versa for the right side. Does this sound correct?
I'm still a bit confused, in part because I'm a simple 2-channel person and this other stuff isn't something I'm experienced in.
So, with that said... this is what I'm hearing you ask, am I correct?
Your Denon has let's say, 4 channels of output. Front left, front right, rear left and rear right.
You are asking if "biamping" is taking the front left to the (example) upper post of your left front speaker and the rear left from the Denon, to the LOWER post of your left front speaker?
If so, how are you dealing with the probability that the front and rear channels MIGHT have different sources playing at the same time? Or, can your Denon, allow you to redirect the signal, such that the rear left and the front left are the SAME signal??
If I'm catching what you're trying to do... I'd say, not only is it NOT "biamping" in the true sense of the word, but it might give you weird results by having different outputs playing on the same speaker.
So, to reiterate... if you want to biamp and do it properly.... then you would first, ascertain if your speakers allow you to remove those straps on the inputs and send a divided signal to them (I think it's reasonable that the answer would be yes?)
Then, you'd take your front left output, send it to an active crossover which will split it into TWO signals, one HF and one LF and you will then take these two parts of the signal and feed them into their OWN individual amp (stereo or mono) and then connect that amp to the speaker inputs. This is where the term "bi amp" (as in two) comes into play....using two amps for the one speaker. Triamp is three amps on one speaker
There are other versions of "biamping", often called "fools biamping". I'm not terribly well versed in those but usually, as I understand it... you'd take that strap off your speaker and take your signal from your Denon's amp and put TWO speaker wires onto it (two sets of speaker wires for ONE speaker). You would take one lead and put it to the lower posts and the other lead to the top posts. You are essentially, feeding each set of speaker posts, the SAME full signal, as sent by your amp/Denon. Some people claim they hear this & that. Others call it fools biamping. Call it what you will...
If you want to do "true" biamping, then you need TWO amps for each speaker and an active crossover ahead of each amp to split the signal into LF and HF signals for each amp.
Now... here's a twist.
I've got an old Yamaha AVR and if I recall correctly (been years since I've looked at backside of it)... each channel on it has a line out and a main in. I could in theory, take the front mains line out, put a splitter on them and patch them into front mains main in as well as the REAR's main in. I would then have the same signal coming out of each internal amplifier as though I had TWO sets of front main speakers. I still have the problem of a full spectrum signal being sent out from the amplifier but be it as it may... you could do this and send one to the LF input and one to the HF input. At least, this way, you'd have the proper front signal going to the speaker HF and LF inputs and ....maybe divide the workload between two amps but the speaker inputs are both STILL getting a full signal which sort of defeats the purpose of biamping. (do you really want to send your LF signals to your tweeter and risk blowing them out?)
and what else...
heck...
Seems like an aweful lot of work to try to gain something (what ARE you trying to gain?) and even if you did do this...you'd STILL not get the TRUE benefits of biamping.