I need advice on bi amping

Don't bother. Not if sound quality is what you care about. If tech is what you crave, to look cool in the eyes of guys who love gadgets and goo-gaw, then go for it. EQ. The more the better. 

If sound quality is your goal however then use whichever amp sounds the best, sell the other, and count your blessings you were smart enough to not get sucked into the vortex that is bi-amping.

what is the best way to go, vertical or horizontal?

Go vertical, put the amp close to the speaker, use shorter speaker cable.

What "more" are you looking for?
Bi-Amping can often bring some benefits if you are taxing the amp with bass, but with the subs, I would assume you are not pushing the amp very hard?

It's an old amp, lot has changed. If you feel you must have a new amp, but a better one and sell the Quatre DLH 100 while it has value.

Thanks for your collective input. Perhaps I am being sucked into the vortex. I have yet to turn it up past half volume, so maybe I am just being a "look at my massive system" guy, though I am literally the only person who ever sees it (the neighbors hear it sometimes). The specs recommend 250 watts and I am pushing them with 100 a side. 

I am running a pair of re-built Veritas 2.4s. Would bi-wiring them add an appreciable difference? 

I am sure there will be many different opinions, but unless you have inadequate wire, especially thin gauge, bi-wiring is unlikely to offer much if any improvement.


Ignore the specs for power on the speakers. They tend to be a bit meaningless and depending on how big your room is, 100W in an amplifier with good "reserves", i.e. able to push higher than that for peaks, my be more than sufficient for the volumes you achieve without pushing into clipping.


If you want "loud" then there are speakers for that. If you want "good", then room treatment, perhaps an amp upgrade, etc. etc. are better places to spend your money.