Why do you think Bi-Wiring improves the sound ?

Which loudspeaker manufacturer first put biwire binding posts on the back of their speakers?  Anybody know?

I don't know the exact model, but for the progression, it is one of the rare times I would agree with Paul McGowan, as it is the same story I have heard from truly old-time audiophiles (my dad included) and matched the stories I read. First DIY, with SS base and tube for the mid/highs, and then speaker companies started to build the capability in. It never really took off, but it was a differentiator between cheap and "good".

With one set of binding posts on the speaker end, in theory, unless you are modifying the connections to/thru the crossover, the only benefit would be thicker wire.  If the speaker has 2 sets of binding posts, and they give you a choice of paths through the crossover, then some changed response is possible.  However, dedicating copper to frequency bands leads to less than optimal use of the copper.  At some points in time the base may need a lot of energy from the amp and it cannot make use of the lower resistance that a common thicker wire would provide.

I think there are potential downsides of biwiring. The speaker designer (assuming they are competent) went to great pains to develop a crossover that effectively splits the signal between drivers, assuming the SAME SIGNAL on the inputs to the two parts of the crossover. Anything that might result in a different signal on the two input connections is going to defeat this design effort. 

Now, I suppose, if you prefer the sound from two separate connections to the speaker, then that's really all that counts. But if you are asking a theoretical question, I'd stick with a single connection to the speaker unless it was specific engineered to use an active crossover with biamping.

@bigkidz   Peter external shotgun biwire AQ Type 6 headed your way :-) I am guessing Tuesday you should have them to listen to :-))))) music is the gig - have fun