There is only one speaker that I know of that bi-wire or bi-amping would actually be needed.
http://www.reference3a.com/mmdecapo.htm
There is no crossover so full range can be sent to the upper and lower bindings. I believe a resistor or some sort of circuitry is used on the tweeter to send the correct range of frequencies so that the low frequencies will not be played on the tweeter and damage the cone. I believe the full set of frequencies are sent to the woofer.
These speaker were kinda interesting. I demoed this pair ... the sound was very high in detail but I found it very forward (even though the drivers were not metallic). and they are kinda ugly ... looks like a Driod head from Star Wars ...
Saturn
