Maril555, we did run into some problems with silver-plated wire and it was both brightness *and* dullness! A lot seems to depend on the wire- its gauge, how its extruded, purity, the thickness of the silver plate, etc. We've heard some that are just fine (Purist made some wire for our use at one point). Copper is a lot easier- just make it pure and don't make the gauge too big :)
Saki70, the Voltage Paradigm showed up about the same time transistors did. I'm sure that's not coincidence!
In a crossover wherein the speaker designer uses series elements to cross over the driver, the actual crossover frequency can change a little if care is not taken to be sure that the upper and lower rolloff points in question do in fact crossover enough! IOW, you often need a dip in impedance at the crossover point in order to be sure that the crossover will be effective. This will cause a loss of power in the amplifier at about the same point that both drivers will be running, hopefully resulting in flat frequency response. Its a matter of taking care- the same scenario might not work so well with a transistor amp- the crossover point might have to be adjusted.