Inpep, with a speaker designed for bi-wiring, the crossover network doesn't bridge the high and low speaker terminals. Yes, they do see the same frequency content. However, the high-pass filter network goes to the tweeter (and maybe mids) while the low pass filter network goes to the woofer (and maybe mids). It is as if there were two independent speakers in the same box - one for highs and one for lows. This is why you need jumpers if you're not going to use the bi-wiring capability. That's the only way both filter networks will be connected to the signal.
The high speaker terminals in a bi-wire setup don't see the IxR losses due to the large woofer currents passing through the wire. (Tweeter currents are comparatively tiny.) The woofer currents are confined to the low wire. It is the same as bi-amping in this respect. Thus the high wire is free from this admittedly small amount of distortion due to the passive losses of the wire. This assumes the amp is a good enough voltage source that it is not affected by the back EMF from the woofer which would then modulate both wires anyway. The wires are not ideal - they have resistance, capacitance, and inductance. You have to consider these properties to understand why bi-wiring works.
As to the audibility of bi-wiring, who knows? I think the effect is fairly small. It would seem that the shorter the cable, and the heavier the gauge, the less difference it would make, assuming the same cable make and model was used in both single and bi-wired configurations. I'll take a better single-wired cable over a lower performing bi-wired cable anyday.
The high speaker terminals in a bi-wire setup don't see the IxR losses due to the large woofer currents passing through the wire. (Tweeter currents are comparatively tiny.) The woofer currents are confined to the low wire. It is the same as bi-amping in this respect. Thus the high wire is free from this admittedly small amount of distortion due to the passive losses of the wire. This assumes the amp is a good enough voltage source that it is not affected by the back EMF from the woofer which would then modulate both wires anyway. The wires are not ideal - they have resistance, capacitance, and inductance. You have to consider these properties to understand why bi-wiring works.
As to the audibility of bi-wiring, who knows? I think the effect is fairly small. It would seem that the shorter the cable, and the heavier the gauge, the less difference it would make, assuming the same cable make and model was used in both single and bi-wired configurations. I'll take a better single-wired cable over a lower performing bi-wired cable anyday.