Mordante, if the current for all frequencies flows in a common cable, magnetic fields are generated by the current for all frequencies. As a result, the relatively large current in the bass can modulate the higher frequencies.
Typically, the high-pass crossover has high impedance at low frequencies. In a biwire connection, the cable to those drivers will have little to no current flow of bass frequencies and with that, there will be little or no modulation of the higher frequencies.
Of course, if the speaker designer doesn't implement high-pass crossovers with high impedance in the excluded low frequencies, this benefit won't be realized.
Typically, the high-pass crossover has high impedance at low frequencies. In a biwire connection, the cable to those drivers will have little to no current flow of bass frequencies and with that, there will be little or no modulation of the higher frequencies.
Of course, if the speaker designer doesn't implement high-pass crossovers with high impedance in the excluded low frequencies, this benefit won't be realized.