I have this hunch that using a standard Cat-5e networking cable to replace the speaker wires would work because wikipedia Twisted-pair says:
twisted pair reduces electromagnetic radiation from the pair and
crosstalk between neighboring pairs and improves rejection of external
Also, instead of just using one pair, you ...
There are two ways to look at this: center frequency and bandwidth.
In FM, the frequency varies as the amplitude of the audio varies. If the audio was a sinusoidal tone, the frequency would vary symmetrically around a center frequency, which is constant. More complex audio is generally still symmetrical. The FM receiver actually locks on to that center ...
"Tuning" an FM receiver sets the center frequency of the receiver, but its internal circuitry is designed to pass enough of the Bessel sidebands produced by frequency modulation of that waveform to be demodulated with low noise and distortion.