Mohican question, capacitors.

[Garth Wilson]

Speakers' impedance may be partially capacitive or inductive depending on the frequency of a test tone relative to where the speaker's several resonances and anti-resonances are, and the resistive component won't be the same from one frequency to another either. I've seen Nyquist plots of speaker impedance that were more or less a spiral centered on the X axis as you sweep the frequency range. As far as cutting the cone off a coil, that will change the coil's electrical properties. The best solution would be a transformer. Otherwise, putting a resistor in series may be a good idea. Going straight into the 8Ω speaker with no resistor shouldn't be hard on the amplifier as long as you're not requiring much power out of it.