Speaker impedance always seems to be specified in binary orders of magnitude; 2, 4, 8, 16, 32 ... can it go higher ... 64, 128 ... why is it binary? what does it signify in the real world in terms of a speakers sensitivity or sound? Or is it even relevant?
Or at least, the taps on amps seem to increase in binary order of magnitude fashion. 2, 4, and 8 ohm taps are common. Some amps have taps for 16 ohm speakers. The McIntosh 275 can be used with 32 ohm speakers in mono mode, and I presume there are others that can do the same. I've never heard of speakers with that much impedance before. Do such exist?
I would think that speakers with low impedance would be easier to drive than speakers with high impedance, and might be louder at any particular output wattage. But from my reading thus far, I get the impression that speakers with higher impedance are preferred. Why is that?
I'm really just trying to understand why the resistance of speakers matters, and the reasons for the binary progression in impedance.