Here are some speakers that are not well driven by transistors: ESLs (too bright, no bass unless the speaker is only a foot or two from the wall), horns (usually very shrill, due to the reactive nature of the drivers), full-range high efficiency drivers (similar to horns), any box speaker wherein the designer was expecting a power response from the amplifier rather than a voltage response.
An example of the latter is the Wilson Watt/Puppy, which had a resonance in the tweeter. This was controlled by a trap filter set at the frequency of the resonance. This caused a 2 ohm impedance at that frequency (2KHz). Tube amps, encountering that impedance, do not make much power and everything is good. Transistors dump power into that load, resulting in brightness. This is why you see such conflicting opinion on that speaker.
for more info see:
http://www.atma-sphere.com/papers/paradigm_paper2.html
So IME, since I prefer the reduced coloration of tubes, it makes sense to me to choose a speaker that works with that, rather than one that requires a transistor amp to sound right. IOW, that's why you choose the amplification first, then the speaker. Otherwise you can flush some big money down the loo.
An example of the latter is the Wilson Watt/Puppy, which had a resonance in the tweeter. This was controlled by a trap filter set at the frequency of the resonance. This caused a 2 ohm impedance at that frequency (2KHz). Tube amps, encountering that impedance, do not make much power and everything is good. Transistors dump power into that load, resulting in brightness. This is why you see such conflicting opinion on that speaker.
for more info see:
http://www.atma-sphere.com/papers/paradigm_paper2.html
So IME, since I prefer the reduced coloration of tubes, it makes sense to me to choose a speaker that works with that, rather than one that requires a transistor amp to sound right. IOW, that's why you choose the amplification first, then the speaker. Otherwise you can flush some big money down the loo.