I've noticed most acoustic guitar amps have smaller speakers. I wonder why is that? I have plugged in my dad's Evans custom amp that is very clean and relatively transparent, but it had just one 15 inch speaker in it. It sounds good to me on its own, but I wonder how it would do in a full band situation.
Because most often smaller amps can be mic'ed up, plus they are portable for busking etc? A full stack for an acoustic guitarist would be so much overkill. Just my 2c
For a whole band situation I usually mic mine.
Acoustic amps are usually FRFR. FRFR needs both smaller and bigger speakers to avoid the high and low end rolloff associated with normal guitar speakers. Ie me Peavey KB5 as a single 15'' and a single 4''.