I have an old 1x15 Acoustic 136 combo at my g***r player friend's place.I blew the driver,a 15,and replaced it with an 8 ohm Eminence 15. I also have a smaller 1x15 85 watt combo made by the defunct "Rock" amp co.that I use for practice.the Rock amp puts out it's 85 watts into its 4 ohm driver. Since the acoustic's brains barely work and distort badly I was curious as to how the new driver (in the acoustic)would sound when powered by a good ,if slightly weak head. So side by side ,I played through both cabs,the larger cab wth the 8 ohm and the smaller with a 4 ohm.The results were the cabinet size had much more of an effect than impedance. The big cab was louder and much deeper and clearer sounding than the smaller cab even given the smaller cab should have been drawing more current or watts from the head.It is a solid state head BTW. Also,I was delighted that the new driver worked well with the old cab.Now all I need is a head to take over there when we jam.