I need to shop for new speaker(s) to use with an amp head that I have and want to know what to look for in specs of watts and ohms so that I don't blow up or fry anything. My head's specs say "120 VAC, 60 Hz, 600 Watts" and under the Biamp (Low/A, High/B) Speaker Output jacks it says "4 Ohm Min. Each Speaker".