Hi my mate just gave me a 4 channel (150x4) amp that he says is from america. The brand is audio mobile acoustic..i cant find out anything about it. Anyway my problem is i want to get a sub, will this amp be enough to power it and if so what type of sub will i need ie. 4ohm or 2ohm. The amp is bridgeable as it show a little diagram next to speaker out puts and it has a switch on the other side which can be used to select between 4 channel 3 channel and 2 channel, how should i have this set for various setups??? My final problem is the X-OVER if i use only one sub and power two other speakers i cant have low pass for better bass, does this mean i should use the amp for either subs or speakers (ie dont mix subs with speakers). Any help would be greatly appreciated. thanks