Re: Whats the difference between a 2 & 4 ohm sub and the effect on the amp?
You wouldn't if you don't want to. That's just showing what the amp is capable of, and it helps you with flexibility.
Say you have an amp rated for 1500@1ohm and 1000@2. Right now you have two subs rated to do 750 each, so you hook them up and have a great time. But for whatever reason you want to scrap those and just get one sub. The one you want, having listened to a bunch, is rated at 1000. So you get the dual 4 model and wire it at 2 ohms, so now you're giving that sub its rated power and didn't need a new amp.
And now... now, what joy will I have left to live for?