Advantages of 4 ohm?

Ok, from what I understand about different impedances the only difference between 2 and 4 ohm is it takes twice as much power to power your subs at 4 ohms as it does at 2. So my question is, what advantage if any is there to running 4 ohms over 2? It seems like a lot more work to me, please show me what I'm missing here.

You've got it backwards. The lower the impedance, the higher the current draw will be. The more current drawn, the more power is delivered. A 2ohm load will draw twice as much current as a 4ohm load. An amp has to work harder when driving a 2ohm load than it does when driving a 4ohm load. Not the other way around.

I see, thank you. My other question is can you still use a mono amp when powering 4 ohm subs, or do I have to switch to a 2 channel?

As long as the load that is to be driven by the amp is within the amp's capabilities it doesn't matter if you use a mono amp or a 2 channel amp.

Ok thanks! I plan on using a JBL BP 1200.1 to power two Infinity perfect 10 subs. The subs need about 350 rms each, and this is just about what the JBL will push out does this sound about right?

With two of those subs wired in parallel hooked up to the 1200.1, they will be getting 600rms each, actually more like 700 because that amp has been bench tested right around 1400rms. You can buy a 600.1 and save some cash, and then they will get around 350 rms because the 600.1 actually benched around 700rms. I recommend you get the single voice coil version of those subs that way you can run at a final 2ohm load instead of a 1ohm load.

2 4ohm subs will make a 2ohm load. 2 2ohm subs will make a 1ohm load. 3 4ohm subs will make a 1.33ohm load, depending on how you wire it up. amps are usually rated down to 1-2 ohms, most are 2ohm stable. if you were to get 8ohm subs you could wire hook 4 up for a 2ohm load. like LS1 RULZ said the lower load on the amp the more power it will push out.

Oh ok well I thought that they would be getting only around 350 rms because the amp is rated at 600 rms at 4 ohm. So how do you run subs in parallel?

You still got it backwards. The lower the impedence, the more juice your amp will deliver. So at 4 ohms, if your amp puts out 600 watts RMS, your amp will be putting out roughly 1200 watts RMS at 2 ohms. Your amp just has to work harder to put out that much power.

Originally posted by Naegash
So how do you run subs in parallel?
Go to JL Audio (http://www.jlaudio.com) and read the "Tutorials" there. You'll find diagrams and explanations on how to connect your subs for the desierd load.

Thanks a lot guys! :bow:

..or can JL at all and save yourself the headache :-D