Stock radio with/

I currently have Infinity 7540a.

http://www.crutchfield.com/S-FV5O9En8Crg/c...120&I=108R7541A

In the doors I have Polk db650's.

And I was looking at keeping with the polk line and go with the Polk db124

http://www.polkaudio.com/caraudio/products/subs/db124/

2 quick questions. What the hell is the difference between 2 and 4 ohms and will this sub work well with this setup in my trunk well.

 

That's a good choice because you can get it for < $100 and it only needs .88 cu. ft. You probably want the 4-ohm version if you are going to use one sub, unless your amp can run at 2-ohms bridged.

 

A lower resistance allows a larger amount of current to flow. Resistance is measured in ohms.

So if you have a sub with a 4 ohm woofer vs. a 2 ohm, assuming they have been wired correctly and are being powered by the same unit douring the test the 2 ohm will be 'louder' and put out more SPL.

If you can get yourself the dual voice coil version, you should be able to wire it to run 2 ohm... again assuming your amp can handle that.

 

Do I need a tri-way Crossover?

http://www.crutchfield.com/S-IY4Iw6mTG7V/c....asp?i=127TM100

I also was looking for something to be able to adjust the bass control? Anyone know if I can use it on my amp and where to get one?

 

You wouldn't really need a cross over, but I would get an aftermarket HU, the factory would need a line level adaptor and the sound wont be as good compared to an aftermarket.

As for something to drive the bass a little harder/ control its output remotely...I used an Audio Control Epicenter in my Blazer, but I don't thing you would need anything like that in a car this small. You could ask the crutchfield folks if there is a control available from the manufacturer.

 

While a lower resistance does allow a higher current, that does not always translate to more power in the circuit. This is one of the most basic misconceptions in circuit design. You need to match the load (speaker) to the of the impedance of the supply circuit. On some home receivers you may find a switch on the back to set this based on the speaker setup you are using, and this is why.

Since power is what you want to maximize, you need to load match to maximize "loudness"

http://www.allaboutcircuits.com/vol_1/chpt..._power_transfer

The DC concepts covered there translate to the AC frequency domain directly.

 

Yeah I know that's why I said what I did

 

Yeah I know that's why I said what I did [/QUOTE]
From the Crutchfield link:

"

 

Did you even read what I said at all?

I guess I need to clearify it a little. If you wire the sub and the amp the same way the 2ohm sub will be louder. Also the amp impedence and the sub should match and should be wired correctly.

Your talking about 2 different thing quoting that from Crutchfield. Your talking about it being wired differently. If have an amp that can run either 2 or 4 ohm loads the 2 ohm loads will be louder. The quote you have basicly states that if you rewire it, it can be louder this way or that.

 

Maybe take a look through this page from Crutchfield here. It has some more info on it. But that page better discribes my point. Maybe I wasn't clear enough... even trying to clear it up. I quoted it from Crutchfield because you seem to trust them as you quoted them yourselves.