I have heard something about needing to match the impedance of my amp with the impedance of my speakers.

The head unit (Kenwood DPX-701) I am look at is 22 watts RMS x 4 channels, with an impedance of 4 - 8 ohms (I had to go digging in the PDF manual to find the impedance).

The speakers (Infinity Kappa 682.7cf) I am looking at are 2 ohms. I plan on getting a set in the front and a set in the back.

Will this work?

If not, what impedance do I need on my speakers, and how do I calculate it?

 

the impedence value in ohms of the speakers needs to be matched to the amp. Your deck is not rated at 2 ohms, and probably will not like 4 - 2 ohm speakers on it. This will cause the amp to run hot, and could blow. Those speakers are really made to go on an external 4 channel amp, they probably have the same speaker in a 4 ohm version that would be better on the deck.

 

Impedence is a measure of resistance. Your deck doesn't have any impedence, that is telling you the power output at the different impedances. As the resistance changes the power output changes. The deck is made to operate within a 4-8 ohm resistance. If you hook up 2 ohm speakers to it you will cause it to run hot and prematurely fail.