Need help. Enough power?

[ChaseK5]

Hey guys I have an alpine cde 123 headunit and I am looking to buy two infinity kappa 682.11cf 6x8 speakers. I have the back two 6x8's disconnected and plan to just run the two kappas. My question is about the power needed. Will my headunit supply enough power to power the kappas or do I have to buy an amplifier for them. I'm hoping the headunit will be enough, thanks.

 

[j_garcia]

Continuous output listed as 18W, 50 peak. It is probably enough, but that depends on your listening habits. If you intend to listen loud, you'll want an amp.

 

[BoredSysAdmin]

head full spec is : CEA-2006 Power Rating: 18 watts x 4 channels (at 4 ohms, 20-20kHz, 1% THD)
speaker's sensitivity: 94db and nominal impedance: 2ohm
Now I think there is a thing with running speakers wires in car somehow affects impedance (by increasing resistance??, maybe due to typically low gauge wiring??)
Not sure on this one, but lets assume 18w rms. Plugging the numbers here - http://myhometheater.homestead.com/splcalculator.html
I assume 3ft distance and "corner" placement - i think it's safe assumption for car placement
I get 116db SPL at listening position, which is to say, unless you intend to compete in SPL competition or awake the dead - should be more than sufficient.

 

[lovinthehd]

How does the head unit do with 2ohm? Maybe the speakers are more suited to external amplification...