[onewhippedpuppy]

Originally Posted by Eric Coffey

Yep, the dB rating = sensitivity (typically expressed as dB level of a 1 kHz test-tone using 1 watt, at 1 meter away). Anything over 95 dB is highly efficient/sensitive. The thing to consider is that high sensitivity is typically achieved from using very lightweight cone/surround/spider materials. As a result, a lot of "high sensitivity" speakers are good at playing loud, but often at the expense of frequency response/bandwidth (specifically no lower end), and noise distortion. If you have any system-induced noise (internal amp issues in the head-unit, electrical/alternator noise, etc.), then a highly efficient speaker will amplify that noise that much more.

So, everything is a trade-off. Though, I would agree with Matt, that if you are sticking with a 70's Blau head-unit (likely 10wpc or less), then I'd probably lean towards speaks with a higher sensitivity rating.

Ditto to what Eric said. Both the Infiniti Reference and Kappa speakers are 3 ohm, and both have very high sensitivity values, with the Kappa being slightly better. I would have probably bought the Reference at about $20 less, but they were out of stock and the Kappas were available. The Kappas have a tweeter that rotates so you can better "aim" the higher frequency sound, which I also found useful in my door mounted location.