The speakers, by nature of their bigger magnets, larger voice coils, more coil windings, heavier cones, etc.. are less effecient. It is a trade-off that is usually made in return for better cone control(less distortion) and higher power handling. Ultimately, with added power, this results in a much more accurate speaker and louder sound reproduction capabilities. But, with stock power, the biggest result is lower volume.

I run into this scenario daily at my store. Most people do not understand why the car isn't as loud after the new speakers on the stock system...the average wanna-be audiophile relates loudness to quality, so they think the new speakers are a "ripoff" since they cannot play as loud as the inferior factory speakers with 3-4watts rms from a factory headunit. Kappas, like most aftermarket speakers, need around 75-100watts rms to play in the comfort zone and reach moderate playing levels.

 

Right. Which is why I will be adding a 4x200 RF amp. But with a 94db sensitivity rating it shouldn't need as much power as the average 80 - 87db speaker.

 

I agree the 94 db sensitivity rating will require less power to sound good. I would also install baffles which will keep them safe and clean. Not to mention improve your bass a little.

 

Or, the "94db" sensitivity rating could also mean that it has bad frequency response (a rather large peak at 1khz). Sensitivity ratings are mostly useless and are a very poor way to judge a speakers overall output capabilities. Remember...sensitivity ratings are referenced to 1khz (not the full average frequency response capabilities of the speaker) and measured using 2.83 volts ac (roughtly 1 watt). Most factory speakers simply do not get much louder after the speaker reaches x-max (full linear travel of the cone) and that is generally with about 5 watts. Well designed aftermarket speakers are capable of getting MUCH louder since they actually convert more AC voltage to actual usuable sound output.

A factory speaker might perform as follows:
1watt...94db
2watts...97db
4watts...100db
8watts...101db (due to powerhandling and compression)max(ish)

a quality aftermarket?
1watt...88db
2watts...91db
4watts...94db
8watts...97db
16watts...100db
32watts...103db
64watts...106db
132watts...109db

The percieved loudeness of the aftermarket will be roughly twice as loud as the factory given good clean power of around 100watts rms. Remember, it takes double the power to achieve 3 db increase in output, but it takes 10db for the human ear to percieve the sound as "twice as loud".

 

Excellent feedback. Thanks!