Efficiency isn't the main issue. It comes down to sound quality, and the measures associated with it: better frequency response and dynamic range. Then the subjective measures: clarity, fullness of sound, imaging, sound stage, etc...
Bottom line, it sounds better.
Why? well, first it has a separate high frequency driver. Upper end response in the factory speakers is quite paltry. The horn in the 1695 offers excellent dispersion, and a very natural, "open" sound. The factory door speakers just don't reproduce these, and the dash tweeters, IMHO are useless.
Next, bass response is better. Now, at lower volumes, the factory door speaks perform OK for bass, but turn it up, and they bottom out (reach their excursion limit) and sound terrible. Probably the single biggest complaint with the factory setup among Ody owners. Of course the head unit is a little underpowered, but for most, that's not a huge deal; the speakers are definitey the bottle neck in the chain here. If you read back in one of my previous posts, I made the observation that after switching to aftermarket speakers, I was actually able to get the factory head unit to compress significantly at high volumes, something that doesn't really happen with the factory speaks since people usually stop turning the knob after the speakers start to distort due to their inherent mechanical limits.
Then I could talk about log scales for dB, how you need 10X power for 2X loudness (+10dB SPL) etc... blah blah, but I think you get the picture.
The speaker harness adaptor converts the proprietary Honda speaker connector to standard spades that can be plugged into most aftermarket speaker terminals. They are right at the speaker end of the chain. Check out Chuck's picture gallery, he has pics of the adaptor. Look in the thread below by darell to see pics of what the Honda connector looks like.
Good luck, hope this helps.
-SJ
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DEP '01 EX no-navi
