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I've searched the forums these last two days, but haven't found anything that specifically addresses my situation:

If I put a Special Edition HU into a 2004 Civic EX sedan and then want to add two tweeters (like in the 2005 Special Edition Civic, from which the HU came), how would I go about wiring them in? Is there some sort of special wiring done in the 2005 SE or did they just run off of the wiring for the front speakers?

Now, as I said, I didn't find anything specific in my forum search. However, I did find two things that might help:

1. I can get the tweeters really cheap over at Honda Automotive Parts and they look to be the same as what's in the 2005 Special Edition Civic. That means that all I'd have to do is drill the door holes and wire them up ("all I'd have to do..." Right, like it's soooo easy).

2. I found this post from CplJon and it got me to thinking: if all I want to do is add the two tweeters and I use the OEM ones, then I should be able to wire them in without overpowering the HU or having them sound like crap, right?

I'm not interested in getting another aftermarket HU. I just got rid of my Alpine CDA-9856 and really want the Special Edition HU. Besides, I got it for a really good deal of $200, so I couldn't pass it up. I mean, seriously, I went the route of the "Gotta get the Alpine! ALPINE ROCKS!" road and it didn't work out. I don't need all that power or options, so this Special Edition HU will do me just fine.

I simply need to know if the 2005 SE Civic has a special wiring harness for that six speaker setup or is this a scenario where I can simply wire it into my 2004 EX Civic with its existing harness. Any and all opinions are welcomed, because I desperately need to find an answer.

Thanks, all!

 
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i am pretty sure they tap the tweeters off the deck front speakers, but this is not the proper way to do it. it slightly messes up the ohm load and you dont want that. if you want tweeters, i would suggest getting a very low wattage amp for the four main speakers and then just run the tweeters off deck power.

 
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Stupid question: Why? What does it do?

Any recommendations?

 
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^ it burns out you HU. get a cheap alpine, check ebay for a cheap one in $100 range. i have had the mrp f240 which is around 30wrms per channel (4 channel amp) and its been going strong for 4 yrs. only paid $200 when it first came out.

 
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I just want to make sure I'm following you: Honda ran the tweeters off of the front speakers, but that's bad, because it could burn out your HU? If that's the case, then why did Honda allow it to be done like that?

 
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In the EX Coupe or special edition setups with component speakers there is a capacitor on the tweeter acting as a 6db/octave crossover and the larger speaker in the door can't produce very high frequencies. The EX Sedan doesn't have tweeters in the sails. The question comes down to what kind of speakers you have in your door. I have seen factory coaxials in these cars as well as factory mids.

When speakers are wired in parallel (or series) there is a change in impedance in the network much as there would be with two resistors.

(Series) Req = R1 + R2 + R3 + ...
(Parallel) 1/Req = 1/R1 + 1/R2 + 1/R3 + ...

The reason Honda gets away with it is because impedance is frequency dependent. So, the frequencies being ably reproduced by the tweeter are separate from the mid because of the mid and the cap on the tweeter. The issue with your setup could be the impedance over the frequency range of the tweeter would be lower than that which the amplifier in the deck is designed to handle. The reason is because of the equation i=e/r. (Ohm's Law, current = voltage / resistance).

If we take a look @ the parallel resistor equation from above we saw two 4 ohm speakers in parallel is equivalent to a 2 ohm load. Let's assume e=10 for no reason whatsoever
r = 4 ohm
i = 10V / 4 ohm = 2.5 A

if r = 2 ohm
i = 10V / 2 ohm = 5 A

The specific voltage numbers we've used aren't important so much as the general idea that a decrease in resistance results in an increase in current. The amplifier is designed with a minimum impedance and using a lower one will pull more current thru the amp over time. Basically, the amp is run hotter than it can handle and it will wreck it.

So, if you were to wire the Honda tweeter in parallel to your existing door speaker the impedance could be too low for the high frequency range. I doubt it would wreck your deck right away but over time you'll notice your deck getting real hot and it will most likely fail prematurely.

Now, if you use a cap as a crossover on the tweeter and the mids in your door aren't coaxial you'll be okay. The setup gearbox calls out will be a much better way to do it but then again there are many better setups out there, it's all about what you want to spend. You may also want to look at getting those sail panels from the EX coupe, they will make for an easy and quality install. Basically, when you pull your door off you'll see what kind of speaker you have (my experience leads to believe coax) and then you'll know. I included the wiring doc for an EX coupe so you can see how Honda does it. Sorry if this was all over the place and I hope you find this useful and sorry for hijacking.

 
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wow good explanation!

 
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^Agreed! Very detailed explanation. It'll take me a few to digest it all, but now I have a better understanding. Thanks, christmaspie!

I think I'll do some more research on exactly how Honda did it for the 2005 SE Civic. If I don't have any luck, then I'll probably go with gearbox and his idea...