This is a fairly long guide so bare with me.

Whats the problem:

The stock RX8 hifi is a reasonable attempt at in car hifi but not as good as it could have been. The main issues are that there is very little definition with the high frequencies and the sub bass is very muddy indeed.
To liven up the low end we often turn up the bass on the head unit but this has the added effect of turning up the mid bass as well which makes the whole thing sound very boomy rather than tight.
To liven up the top end we often turn up the trebel on the head unit but this has the added effect of upping the upper midrange which makes the whole thing sound very crashy.

What are the reasons:

Compromise mainly. The 2 drivers in the doors are a 9" woofer and a 2" tweeter. This is not ideal as the 9" woofer does not have the dynamic range to accurately reproduce the midrange sounds. This means that the crossover between the woofer and the tweeter is a lot lower than you would expect (about 1kHz). The 2" tweeter has to do a lot of the midrange work which means it's sensitivity drops off massively at the very high frequencies (14kHz+).

Solution:

Add some extra tweeters to handle the very high frequencies while retaining the stock tweeters to reproduce the midrange.
Add an amplified subwoofer so we can independantly control how much sub bass we want. This has the added bonus that we can lower the bass control on the head unit and remove some of the boomyness from the upper bass frequencies.

You will need the following kit: 1 x subwoofer in a sealed enclosure, 1 x amplifier, 2 x tweeters, 5M 8 gague power cable, a lot of speaker wire, soldering iron, patience.

Subwoofer install:



I went with a Kicker 10" sub and a Rockford Fosgate Punch Power 100W amplifier mainly because I've had them kicking around for a few years (By the way, you will need an amp with speaker level inputs). 100W doesn't sound like a lot but when it's bridged in to a single 4 ohm load it produces nearly 200W.
I also purchaced some Kenwood tweeters for £45 from a local hifi shop.

The first thing you need to do is run the power cable from the front of the car to the back. The difficult bit is deciding how to route it through the firewall but I found a nice easy place.

Looking at the car from the front with the hood open, look to the left of the firewall. You will see where the hood release cable exits in to the engine bay. Thats where we are going to run the power. Jam a screwdriver inside the grommet to widen it and shove the power cable through (see below). It will enter the passenger cabin just above the throttle pedal so make sure when you finish up, you cable tie it out of the way.



Once you have it pulled through (with a little left in the engine bay to connect to the battery) we need to route it down the car to the inside of the boot. The panel that runs the length of the door opening comes off very easily. Just grab it from the inside and pull. Underneath are some really nice cable tidies that we can make use of. Push the cable through all 3 of them untill you have it tidy and the end resting on the back seat (see below).



Move to the boot. On the right hand side of the boot is a carpeted panel. Remove all the popper studs (6 of them) and take the panel out. We need to remove this as all our wiring is going to hide behind it.
Next thing to do is remove the bottom section of the rear seat. It's only clipped in place so just grab the front edge of it and pull up sharply. Once the seat is out, pull the side bolster away from the drivers side of the car and stuff your power cable up inside (see below)

 

You should see it come out inside the boot near where you removed the paneling (see below)



OK, power is now sorted for the amp. Now we need a ground.

On the right of the boot you should see a hole. This is a good candidate for a new ground. Scape the paint off around the hole and then affix your ground wire to the now clean hole with a nice steel bolt (see below)



Next problems are to get a remote turn on for the amp and some speaker level inputs.
For the inputs I just took a tap from the two 6"x9" rear speakes using scotchlock.
For the remote turn on I stuck a multimeter in all the connections on the amp blue connector to try to find a 12v supply that was switched with the ignition or stereo switch on. I found one. It is the pink and black wire on the top endge of the connector. Disconnect the connector and scotchlock a wire off it (see below)


(I got the wrong wire first try so the image is somewhat missleading)

Connect your subwoofer to your amp, the amp to power, inputs, ground etc. and we are done in the boot.

Next job is to get power to our amp. Move back to the engine bay. Add an inline fuse to the power cable (see below) and then connect to the battery. A fuse slightly larger than the fuse that is in the amplifier is what I would recommend. Make sure there are no shorts and turn on the hifi



Button everything back together and tidy up.

You are now done with the subwoofer.

 

Tweeter install:

Wind down both front windows. The triangular panel that holds the stock tweeter is just a snap fit. Grab the edge nearsest to the wound down window and pull sharply. It will come off (see below).



Disconnect the stock tweeter from it's wiring. You will see a foam covered connector. Squeeze it and pull the wires to undo.

Take your panel and your new tweeter to the bench and heat up your soldering iron.
We need to solder the extra tweeter on to the original one AFTER THE FILTER CAPACITOR (see below)



Once you have done both, reattach the connectors and snap the panels back in to place and find a nice place to mount your tweeters. You are now done.

Play with the bass and trebel controls as well as the gain on your new amp until you are happy with the sound.







Sum up:

The difference in sound quality is just stunning. The bass is now very tight at the bottem end and you can actually hear the high frequencies. It's now what I would describe as "well balenced".

Total outlay:

Amp - £150
Sub - £100
Box - £50
Wire - £30
Connectors - £30
Tweeters - £45

Total = £405 which in my opinion is a bargain for the sound quality I have achieved.

Total install time = About 3 hours depending on experience.

I will probably replace the amp and sub with something a bit beefier when funds allow. Probably a Kicker Solabaric and maybe a Phoenix Gold amp.

 

Excellent explanation and pictures. You made it look so easy that even a novice could give it a whirl.

I'm with the crowd that doesn't like the extra tweeters sticking out like a lump on a log, but that's just me.

At first I was frustrated with the sound quality of the Bose, but I have to admit I've gotten used to it - like the person with a fuzzy television picture who gets used to it because he don't know any better after a while.

 

Tweeters are directional and ideally should be angled so that the sound waves cross in the middle of the car cabin at about ear height of the front seat passengers. The way the BOSE tweeters are mounted you would need to have you face pressed against the windshield to get the optimum stereo image!

I agree that it may not look that pretty with additional tweeters mounted over the plastic panel but I bet it sounds a lot better.

 

if you face has to be pressed against the windsheild, what is the likelyhood of the bose system using the glass as a reflective point, to make the sound apear as though it's coming from in front of you, rather that from the side? just a thought :-)

when we designed my old subwoofer enclosure in my first RX-7 we wanted to see how much we could crank out of the equipment that i had.

we built a ported box that aimed the woofers parallel to the hatch glass. i registered something near 149DB with that system. i know SQ isn't the same as SPL but i do know that glass can be made to play an integral role in automotive accoustical engineering.

Ray

 

How great does this sound. But the only problem with SoloBarics is the corners bust out of them over time. Ive had a few audio dealers tell me that.

 

KEnwood makes a nice tweeter i am installing tommorw .. Ill take pics .

 

Awesome install, this is a great DIY.

 

Thanks for the comments guys.

It sounds really rather good for a quick and dirty setup. I do know what I'm doing with hifi by the way so it did pain me to have to do it like this which is kind of a bodge really. Well, it works and sounds good so I'm not complaining.

Maybe one day I'll pull the whole system out and do a proper install.

Remember for you US folks, everything should be reversed. I did this on a UK RHD car.

 

Agreed, this is a great DIY! I'm moving it to the DIY forum. :D What a nice contribution, expecially for a new forum member. Well done, rilot!

 

just one question about the sub install , what kind of scotch lock did you use ? and should I connect before or after the bose amp ? (sorry , if it sounds like a studid question , I am a novice at car audio)

 

I have a question as well. If you use the wires going to the stock 6 X 9's as your subwoofer amp feed, do you disconnect the 6 X 9's? I remeber trying this once and the 6 X 9's acted like a microphone when the wires connecting to them were also used as amp inputs.

 

Does anyone have the pictures of this procedure? I would like to do my subs using this process but is this DIY still recommended? its kinda old lol... I have two 10inch pioneers and sum gay amp but it was all given to me for free. Also what is scotchlock? is that some English European term for tape?

Also a question about my amp on one side theres a dial for x-over which goes from 50 to 500 what is this? Thanks to anyone that has further knowledge in this field

 

bump

 

anyone got updated pics on this one?

 

nice seems pretty good

 

wished those pictures still worked!

 

bump. somebody sticky this ****.

 

WOW! What a difference, all i installed the first day was the tweeters. Next day i upgraded the rear 6x9's. The tweeters alone made all the difference in the world. The subs are coming in a couple of weeks, I'm planning on a pair of 10 in Memphis subs in a box against the rear seats so I can retain my spare tire. Does anyone have pics of there tweeter placement? I ended up just putting them next to the factory ones for now. Let me know what you think.

 

i don't know. would have to see photos in the car man.

 

i would be perfectly happy with this solution, the holes for the tweeters look as if they were conformed to the speaker, almost factory looking. please tell me how you installed the new tweeters? i dont mind if they aren't mounted in optimal tweeter position, figure it will make the sound better anyways. thanks!

 

If your using the factory deck, do you have to use some kind of high frequency converter?

 

Alupis- All i used was some Ace Hardware 2 part plastic weld epoxy. I drilled the holes a little small, then match fit them with my x-acto knife, then mixed the epoxy and lathered it on.

Hiro- no, putting the tweeter after the the converter on the factory tweeter lets the factory component do most of the work. your new set of tweeters will also have a frequency converter that will clean the rest of the signal up.

Sorry for such a delay on the response, i've been away from the computer awhile.