Gregorx8, j'ai hâte que ton pote se penche sur le souci dont on a discuté au tel hier 
Peut être que cela peut aider, cela doit être le plan de la connectique du poste oem qui soit dit en passant semble être en bas niveau et pré-amplifié BOSE ou non:
http://www.rx8france.com/forum/viewtopi ... 0&start=20
Une fusion de tous les X posts sur la sono serait la bienvenue !
Sinon la solution est peut etre là mais il nous faudrait des traducteurs confirmés: http://www.rx8club.com/showthread.php?t=30579
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.
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
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)
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.
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.