Before anyone asks, pictures will follow shortly!
I'll describe what I've done.
I got a set of Jehnert (
www.jehnert.de) doorpanels and speakers to replace the stock dashmounted speakers. The doorpanels replace the stock lower plastic storage parts on the front doors. Each one has two 16cm midbass woofers in them. Before they were fitted I had the inside doorpanels sound deadened with spray-on sound deadening material. The Jehnert doorpanels are screwed down so the result is very sturdy with no annoying resonances.
The Jehnert dashboard speakers consist of 10cm midranges and separate tweeters. The midranges go where the stock speakers were and I put the tweeters on top of the grilles of the midranges. With a Dremel a hole was made so the tweeters are sunk a little in the grille and they were fixed in place with some sealant. Doesn't look bad at all.
The Jehnert speakers come with a 3-way passive crossover but I decided to go partly active. I have a 5-channel amplifier, a Xetec 5G-900 (
www.xetec.de), chosen because it has high power output but small dimnesions.
The front channels (100W each) power the dash speakers through the Jehnert passive crossover.
The rear channels (100W each) power the midbass woofers in the door and are actively lo-pass and hi-pass by the crossover in the amplifier.
The dedicated subwoofer channel powers the sub with some 450W.
This JL Audio 15W6 subwoofer (wired to 3 Ohm) was fitted in the spare tire well. I used the trunk carpet as a pattern for three MDF floor panels, all of them 50mm thick. One acts as the baffle for the subwoofer and fits on top of the spare tire well. The other panel is fitted left of the baffle and the last one is fitted right of the baffle on top of the battery cover. I did this to create a whole flat floor again. I removed the rear speakers so the sound from the subwoofer can get into the passenger area.
All these panels are carpeted in grey material to match the stock trunk carpet as close as possible.
The baffle was screwed down in the metal with some eggshellfoam acting as a seal all around. Before this was fitted the spare tire well was sound dampened with Dynamat.
The plastic carpeted piece that normally sits against the fuel tank was used as a pattern for a 6mm MDF panel that holds the amplifier and the 1 Farad capacitor next to it. The MDF panel was cutout in such a way that it would fit the same way as the stock plastic carpeted piece. This gave it already some sturdiness and a small L-bracket was fitted against the underside of the rear shelf to permanently fix it in place. All wiring for the amplifier goes behind this panel. I am going to have a perspex panel made to protect the amplifier and the capacitor in case I have luggage in the trunk.
Power wiring was very easy because the battery is in the trunk. I used a 100A magnetic circuit breaker as protection and from there a 4 gauge positive wire goes to the capacitor and from there to the amplifier. Ground for the amplifier goes from the rear shelf to the capacitor to the amplfier.
I had a Crystal Line line-driver lying around so I used that to boost the output of the Alpine INA-033R DIN sized DVD navigation headunit to some 10 Volts. This enabled me to set the gains on the amplifier to their lowest settings to avoid hiss. A single signal cable runs from the line driver to the amplifier.
The Xetec amplifier comes with a remote subwoofer level control and that was fitted in the center console.
It is a very tight sounding system. I think 90% of the people would be satisfied with the bass ouptut of the doorpanel speakers alone, they are very, very good.
As a former IASCA competitor I am quite pleased with the result. Staging and imaging is far from perfect but that was to be expected with dashmounted speakers so close to the driver but tonal quality is very good. The amplifier has more than enough power for the speakers and there is no distortion, even at very high levels.
I recommend anyone who is thinking about a stereo upgrade in their W124 to look at these Jehnert speakers and door panels. They are not inexpensive but well worth the money IMHO.
If anyone has questions feel free to ask.
Flavio