November 14, 2014

G-Wagon Tunes!

Early G-Wagons suffer from a lot of cabin noise so getting a good music experience is really difficult. The first step is to reduce cabin noise (see other posts), the second is to get a good stereo that will overcome the noise and provide good balanced sound. 

My brother Paul and I used to run a couple of high-end stereo stores in Atlanta so I've got a little experience with car sound. The first thing you need to know is, unlike cars made before 2000, most modern cars have really good sound systems. The second thing is getting good sound into older cars does not have to be expensive if you do a little DIY. The final and most important thing is to make sure you design the system for the interior of the car and what it needs to do when the car is running. That means listening to speakers in a showroom may not be the best idea.

For any car, the system should be more bass forward than a home system to have a good experience in a running car. That is because the rumble from the engine and road noise provides a lot of low frequency interference. Your ears will start to ignore that sound so your stereo will need to be able to overcome that low end noise and make up the natural attenuation of your ears. Listen to any car system with the engine off then go for a drive and you will see what I'm talking about. 

From the factory, the early W460 has the ability to support 4x6 speakers. Two in the rear pillar and two in the kick panels up front. Frankly, I don't believe 4x6 speakers will cut it. A previous owner had installed 4" speakers in the lower part of the dash on each side, not unlike what Mercedes was doing to just about every car in the 80's.

After pulling all the interior out of the car I decided that the rear pillars could take a 6.5" component speaker system, and I could add two more 6" dedicated woofers in the front kick panels. I decided to change the head unit to support Bluetooth music, had an output for a subwoofer and kept with the German theme. That meant Blaupunkt, although you can choose any single DIN stereo. Another G-option are head units from VDO.


The rear pillars were very easy to put the 6.5" component system. Since I was recovering the interior, I simply cut the holes making sure to have enough clearance then cover with MBTex. The thing about the rear pillars for speakers, is that the cavity behind the speakers rings like a tin can. Without deadening the metal and putting in some sound treatment, any speaker would not produce that solid bass or clear midrange needed for good sound. Do you have a W460 handy? Go back and knock on the outside next to your rear door. Hear that ring? It needs to GO or your stereo will not thump!

Like the doors and roof, I covered the entire rear pillar exterior metal with Dynamat and Dynaliner. I also stuffed it with Fiberglass prior to installing the panel. After applying the treatment, the enclosure was solid and as dead as any quality speaker cabinet. 
Rear Pillar Stereo Speakers

Then I mounted the component speaker system in the rear pillar area making sure to place the tweeter high enough to clear the back seat. For the rear speakers I selected the Kenwood KFC-P709PS 6.5-Inch Performance Series Component Speaker System for about $60. The woofer of this system is not very deep and that is important because there is not much clearance there. Mounting the speaker lower provides better clearance, but even then I needed a spacer ring to make it work. For that extra finished look, I painted the grill of the woofers to match the trim of the car. 

I put an inline capacitor in the existing Kicker front speakers to keep the bass that the speakers could not reproduce anyway from overloading the speakers. With a 4 ohm speaker, I decided to use a 200uF 100V Non-Polarized Capacitor that would roll off at about 3db per octave starting just under 200 HZ. Not only would the reduction of bass signal going to the speakers allow them to play louder without breaking up, it would eliminate any potential low frequency phase issues with the near by woofers installed in the kick panels. 


Subwoofer in Front Kick Pannel
Then I got a couple of $50 6" woofers and installed them in the kick panels. That required some cutting into the metal behind the kick panel. Cutting the thick steel ended up being the hardest part of the entire job. No wonder these cars are so heavy. Additional sound deadening treatment was installed behind the kick panels.

I installed a $40 Pyle PLMRA120 2-Channel amplifier on the back of the dash just under the glove compartment. I took the subwoofer output from the head unit, split it with a Y connector and sent it to both channels to the amp. I routed the amplifier power from a new constant 12V fuse box installed behind the glove box and the trigger power from the head unit. 

I chose to use the Blaupunkt Toronto 420 BT head unit as it had plenty of power to drive the front and rear speakers, two USB ports with iPod support, CD player, and Bluetooth all for less than $150. I installed to to the existing wiring including a trigger for the dash lights so the Blaupunkt would dim at night.

After it was all done, It took a while to tune the parametric EQ and subwoofer output but once adjusted the final system plays nice and loud, has clear highs and nice bass. Most of all, it looks pretty nice.

Most folks really don't care about a nice stereo on an older G-Wagon but this is my winter daily driver, and I needed my tunes. The bonus was that only $300 the entire system came in well under my $500 budget. 

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