Bobby Kinstle

As I mentioned in the other thread, I've replaced my sub. I did a lot of math and guesstimation and decided to follow "The possibly dangerous way" on my spreadsheet and drop a 4 Ohm DVC sub into the factory location and wire it up to the factory amp. I used the 10" Kicker CompC after doing a bunch of Thiele Small calculations. This woofer was the best calculated fit that also had an acceptable SPL rating. Pioneer makes some nice free air subs but the efficiency sucks. On my B8 I used a Pioneer Champion 10 but it was heeeeuuuugggggeee and really hung down into the trunk a lot. Installation wasn't too bad except for bending myself into a pretzel for an hour or so. I also used a 3/4" spacer ring to lift it up a bit. That still leaves a good half inch between the top of the surround and the bottom of the rear deck fabric.

Sound quality is excellent. Bass is DEEP down to 27Hz. It's tight and clear. You'll hear every detail. This plays only just barely louder than the original sub so if you want MORE bass or a booming system, you are going to need an amplifier. It'll get louder after a proper break in a month or so.

Procedure is basically the same as the B8 but with the rear speaker grilles.

Step 1:
Use a trim tool to pry out the D Pillar covers starting on the front edge. It has a long fabric tail in the very bottom rear by the glass that will be the last part to come out. Try not to rip it off. Both sides need to come out.



Step 2:
Use a trim tool to pry up the speaker grilles on the rear deck starting with the front edge and then lifting up at the front edge. Unplug the surround sound speakers and set the grilles aside.


Step 3:
Unscrew the four T25 Torx screws that fasten the deck fabric to the B&O subwoofer. If you don't have a right angle adapter for your screwdriver pause here, go to the hardware store and buy one. You'll need it again later.


Step 4:
Fold down the rear seats. The rear deck fabric bends down behind the seats. Put your fingers behind the fabric but in front of the metal and lift up. There are a row of snaps that hold it down. Just lift up and they will unsnap with moderate effort. Set the fabric aside in a clean place. Be careful the edges are sharp and they will cut you. Go ahead ask me how I know that.


Step 5:
Unscrew the factory sub which is held in by three T25 Torx screws. Did you get that right angle adapter yet? Unplug the power wire and lift the subwoofer out of the car. Place it next to your new sub and admire how sad it looks next to your new hotness.


Step 6:
Apply your favorite sound dampening material to the metal around the subwoofer. The frame is actually pretty well damped already but there are a couple areas that can use it. I also closed up the large rectangular hole next to the sub to help isolate the trunk cavity from the interior cavity for better sound. You'll also need to unclip one wire that runs in front of the old sub so you can move it out of the way for the new sub.


Step 7: Hopefully you located and drilled all the holes in the mounting spacer by now. Fit the spacer onto the woofer and then drop the woofer into place and find the best alignment. Carefully drill one mounting hole through the rear deck. From here you can just do all of them if you are careful not to damage the woofer, otherwise, remove the subwoofer, put one screw in that hole and then use the other holes in the spacer ring to locate the remaining holes. Even with the right angle adapter I was only able to get into the front 6 holes. Drop the woofer back in and screw in sheet metal screws appropriate for the holes you drilled.


Step 8:
Connect the new sub to the factory wiring harness. I need to get back in there and write down the wiring order, but the long answer is, the inner two wires on the plug are Coil A and the outer two wires on the plug are Coil B. If you don't want to cut the harness you can sand down some 3mm spade lugs and just stuff them in to the plug and secure it with some hot glue. If one coil is wired backwards, the woofer won't move at all because they are pushing against each other. If the woofer plays but the bass is very weak, then it's wired out of phase to the rest of the car. Reverse the polarity of BOTH coils. If you are using your own amp, you can connect it now.


Step 9:
Put everything back in the reverse order of above. Make sure that you get all the snaps on the rear deck secured back down or it'll rattle. Go into the trunk with a file and blunt the points of the screws that are holding the new woofer. If you are using a different woofer or spacer make sure you check that there is space between the woofer surround and the fabric before snapping the grill back down. I was able to fit a finger between them which is plenty.


It came from outer bass


The kicker CompC hardly takes up any trunk space at all.

Bobby Kinstle

Now that I've gone a little deeper down the rabbit hole, I wanted to add that you can substantially improve the bass in the car by replacing the front door woofer with a good 6.5" woofer. I just turned my sub down a lot after doing this myself.

BTW The front door woofer is probably the most difficult to replace speaker in the entire car.

Sforfun

Great work, looks excellent. Is there enough room under the deck for the excursion on the sub? It looks awful close to it in the pic.

Bobby Kinstle

Thanks! It does look closer than it actually is. I can put my fingers between the top of the surround and the bottom of the deck, so I'd say about 5/8" of clearance, which is plenty. I tried to photograph that but it always looked flat in the photos on my cell phone camera and I was far too lazy to get my SLR and shoot one handed. I have a 3/4" spacer under the woofer too, so if you need more XMax, you could use a thinner spacer too. I was trying to limit the amount the magnet hangs down into the trunk.

BTW I decided to add an amplifier. The factory amp is plenty powerful driving a 4 ohm DVC sub, but since I also replaced the front door woofers the new ones were playing down to 45Hz and I'm getting some strong overlap. It's not a huge problem, but I want to boost the really deep bass up higher and it's way too hard to high pass the front door woofer. I could solve all these problems with a few keystrokes if I could get access to the B&O amp programming interface, but that seems about as likely as catching a meteor in my teeth while riding a great white shark down a lightning bolt. If you don't replace the front door woofer, then it really isn't a problem.

One last word, try to buy a woofer with a high SPL rating. The factory sub was efficient, like around 90dB, If you plan on using the factory amp I'd say your replacement woofer should be at least 87dB, but higher if you can.

*EDIT: I was able to measure the SPL of the factory 10" woofer finally and it's 87dB.

SHCKR

Bobby, where are you located? Could definitely use some one on one coaching based on your experience and expertise.

Bobby Kinstle

I live in Livermore CA, and work in Fremont CA. If that's too far away you can just shoot me a message.

BTW I'm nearly done with adding the subwoofer amp in the trunk under the spare tire. I had some health issues that caused me to put it aside for about a month or so, but now I'm nearly done and should have it up and running by the weekend.

SHCKR

I'm on the east coast, but I will gladly accept any help when I actually get to fixing the overly expensive B&O package. I had a kicker L7 in my last vehicle (I know, old) but I was really impressed with performance, paired with a 1200 watt amp.

Bobby Kinstle

Oh wow, those L7's can really pound. Are you looking to just do the subwoofer or get a bit deeper? Have you seen my ongoing guide to the B&O system? The factory sub opening works with many 10" round subs with a 3/4" MDF spacer if you don't want a trunk box. Lots of things will rattle back there if you go to L7 levels of bass so plan on doing some dynamat at the same time.

https://docs.google.com/spreadsheets...it?usp=sharing

The factory amp can drive a DVC 4 ohm sub OK, and I'm not really sure about the power level but probably not more than 200W. You can connect an amp to the speaker level outputs of course, but bear in mind that those outputs could go as high as 26V since the factory sub is 8 Ohm DVC, so you should either select an amp with a high input voltage rating (Many kicker amps can go to 40V) or you might need a line converter. The Pioneer amp I'm installing can accept up to 16.5V input which should be fine for me since I have no intention of ever turning the volume up that high.

markjohnsonii

@Bobby Kinstle did you look at the Pioneer TS-SW2002D2 8" 600W Shallow Subwoofer w/ Dual 2" VC? This wired in series instead of parallel should achieve the needed impedance; it won't have separate power feeds to the "DVC" in that config but that shouldn't matter in this application right? It's much smaller and has a better frequency range than the Kicker CWCD104 CompC 10" does at 2" less inches. I think that's interesting.

Specs:
-Size8"
-Max. Music Power (Nominal): 600 W (150 W)
-Frequency Response: 20 Hz to 200 Hz
-Sensitivity (IN CAR, INPUT: 1W): 86 dB
-Impedance: Dual 2 Ohms

$72.99 @ Walmart. Pioneer TS-SW2002D2 8" 600W Shallow Subwoofer with Dual 2" Voice Coils


Pioneer TS-SW2002D2 8" Sub front



Pioneer TS-SW2002D2 8" Sub Back

Bobby Kinstle

You won't have enough power with just one sub channel wired up.

Usually the shallow subs struggle to get much below 35hz, especially in free air.