I upgraded the sub in my B8 Sedan with the symphony sound system.

I replaced the original sub by a Pioneer TS-SW841D shallow 8" and I installed a Sony XMS-1S amp.

The Sony XMS-1S amp is "auto turn-on", accepts a high level input and is a perfect fit on the flap door of the driver's side of the trunk. There is also a ground post nearby and I could pass the positive cable to the battery very easily through openings underneath the plastic trims.

The speaker was another story, a real mess ! I think that the size of the speaker opening in the back shelf of the B8 is smaller than on the B7. The Pioneer TS-SW841D shallow 8" did fit very well according to someone else write up who used it for replacing a Bose sub on his B7, but on the B8, the speaker is too big to fit in the original mount where the sub was installed upside down. The Pioneer is also too small to fit without the mount. It would falls through the opening on the back shelf...

I had to cut the original sub with a dremmel in order to use its basket screwed and glued to the original mount and to carefully drill holes to mount the Pioneer. Even then, it was not easy, because the screw holes would line up with the space in between the original mount and the basket of the old sub. The speaker was too big for the original mount, too small for being mounted without the mount and finally too small for the screw holes to line up properly with the original mount ! I had to use the provided large "wood" screws to fix the speaker to my now modified speaker mount and use silicone glue.

I think that the best way to mount this sub would be to make a ring that would have the inside diameter of the cone of the speaker where the speaker could be screwed to and an outside diameter slightly larger than the opening of the rear shelf where the original sub was mounted and to screw this ring from inside the trunk. This ring would have an inside diameter of 7.25 inches and an outside diameter of 10.25 inches.

I have also put some foam underneath the back self trim (in sandwich between the trim and the metal self that had been covered with Dynamat Extreme) in order to minimize any vibrations.

The sound is good and does not distort and the back shelf does not vibrate. This is the advantage of keeping the original mount; it keeps the self supported and sturdy. Some people just throws in a 10 inch sub in the hole, but they cannot retain the mount that kept the trim of the shelf from vibrating and they lose a lot more trunk space.

Total cost:

1. Raptor power cable ISPKBL4-4CH: 1 @ $19.99
2. Sony XM-1S: 1 @ $139.99
3. Pioneer TS-SW841D: 1 @ $84.99
4. Dynamat Xtreme Wedge Pak 10425: 2 @ $19.99
5. Dynamat 10007 Rubber Roller for Dynamat: 1 @ $17.99


Item total: $302.94
Shipping fee: $42.85
Canadian Brokerage, Duties and Taxes: $50.21

Total paid: $396.00 Canadian

 

More pictures

 

For those who might be interested in doing a similar upgrade, here is the polarity of the original non B&O B8 sub:

 

Bravo! Bien fait!

That is a very clever solution to mounting the driver in the vehicle specific OEM location. Thanks for sharing the pictures.

 

Hello, very nicely done!! I imagine doing the same thing, but do you think the original amp will hold to power the subwoofer?

 

I think that if want to have good bass and good control on the amount of it, you need to add an external amp.

The amp was not very expensive...

Sony XM-1S: 1 @ $139.99

 

Ok Just ordered the speaker/sub. I will try with the orginal amp first, and if the result is bad i will install the amp you recommend.

 

How do you connect the Sony XM-1S amp. and the speaker to the orginal system?

 

I installed the speaker, but the sound from it is very low, do you know if there is a way to control it?

 

There are a Level, low boost and low pass filter potentiometers for adjustment.

Make sure the low pass filter is not set too low or it will prevent the signal getting into the amplifier. Set the LPF to 300Hz (fully clockwise) for starters and adjust the level and low boost until you have the amount of bass you like, if you have to much overlap in the mid low frequencies with the other speakers of the car, then adjust the LPF in order to reduce the overlap.