Polk Audio LSi15 Upgrades

Subwoofer upgrade using polk DB840 single coil 4 ohm subwoofer

The materials:

8 - 8 x 1 inch button head phillips screws.
Mortite (buy the small pack you will not need much)

DB840 replacement

First I removed the speaker grills I was able to pry it out with my finger nails. It wasn't easy. Be careful not to mess up your wood. Some people have a harder time than others.
I took the screws out and dropped the original subwoofer out. Get a box or something to hold it up so you don't put stress on the wires. You do not need to take note of which wire is positive and which is negative. Since the contacts are different sizes.

Remove the rubber seal from the new DB840 subwoofer. It looks like this and fits around it like a tire. If you do not remove this the driver will not likely fit all the way into the bottom groove and will not have much support if it sits on the top groove.

The DB840 without the rubber seal.

Lay the speaker down on its side on carpet or something so it won't be scratched. Put the dampening material all the way around the inside bottom groove of the cabinet hole. There are 2 steps or grooves. In my case it took 3 beads of Mortite. Also mark the Mortite where one of the screw holes is so you can line up the subwoofer. I just depressed it with my fingernail.

Place some cardboard or cloth over the speaker to protect the speaker in case you slip. Now attach the wires to the DB840 driver.

You should make sure the writing on the driver is facing up. Carefully align it with the screw hole you marked then drop it in. If its not right it will be difficult but you can push it around. Fasten the driver to the cabinet with the original screws you took out of the old driver. Some people are done here, if you stripped any of the screws then you will want to add more as I did.

Drill pilot holes in the remaining screw holes. Then screw in 4 additional 8x1 inch screws.

Here it is all done. Notice that it is not very good looking. You have the bare speaker metal where the surrounds are glued on and screw holes.

In addition the wood is not well finished on the inside.

So just place the grills back on the speaker. At some points you may remove the grill to show someone your modification or speakers, they could also rip or get ruined. In these cases you will be happy you lined up the driver so the words were upright. But for the most part I doubt anyone will see it if you forgot or it wasnt perfectly aligned.

All content copyright Rudy Sloup July 2013 till forever.