My Sony sub & polyfil (from Walmart for $2.xx) ready for action. (You should be able to get polyfil at any craft/hobby store or fabric stores for sure. Polyfil is commonly used in quilting so a fabric store will definitely have it.) I first unplugged the sub and disconnected the audio cable. Then I laid the sub gently down on its back. I removed the grill by pulling it off gently & then unscrewed the 8 screws holding the driver in place.

 

Before Photo: Pre-modded sub - driver removed & looking down into inside of sub (the top of the sub is at the top of the picture, the bottom of the sub as at the bottom of the picture) Be careful removing the driver - there are some delicate wires holding it in place.

 

Me breaking apart the polyfil (it comes apart pretty easily)

 

Finished product - I basically just stuffed the polyfil to the left and right sides, top, and back, leaving some space for the back of the driver. I left the bottom of the sub (where the port is) without polyfil. I then replaced the driver, screwed the screws back in & plugged it back in & was back in business.

Update (04/22/03): After having several people email me, I realized I hadn't really talked about the sound quality of the sub after I did the mod. Granted, I didn't have the sub that long before I did the mod, but the big thing I noticed was that the bass sounded much tighter after I did the mod. Instead of a vague boominess which it sounded like before, the bass definitely sounded more defined with the polyfil inside. And having had the sub for over a year now, I can say it's definitely been broken in and sounds better than ever. I can't say there is a massive difference with the polyfil, but in my opinion, it is definitely noticeable. Better? In my opinion, YES. Dramatically better? IMO, not really, but for $5 and some change and a few minutes of your time, definitely worth it.

For as cheap as you can get polyfil and as easy it is to do the mod, I would try it out yourself and see what you think. After all, we all hear differently and what sounds good to me might not sound good to you. Or perhaps you will notice a drastically better change than I did. If I'm feeling particular bored one day, I may pull the polyfil out and do some comparisons. But I recommend you do it for yourself and see what you think.