Has anybody actually done this mod, adding better insulation? How easy was it? It look to me like it might be hard to get the stuff in the lower part of the cabinet since you will have to reach in through the woofer hole in the middle, and also work around the bracing.
I have the same question. How significant are the gains?
I've modified my 360's which are the same as the 362 and 363. It was not easy. With the 250's it would be even harder because the driver hole is smaller.
I have layered the inside of a few speakers and subs with Peal & Seal and that isn't easy either.
The only thing that I A/B tested was the added insulation on the floor of the 360. I had insulation in the bottom of the right speaker but not the left for about a month. A handful of times I noticed a not so pleasant characteristic from the left speaker. Once I put the insulation on the left side the sound never returned. If you do this you may need to split the pieces of insulation for the floor in half so that they are shaped like bricks to get them in. Wrap the top layer with acoustically transparent cloth first. Thinking you are going to get in there later to glue cloth onto the insulation is a mistake. There isn't enough room for your hands in there, never mind room for your hands to work.
Tipping the 360 to angle the tweeter to the height of your ears is also a mistake. It wants to fall over as it is. It is better to raise the entire cabinet up on a 5 or 6 inch base. I would think having the inner and outer part of the base somehow decoupled would be good for something. You can get an idea of what I mean in
this post. Uhmm ... this wasn't easy either.
So the insulation on the bottom and raising the cabinet produce significant gains.
How significant? They now sound like speakers costing ten times more.
I also did what I could to silence the cans used for magnetic shielding. I had better luck using caulking than Super Glue. I did all those at the same time so I can't claim to have heard a difference but that is what I would say to do first. That gets your feet wet with dealing with the inside of the cabinet and is in fact relatively easy. One thing nobody has ever mentioned while flinging the word 'easy' around is what a pain it is dealing with the remounting the crossover on all this insulation. If this was easy girls would be doing it.
