Something tells me the difference was made in setting the low pass filter properly. The polyfil might make a slight tonal difference, but probably barely noticeable. Especially since he only used 1/2 pound.

 

Actually, I had the amp settings at what they are now for approximately a week before i added poly fill and it still sounded terrible. But after adding polyfill the improvement was immediately noticeable. 1/2 a pound doesn't sound like a lot but since it weighs almost nothing,but it was enough to fill my ENTIRE type r zenclosure box .75 ft'3.
Those who don't believe it's benefits, here are two links explaining in detail what fiber/poly fill does to your sub in the box and how it affects the sound.
But like all things it may be more of less noticeable depending on the person but it made a big difference to me. and i have no reason to lie http://www.soundsolutionsaudio.com/f...showtopic=7168

http://www.sounddomain.com/ubbthread...rue#Post551110

 

I fully understand the physics behind what it does. And have been lining the inside of enclosures with the stuff for nearly 15 years. The polyfil alone I have a hard time believing made that much of a difference. Could it be perhaps that before the polyfil you didn't have a good seal and were leaking air from around the sub, and then when you removed the sub to fill the enclosure, you tightened the sub down and completed the airtight seal, thereby making a VAST improvement in the sound?

But I've seen stranger things and since I wasn't there I have to take your word for it. The bottom line is it's all better now