Micro Bearing Steel Fill...I bet that can be purchased locally. Lak, I told you yesterday the effecs placing the Goldmund cones had on my transformer based Clear Image T4 filter. All the music improved substantially, especially at higher volumes. The wire that vibrates the most is the speaker's. I have touched it while playing and it vibrates heavily. I had been contemplating the idea since I started playing around w/ my t4, but it only makes more sense as time goes on. Making my own speaker wires w/ fill...