While I was ordering an Insight DAC, Frank Van Alstine said damping my speakers with PlastiClay would improve their sound. I had already opened my Von Schweikert VR2's to install additional cabinet bracing as documented
here, so adding more damping to the speaker baskets was easy. I used about 1/3 lbs. per speaker.

Frank first wrote about this tweak in the very first
Audio Basics newsletter, Volume One Number One, January 1982, which is still available on the AVA website, and it is still as valid today as it was 26 years ago.
The results were just as Frank described with the sound now clearer, less colored, quicker, and smoother. While playing with the clay I also noticed the housing around the magnet rang like a bell when struck, so I wrapped the housing with some left over
VB-2 vibration damping material.
This is a great, cheap way to spend an afternoon and you will be pleasantly surprised at the end of the day with how much clearer your speakers sound.
Wayne