I have 2 of the 9 1/2" x 4 1/2" plates; one atop my Marantz RS15SA SACD player, and one on my CJ MF2250 power amp. You can notice a difference in imaging and the plates tighten up the bass considerably. In terms of A/B comparisions; it requires a very good ear and very little delay between samples. Use for test material bass laden tracks with already good imaging and localization. You can feel the difference the HRS plates make as well by resting a light finger atop a component while the music is playing, do it first with then without the plate and you'll notice a significant difference. It logically follows that this reduced external vibration would translate into better sound. Solid State components with heavy chassis and no moving internal parts show little improvement, but any CD player or transport will benefit from a HRS plate placed above the disc mechanism. The smallest plate is adequate for this application. I've seen components completely covered by these plates as they are sized to accommodate this (usually 3 of the biggest 14" plates will cover an entire component). I haven't tried this myself, but I would rather do that then spend money on bases, feet, and discs because the improvement is a known entity, and I feel that the other options are more subjective with varying results.
