jtwrace,
What is your personal experience upon which you base "this (Acoust-X Sound Damping Coating) does work well when properly applied"? Does it cure hard like a bed liner or softer so it can provide some limp mass damping effect?
Visiting the link I find no real details or measurements. Disappointing, for a manufacturer it is not that expensive to run tests with accelerometer data. There is one review that is for a PA speaker application. They do reiterate applying in a thick coat and then a second coat "if needed". Reading between the lines with my engineer's skeptic hat on if evaluating it I would expect to apply two thick coats to obtain some effect.
If Acoust-X Sound Damping Coating cures hard my experience is that is producing a simple mass loading effect and such avenues yield disappointing results in the context of high-end HiFi speakers. Its the compliance + mass in products like GR's No Rez and 3M's Damping Foil 2552 that achieve wider range panel damping.
