Amplifier Enclosure Resonance

I used 2 Walker resonance control discs on the unperforated strip down the center of my Ref 150. It damped the vibrations exactly as ordered.
Last year, I elevated the amps well off of the floor and removed the top enclosure to get better ventilation. But if the top must stay on--I highly recommend the discs which fit well and work well. 

Hi imgoodwithtools:
 I did not notice any difference in sound between top off or top damped with the Walker discs but, in all honesty, I did not conduct a careful before and after analysis. My gut tells me it might be slightly better with the top off, although with the top damped by discs there were no longer any top vibrations that I could feel. My feeling is that if you have no pets or children to worry about and the significant other does not mind---off is the way to go for reasons of both vibration and ventilation. If all 3 conditions are not present, the top with discs is the way to go.