The Big Fat Dots do work well when used under a stand or between shelves; the vibration is absorbed.
They will absorb vibration, but don't forget, the speaker itself is resonating and you don't want to stop that.
It might be possible that the Fat Dots affect the bass purity and detail by absorbing the speaker's vibration. But I doubt it, since the Dots are a porous material and not a solid, they should let sound pass through and not be absorbed. Besides, I trust Herbie, I say give them a try.
More importantly, you should isolate your NAD amp from causing vibration, (even a CDP causes vibration). The best way is to use Herbie's Tenderfeet or Big Tall Tenderfeet under the amp and other components. I use them under all of my components to great success.
They will absorb vibration, but don't forget, the speaker itself is resonating and you don't want to stop that.
It might be possible that the Fat Dots affect the bass purity and detail by absorbing the speaker's vibration. But I doubt it, since the Dots are a porous material and not a solid, they should let sound pass through and not be absorbed. Besides, I trust Herbie, I say give them a try.
More importantly, you should isolate your NAD amp from causing vibration, (even a CDP causes vibration). The best way is to use Herbie's Tenderfeet or Big Tall Tenderfeet under the amp and other components. I use them under all of my components to great success.