Any vibration from the waffling of the cabinet is unwanted, IMHO, but that reflects a design philosophy where the cabinet is not intended to color the sound.
Speakers that are built like tanks (heavy damped walls and heavily braced) are less dependent on this aspect - blu tack seems to be the optimum stuff to avoid wobbles and deaden any induced vibration.
If you use a lightweight cabinet such as a Harbeth and many consumer designs then of course you do need to worry as the cabinet itself is an integral part of the sound - so any modifcation as to how it "breathes" or "waffles" will alter the sound...this is why stereophile measures cabint responses with an accelerometer to see what unwanted resonances the structure exhibits.
Personally, I use multiple layers of MDF and rubber pads below my speakers as my goal is to dampen and remove all unwanted sources of sound (distortion) other than from the speaker drivers themselves.
Obviously speaker weight from heavy bracing and thick walls becomes impractical after a while - making the speakers so heavy that they are impossible to move...in practice this means all speakers have some unwanted cabinet coloration however slight that may be on the heaviest models. This is why folks like Pink Floyd work with speaker manufacturers to build their own super massively braced custom cabinets - construction overkill that would be impractical for most of us...
Speakers that are built like tanks (heavy damped walls and heavily braced) are less dependent on this aspect - blu tack seems to be the optimum stuff to avoid wobbles and deaden any induced vibration.
If you use a lightweight cabinet such as a Harbeth and many consumer designs then of course you do need to worry as the cabinet itself is an integral part of the sound - so any modifcation as to how it "breathes" or "waffles" will alter the sound...this is why stereophile measures cabint responses with an accelerometer to see what unwanted resonances the structure exhibits.
Personally, I use multiple layers of MDF and rubber pads below my speakers as my goal is to dampen and remove all unwanted sources of sound (distortion) other than from the speaker drivers themselves.
Obviously speaker weight from heavy bracing and thick walls becomes impractical after a while - making the speakers so heavy that they are impossible to move...in practice this means all speakers have some unwanted cabinet coloration however slight that may be on the heaviest models. This is why folks like Pink Floyd work with speaker manufacturers to build their own super massively braced custom cabinets - construction overkill that would be impractical for most of us...