The unignorable manifestation of this phenomena, using woods used as tuning devices, became highly apparent to me when I replaced my equipment rack. The very same rig, when placed on my new rack, sounds very different (and not in a good way) than my original rack sounded. I had to completely revise all of my platforms, footers, pods, cones, etc. in order to attain the sonic signature that I prefer. I still prefer the sound of my older rack but it was too small and way too overloaded for all my components.
Mike VansEvers offers an entire tuning kit, which is comprised of different woods fabricated into different shapes. The blocks are placed in various locations underneath components, &/or sometimes atop of or alongside of components (not so much for mass loading as) for resonance tuning.
Of course you may also place full size platforms made from different woods &/or other composite materials underneath of and atop of your componentry, which also accomplishes tuning adjustments. Anyone can easily discern the differences in sonic signature. Those who remain in denial may not have an adequate level of equipment or cabling quality, or perhaps listening skills may simply be deficient.