I am afraid that the only place where this can be put to test would be in an extremely quiet studio or better of - in an anechoic chamber. This way self resonance can be explored although in the case of a piano specific strings should be addressed because some of them might have sympathetic resonance to such floating board. Most pianos are too heavy on the lower mids (muddy sounding). With baby grands that might not be the case though. A big brand built special facilities for such research.
I am afraid that the only place where this can be put to test would be in an extremely quiet studio or better of - in an anechoic chamber. This way self resonance can be explored although in the case of a piano specific strings should be addressed because some of them might have sympathetic resonance to such floating board. Most pianos are too heavy on the lower mids (muddy sounding). With baby grands that might not be the case though. A big brand built special facilities for such research.