I have done a lot of investigations into using structures under audio devices that have a design intent to isolate the device from transferral of ambient energies within the listening area.
CDP's CDT's and DAC's have all benefitted from this type of Support Structure when used in my own home and on devices in systems in other homes.
To date I have found the best end sound had been through using 2 x Tiers of Panzerholz as Sub Plinths. The P'holz is separated by AT 616 Footers, the method has superseded other methods and proved to be very valuable at creating the Support Structure that really tidies up the end sound.
More will be achieved, better/worse, when trying out additional footers types between the Top Tier and the Audio Device, bypassing the devices supplied footer.
I have learnt there is not a ubiquitous method that works for all listening environments, playing with configurations of materials is required.