What do you put underneath floorstanding speakers?


I have B&W cdm7nt speakers on spikes and I was wondering if there was something to put underneath the speakers to improve the sound and also possilby reduce the sound in the apartment below.
ice2000

I'm using Mapleshades 2 inch thick plinths under my Totem Forest Signatures. 

I'm also using a 2 inch Butcher Block Acoustic plinth under my Teddy Pardo TeddyCap SE power supply and my Jay's Audio CDT2-MK3 Transport. 

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