Speakers on a suspended wooden floor

I have Cyrus CLS70 speakers with the dedicated Cyrus Tripod stands, currently sat on spikes and spike shoes, resting on a suspended wooden floor.

What is the best way to maximise the audio quality? I feel that the sound may not be optimum at the moment, as previous experience of suspended floors has revealed that all the life is taken out of the music. So, I am open to suggestions of what to do to get the most out of my speakers.

I second Ian's suggestion.

Granite or slate out of preference?

Local DIY store has grey granite or slate slabs.
Granite is 50cm x 50cm x 2cm, weighs in at 13.5 kg per slab. 4 slabs would cost me €40.
Slate is 40cm x 40cm x 1cm, weighs in at 3.2kg per slab. 6 slabs for €35.

Obviously I would stack them up (and probably glue them together), but which will be better?

Tempted by the Granite as it's heavier.

Stone/concrete plinths work on bare wooden floors, less well on carpeted floorboards in my experience. I add mass to the stands, usually weights on top of the bass of the stands. And make sure the spikes are nailed (!) into the floorboards.

My test is do the speakers wobble if you push either side or the front/back? The floorboards are a resonant panel and you can't stop all resonance, merely dampen it.

Paving slabs work as a plinth, bringing different floorboards together and they are cheap. Paint or wrapping them in fabric may help with the aesthetics. I have tried bolting slabs to the speaker stand using the threaded holes for the spikes, feels more rigid but the floor still moves. Not sure I could hear a benefit.