RobinKidderminster said:
Whilst I order the concrete I can try wood but r the spks on spikes or rubber onto wood and spikes or rubber or flat on carpet for the wood? Lets call them bespoke wooden plynths with antiresonant acoustic treatment. And the electronics?
My first bit of advice was for your equipment rack.
For speakers, they need to be as steady as possible and level, completely isolated from the suspended floor and the right height.
If feeling adventurous, you could try a sandwich construction platform, made from 2 Granite Worktop Savers with a thin rubber or sorbothane layer in between. If it wobbles on the carpet, you can (if possible) rest the Granite on 4 little screws that have been screwed into the floor and adjusted to leave the Granite level.
If not feeling adventurous, just use one slab....get these from somewhere that they can be returned to, if not effective.
I would use the spikes into spike shoes.....which can, is necessary, be made by punching a dent into 1Ps, and sticking laminate floor savers on the other side.
Any stands should be filled with rice/sand, and Blu-tak used under the speaker.....this again acts as isolation. Remember that metal spikes couple a speaker to what it's sitting on, which is why spiking speakers into a suspended wooden floor isn't always ideal.