The minute you start playing the whole speaker/floor/room system starts vibrating. If you somehow magically decouple or float the speakers in mid air this will stop the vibrations getting into the floor mechanically, but not acoustically. Also the more the speakers are decoupled like this the more it is the speaker mass alone holding them still. Since we do not want the speakers to move at all this is a very bad situation that can only rob the music of its life, vitality and dynamism.
What we want is something under the speakers that is rock solid, and preferably massive so it will help to hold the speakers still and not move- also because the more it moves the more it transmits energy into the floor.
Normally this is a tough one and I recommend BDR Cones as the most cost-effective solution. In your case however since you actually want to raise the speakers 4-8 inches higher we can do better.
The relatively cheap way is a slab of granite. Sold as machinist plate they are probably around $150 or less each for the size that you need. Each one will be around 100lbs and they are around 4" thick. With BDR Cones under the speakers you would then experiment and tune with something like sorbothane or other damping material between the granite and the floor. This mass will bring real improvement in dynamics, bass slam and impact. The Cones will massively improve inner resolution and detail. And the mass and damping material underneath will greatly reduce floor vibrations.
A really cheap solution is the same thing except with a sand bed instead of granite. With this one you still use BDR Cones but use MDF on top of the sand, and fine tune with different thicknesses of MDF. Mix a little mineral oil in with the sand, just enough to eliminate dust and scatter.
You can see both techniques in use in my system here https://systems.audiogon.com/systems/8367
The turntable combines all these techniques with a granite machinists plate sitting on a sand bed, which is made from cast concrete. The phono stage is sitting on MDF on top of a sand bed. The Melody amp is on granite. All of these are fine tuned with dampening here and there. The speakers use BDR Cones with BDR Round Things under the Cones.
What we want is something under the speakers that is rock solid, and preferably massive so it will help to hold the speakers still and not move- also because the more it moves the more it transmits energy into the floor.
Normally this is a tough one and I recommend BDR Cones as the most cost-effective solution. In your case however since you actually want to raise the speakers 4-8 inches higher we can do better.
The relatively cheap way is a slab of granite. Sold as machinist plate they are probably around $150 or less each for the size that you need. Each one will be around 100lbs and they are around 4" thick. With BDR Cones under the speakers you would then experiment and tune with something like sorbothane or other damping material between the granite and the floor. This mass will bring real improvement in dynamics, bass slam and impact. The Cones will massively improve inner resolution and detail. And the mass and damping material underneath will greatly reduce floor vibrations.
A really cheap solution is the same thing except with a sand bed instead of granite. With this one you still use BDR Cones but use MDF on top of the sand, and fine tune with different thicknesses of MDF. Mix a little mineral oil in with the sand, just enough to eliminate dust and scatter.
You can see both techniques in use in my system here https://systems.audiogon.com/systems/8367
The turntable combines all these techniques with a granite machinists plate sitting on a sand bed, which is made from cast concrete. The phono stage is sitting on MDF on top of a sand bed. The Melody amp is on granite. All of these are fine tuned with dampening here and there. The speakers use BDR Cones with BDR Round Things under the Cones.