Recording studio floor

[spaceroad]

Hi guys.
I have a 20 x 15 foot building at the end of my garden, that was originally built as a rehearsal studio. It's about to go under reconstruction, including the ripping up of the floor and joists right down to the concrete pad that it all rests on.
The floor and joists are raised too high off the concrete pad, creating a huge sub bass trap which is not helping with the neighbors. I need to eliminate this as best as possible.
The plan is to lower the floor and joists to sit very close to the concrete pad.
I'm looking for advice on what is best to do and which products?
I've read about creating a floating floor which makes sense to me and possibly resting the floor joists on rubber pads, sitting on the concrete base. I've also been told that a layer of sand would also be sound a good sound absorber, however I'm not sure about moisture issues.
There is also the issue of what to put in the cavity in between the floor joists? At the moment I have just the standard pink insulation. Can I re-use this?
My plan is to re-use the 8x4 sheets of ply wood which make up the current floor. However, I'm going to cover this is a new hard wood flooring. If this is recommended?
Any advice would be well appreciated.
Thanks,
Nick.

 

[BassBallz]

Sometimes sand can be used to absorb the sub low frequencies coming off a stage. There are actually some clubs that put sand under the stage to tighten up the sound throughout the room.

In your specific situation i'd suggest isolating the gap area to keep moisture out, add some sand after you've established the new floor over rubber supports. Basically use all of your ideas. The rubber pads will keep some of the low end from being sent out too far (neighbor's house). The sand will also help absorb those sub-lows which reach peak resonance many dozen feet away. It will also tighten up the kick drum and bass guitar. You might also want to invest in some isolation foam pads to put on the walls, those will also absorb more sound, deadening the room, lessening guitar feedback and your neighbors will thank you.