Need help modifying existing practice room

[ckf]

I built a 4x8 room to practice my guitar in in the corner of a basment.  Two walls are exterior cinderblock.  The other two are 2x4 studs with 3/4 fire rock on each side with R-13 insulation in the middle.   I added two layers of the 3/4 rock and a 2" layer to pink foam insulation between them.  On top of that I've added a bunch of moving blankets attached to the walls inside.  One wall is a 4x8 swinging door that has an interior and exterior layer of 2inch pink foam insulation.   

It's pretty quiet but I'm wanting more.   Should I coat teh interior walls and ceiling with MLV and then rehang the moving blankets?   I can't pull the drywall and wish I would have put it in then.  Any other ideas for further db reductions.  I have a large tube amp and want to crank it.  I can now turn it up but want it louder.

[Randy S]

Use our SSP foam mat in 1" thickness, cover the entire room. This will give you the extra boost your looking for.
http://shop3.mailordercentral.com/supersoundproofing/prodinfo.asp?number=09%2D42730%2DPSA