Auralex Great GRAMMA V2 Isolation Platforms - 4 Pack(4) 1 3 4" x 19 x 30 Great GRAMMA v2 Isolation Platforms. Built on the success of the GRAMMA, the GreatGRAMMA v2 acoustic isolation platform is almost 30% bigger to float large speaker cabinets. Now 4x12s, 15" or 18" speaker cabinets will benefit from the awesome GreatGRAMMA. Only GreatGRAMMA v2 can handle the big rigs! Features: A tighter, more focused low end Hear the true sound of your amp, loudspeaker or subwoofer Instantly improve your sound on