Box in a Box is the right combination of the floating floor, acoustic walls and the acoustic ceiling. The main purpose to apply a box in a box system is to reduce the flanking noise between edges. This system can perform a noise insulation up to 70 dB (A). The installation of this system start by the floating floor where the original slab should be well levelled and smooth, to distribute the elastomeric pads, wall decoupling materials, laying the cement boards to construct the concrete floating slab. After concrete pouring to install the concrete or dry walls laid on the floating floor and shifted from the existing walls a certain distance based on required performance and original constructed envelop. The connection of the floating walls will be by acoustic isolation hangers. Finally the acoustic ceiling will be constructed and attached by the existing celling thru acoustic elastic hangers or steel springs according to the required performance.