The sound insulation is the set of processes implemented for getting a determined noise reduction, i.e. limiting the transmission of sound from one space where noise is generated toward another that one wishes to protect. The reverberation control consists in the implemention of absorbing materials in a premise in order to limit its reverberation time (the persistance of sound after a noise source has been shut off), and/or to increase its spatial sound decay, i.e. to improve the inner acoustics inside a premise by limiting the amplification of sound levels due to the phenomenon of reverberation