Because of the levels of noise produced by musical instruments within a small space, the only way to keep the noise contained is to construct a room within the garage or shed. This involves constructing stud work away from existing garage/shed wall (gap 5-10mm) The soundproofing products required in the Walls and ceiling for this task are:  Acoustic Wool,  Resislient bars, Acoustic plasterboard, Soundmat or membrane and sealant