Recording studios are usually divided into three areas: a "live area" (with natural ) for recording groups, a "dead area" (with to prevent reverb and echoes) for vocals and soloists, and a control booth, to house the recording equipment. Studios are usually soundproofed, to keep outside noises from getting into recordings. and other objects are used inside studios, to isolate sound sources. room shapes are also used, to prevent "standing waves" and sound interference.