Up to 32 additional rooms can be supplied with music in perfect sound quality via the Revox M51 central unit. The system offers access to a CD/DVD player and up to 4 FM tuner units, enabling various stations to be heard around the house. Four different listening zones of up to eight rooms each can be defined in up to 32 rooms. The Gira operating units for controlling the system are available in each room For the secondary rooms, Revox M219 room amplifiers are required, which supply the local loudspeakers. The optional integration of a Revox M37 audio server enables the management of an extensive music collection of up to 400 hrs. in length.