Comprised of three theatres totaling over 2,300 seats on the South Bank in London, the National Theatre presents an eclectic mix of new plays and classics, with seven or eight productions in repertory at any one time. The National has now upgraded its Sennheiser wireless microphone system and increased its facility to forty channels. Twenty-four channels of EM1046 receivers have been installed across the three theatres, while the remaining sixteen can be added wherever they are required.Mike Walker of Loh Humm Audio, who specified the system, in conjunction with the National Theatre sound department, comments, "As well as superb audio quality, we need systems that are physically robust and able to withstand the rigors of the 1,000 performances that the National presents each year. We auditioned other brands but never found anything to match the quality, durability and reliability of Sennheiser." The second set of outputs from each rack of EM1046 receivers is connected to an associated NetCira MS-8 rack-mount module that converts analogue audio to the Ethersound audio networking protocol. Using a modified NetCira ES6000 powered speaker as a headphone amplifier, the system provides remote audio monitoring stations around each theatre.