GTX 7C Brings Precise Directivity Control to BBC Proms at the Glasshouse International Centre for Music

The BBC Proms, organized by the British Broadcasting Corporation (BBC)—the United Kingdom’s public service broadcaster—are the world’s largest annual classical music festival. Established in 1895 and presented by the BBC since 1927, the festival features leading orchestras, conductors, and soloists, with performances broadcast nationally and internationally across television, radio, and digital platforms.

Given the architectural and acoustic constraints of the temporary venue, selecting the appropriate sound reinforcement system was critical. With orchestral musicians and sensitive broadcast microphones positioned in close proximity to the loudspeaker system, TT+ Audio’s GTX 7C active cardioid line array was chosen for its variable cardioid pattern control, enabling precise directivity control while adapting to multiple stage configurations throughout the concert series.

The GTX 7C provided the main reinforcement, supported by GTS 16C cardioid subwoofers. For contemporary performances requiring greater low-frequency output, GTS 29 dual 19-inch subwoofers were deployed to add energy in the first octave (infra-bass), while GT 8 point source loudspeakers served as front fills and out fills.

The system’s variable cardioid technology provided the flexibility to accommodate multiple stage configurations throughout the concert series.

“The performance area is a large atrium rather than an acoustically neutral concert hall, so selecting the right sound system was extremely important,” says Andy Magee, System Designer at TT+ Audio. “With multiple stage layouts and the orchestra positioned close to the PA, the GTX 7C’s variable cardioid pattern control allowed us to optimize coverage while reducing acoustic energy reaching sensitive microphones.”

This project was among the first major UK deployments of the complete GTX 7C system. Despite the temporary ground-support structure, installation was efficient, and ground-stacked delay arrays ensured consistent coverage throughout the venue. The modular system also supported various stage layouts during the performances.

The concourse, measuring approximately 80 m long and 30 m high with extensive marble and plaster surfaces, presented acoustic challenges. The system’s directivity control minimized unwanted reflections and maintained clarity for both the live audience and the BBC broadcast mix.

Production staff and broadcast engineers all reported positive feedback on the system’s performance throughout the event.

“The challenge wasn’t achieving level; it was achieving control,” said Graham Orchard, Technical Manager at The Glasshouse. “In a space like the concourse, keeping acoustic energy off reflective surfaces and away from the stage, particularly with acoustic instruments, is just as important as covering the audience. The GTX 7C gave us the control we needed, and together with a well-planned system design and an experienced engineering team, it allowed us to achieve a result that simply wouldn’t have been possible in this space otherwise.”

“We delivered around 95 dB SPL at front of house while significantly reducing PA spill into microphones that were only about 4 m from the loudspeakers,” Magee adds. “Considering the acoustics of the space, achieving that result with almost no system equalization was particularly satisfying.”

The project demonstrated that the variable cardioid technology of the GTX 7C and GTS 16C delivers precise directivity control in acoustically challenging environments, meeting the demanding technical requirements of large-scale live and broadcast productions such as the BBC Proms.