The basic design of radio studios has changed little over the last 90 years. But operational considerations, new acoustic techniques, evolving technologies and financial considerations have made engineers and designers take a different approach to a long-established format.
Last year's 90th anniversary of BBC Radio was a timely reminder of how the venerable medium has developed over the years. But a constant has been the radio studio, which has invariably been a voice booth for the presenter and guests, with a control housing the technical equipment, engineer and production team.
This model has been used by broadcasters - both public and commercial - of all nationalities since the 1920s. Because it works and served well for so long people have not considered changing the template much but in the 21st century a variety of factors is making engineers, designers and architects reassess how a radio studio works and what it should look like.
A major shift in attitudes is that studios today do not have to be at a distance from the production offices or newsroom - often on another floor of the building - or to the highest acoustic specifications. This has been seen particularly at smaller stations but among the most striking examples is the BBC World Service glass studios, which it first began to use over ten years ago and now has installed into its new home at Broadcasting House in London (pictured).
The concept was formulated by Nick Sheridan, head of technology for BBC Global News, who outlined the project during a presentation at last year's Radio Academy TechCon. "Radio is changing and that is especially true for the World Service, despite its traditional image," he said. "When we were still at Bush House we started to look at production facilities for the future, with studios not just on the same floor as the offices but right next to them."
Sheridan and his colleagues came up with the idea of a glass box near the producers' desks that could be used whenever something needed to be recorded. "We wanted to have everything within the box, with no apps room," Sheridan explained. He added that although the studios were small enough to fit in the office space, the glass would make them feel big to the person inside.
The choice of material caused many acousticians to balk at the idea, despite Sheridan's assertion that it would be appropriate for speech radio, which does not need top specifications. Acoustic consultant Andy Munro was among the few not to dismiss the idea. "He didn't think we were mad," said Sheridan.
A prototype was built at Bush House, featuring three glass panels and a back wall containing absorbent material. Even with only a single door, Sheridan said this produced an isolation of 40dB and a reverberation time of 0.15 seconds. "We were aiming for a NR [Noise Rating] of 30 but achieved 25," he added.
Six glass studios were built at Bush House for the South Asian Service and when the time came to move the entire World Service operation to the "New" Broadcasting House, the same approach was taken. 28 boxes, arranged in clusters of two or three, have been built; the big change is that they are glass on all four walls, with isolation built into the ceilings. Removable blinds can also be used on the rear wall for additional absorption.
Sheridan acknowledged that getting the construction right, with the glass sides making secure joins, was not easy but it was achieved. Each box is self-contained, with its own Studer OnAir 3000 mixing desk and ancillary equipment. Although some presenters are using headset microphones, Sheridan commented that AKG 414s, which have been among the standard BBC voice mics for many years, are also being used.
An isolation value of 44dB and a NR of 20 have been reached with the new studios. Sheridan explained that staff working near the boxes know recordings are being made and so keep any noise to a minimum. There is, however, still doubt about how good these structures are. British satirical and investigative reporting magazine Private Eye last year carried a story quoting anonymous members of World Service staff complaining about the sound quality.
Sheridan responded that "there will always be rumblings", referring to rumours of discontent, but said people he had spoken to were happy with the glass boxes. "For speech radio they are more than good enough," he said.
A major driver behind the innovative design was to save money on conventional build studios. Sheridan gave the cost for each box as £600,000, which he said was higher than at Bush House because of the four wall construction. There are also ten traditional two box studios, which cost £5.5 million, compared to £4.5 million for the rest of the World Service facilities.
Despite the glass design and self-contained nature of the boxes, they still have an operations area outside for the studio manager, something that adheres to traditional layouts. So until noise cancelling technology is good enough to do without some kind of enclosed space, the basic blueprint of radio studios is still not changing that much, even if they are made of fused sand, soda and lime.