“Organisations like the Association of Radio Industries and Businesses are discussing standards for next-generation broadcasting, and three-dimensional audio is under consideration,” says Sadanari Iwahashi of ABC’s production engineering department. “When we thought about a broadcasting van which could be used 15 years in the future, we concluded that it’s necessary to support immersive sound.”

The move is a coordinated initiative across the ABC group. In addition to the remote truck, its MA (Multi Audio) room has also been upgraded to a 5.1.4 immersive format. “When broadcasting starts to support immersive, we’ll be able to monitor the sound live from the site, and recordings can be brought into the immersive MA room for further processing,” says Iwahashi. “It makes sense to have an OB unit ready to record immersive sound for many reasons. For example, when we record a concert, we can approve the use of the sound in other events and programmes as well. It’s also important that we have four monitors installed in the ceiling from the start, so we can just begin immersive monitoring without the hassle of setting up.”

The L-C-R (left - center - right) channels are handled by three 8341 coaxial studio monitors, and thanks to a custom-designed 2.2 m high production room, ABC was able to mount four 8331 height monitors in recesses in the ceiling. As the smallest model in The Ones series, the 8331 is perfect for small rooms where space is limited, and this unusually high ceiling meant that they could be placed at the same distance from the listening position as the L-C-R monitors in the front. Low frequency duties are handled by a 7360 subwoofer.

“The goal was to ensure as much distance between the monitors as possible,” says Iwahashi. One particular challenge was the position of the left and right rear 8331 monitors, which due to the structure, would be closer than the L, C and R monitors. The ideal angle for rear channel monitors is 110 degrees +/- 10 degrees, but if we positioned these and the L-C-R channels equidistant to the listener using that angle, they would exceed the width of the van! So we compared the sound prioritising the angle and then the distance many times, and in the end we decided to prioritise the angle. In order to maximise the distance, the rear monitors were also installed slightly above the horizontal position, at an elevated angle.”

As Smart Active Monitors like The Ones integrate closely with GLM software, ABC was able to compensate each monitor for frequency response, playback level and distance delay. In fact, according to Iwahashi, GLM created the perfect environment for accurate immersive monitoring – despite the acoustic demands of the space. “We adjusted the angle of each monitor, fixed the reflections with sound absorption, calibrated them and then repeated the listening and fine-tuning process,” he explains. “GLM software was a great help in building an ideal monitoring environment. The visualisations of frequency dip points were easy to understand too.