With its origin dating back 2,000 years, Ryōgoku Kokugikan (Ryōgoku Sumo Hall or Kokugikan Arena) is the only building dedicated to Japan’s national sport, Sumo wrestling – such is its status, there is no-one in Japan who has not heard of the Tokyo venue. Sumo wrestlers practice here daily, dreaming of winning the Gift Cup. His Majesty The Emperor sometimes comes to watch, and has seats permanently reserved for him.
But Ryōgoku Kokugikan also hosts various other events during periods when sumo is not being held, including wrestling, concerts and corporate events. The arena therefore required a PA that could reproduce, intelligibly, everything from quiet to loud sound reproduction for wrestling in the ring. It also needed to be heard right up to the last row of seats on the second level balcony.
‘In such a way we can create a realistic atmosphere and overcome all the challenges,’ says Sumio Akashio, sound engineer at the Ryōgoku Kokugikan.
In planning the system upgrade Takahisa Ota from Audiobrains conducted a simulation, using Martin Audio’s Display 3 modelling software, and found that the manufacturer’s WPS line array, in the correct configuration, would be best suited to accommodate the various events hosted in Kokugikan – in terms of size, weight, clarity, and SPL. In addition to WPS an SXCF118 cardioid subwoofer provides the deep bass requested. Some 80 WPS cabinets and eight SXCF118 subs were deployed in total.
Martin Audio’s Torus also features in the shape of eight T1215 (four pairs per side) for near fill. By being directed downwards these are able to deliver sound without reflections to the VIP areas, where it had previously been difficult to achieve clarity due to the influence of the roof, suspended above the ring. No other satellite speakers are now required, and each pair can be used to control the SPL within its specific area as required.
Takahisa Ota, who carried out the installation, made the necessary system adjustments to ensure coverage, consistency and control throughout the stadium. ‘In the vertical pattern I managed to maintain clarity at the rear while at the same time suppressing any reflections,’ he says.
