Situated in the western Hungarian city of Győr, the new state-of-the-art Aqua Sport Center is based around a full 50x25-metre Olympic sized swimming pool.
Built on an 10,000 sq. meter site, much of it in metal and glass, the viewing area comprises 800 fixed seats and 400 optional chairs, while ancillary features include a 16x10 meter educational pool, two saunas and plunge pool, jacuzzi, relax room, fitness rooms and changing rooms.
At the planning stage last September the need for a good sound system to function intelligibly in this reverberant space was recognized and according to Imre Makkay from Chromasound Kft, RCF’s long-term Hungarian distributors, one of their local system integrators, G-Sound had the opportunity to fulfil the specification with an RCF solution, having already successfully outfitted the Audi Arena Győr with the brand.
The owner of the company, József Gricz wrote the specifications — which were readily accepted by the pool management — and conducted an electro-acoustical simulation.
From RCF’s large product portfolio he based his system design around ten P4228 indoor/outdoor, weatherproof (IP55-rated) wide-dispersion, two way loudspeakers, designed to offer substantial power and efficiency. The HF section is a constant directivity CMD horn loaded with a 1.4” RCF precision compression driver with a 2.5” diaphragm assembly for wide dispersion while the LF transducer is a double 8” woofer with a 2.5” voice coil.
There are three main grandstands surrounding the pool and down both long sides they have installed four speakers, and a pair on each end that includes standing and seated VIP areas in one of the corners, with a gallery.
The speakers are hung directly above the water and installed horizontally under the electrical cable trays on uniquely designed, certified, stainless steel consoles. “We were lucky because the electrical cable tray consoles were sufficiently strong to support the lightweight speakers,” said Gricz. “We’ve defined distances from the seats to the speakers, mindful of the horn’s 110° x 60° dispersion angles.”
The speakers are divided into five zones, and with a dedicated DX4008 4-in/8-out digital system controller installed in the technical room, there are free I/O’s for future needs.
Each half of the pool area is served by its own amplification rack positioned close to the speakers in order to shorten the low impedance cable runs. The system is driven by a total of five RCF IPS 3700 stereo amps, delivering up to 2 x 1500W RMS@4Ω.
The challenges faced by G-Sound and Chromasound were all the result of the many flat surfaces (glass, water, and walking areas), and with minimal acoustic treatment, the average time decay was 4.5 sec. “Our main goal was to reproduce sound accurately an intelligibly to populated areas — not only the spectators in the stands but coaches pool-side and competitors on the starting blocks.
“The budget was limited, and we needed to produce high SPL and even tonality not only for spoken word but also jingles and background music.” Since the water recirculation and air handling unit operates at a level of 66 dB LAeq the system needed to deliver a minimum 20 dB higher SPL to every seat.
However, the RCF system has fulfilled all expectations. After fine tuning, the Speech Transmission Index’s average was measured as STIPA 0.48 in normal conditions (all zones operating to empty grandstands), and STIPA 0.41 at worst conditions (all zones operating alongside normal building automation). The maximal sound pressure level was 104.2 ± 1.1 dB LAeq and 119 dB ± 1.5 dB LCpeak. “The frequency response was quite good … within ± 1,5 dB in the 80 Hz-10 kHz province — despite the high humidity inside the building,” records Imre Makkay. Because of the symmetrical structure of the pool, they could use virtually the same processing in all zones.
Summing up, he says, “Those tiny but extremely loud speakers with carefully chosen colour are lost in that huge space, with everybody wondering where the sound is coming from.”
Chromasound offered full project support throughout in the form of Balint Redei and Balazs Toth who worked alongside Andor Furjes (aQrate Ltd.), who assisted with control measurements.
Finally, as construction of the swimming pool only amounted to part of the HUF 9.6 billion (€31 million) in development funds allocated, building works are to be continued next year with an open-air pool and areas for athletics contests, tennis matches and a football pitch.