Powerful – the voice of the ocean silences the wind.

The giant “Vox Maris” organ at the Sky Tower in Yeosu, Korea was completed and erected in time for the Expo 2012. Now, the “voice of the ocean” will roll across the entire Expo site and the bay of Yeosu.

Vox Maris was Orgelbau Hey’s largest ever project to date. Designed and built for Expo 2012 in Korea, the innovative, six and a half octave aerophone is expected to form an acoustic symbol and one of the major attractions of the World Fair. The gigantic open-air organ is equipped with 80 wind and weather-proof copper pipes towering up to 10 metres high. The giant instrument is integrated into an ornamental structure on the outer tower that resembles a harp and is shaped like an ocean wave. And of course the pipes need to be supplied with compressed air.

The stated aim of the project creators was to make the organ as loud as possible – while also delivering a balanced, acoustic experience. This was no easy task – especially on the coast with unpredictable wind. Another requirement was that the organ should be able to be played with lower pressure, similar to being in a concert with other instruments.

The solution was clear – a Kaeser compressor. A Kaeser SM 6 has already successfully been in use at Hey organ builders for many years. A Kaeser specialist knew what to do: the DSD 202 T, a rotary screw compressor that delivers 20,000 litres of air a minute, should do the trick. At 8 bar, the pressure applied to the "Vox Maris" pipes is a thousand-fold that of a church organ. At the same time, the DSD 202 T is flexible enough for quieter sounds.

On the day of the Expo opening, the "Vox Maris" pipes reached their crescendo, which spread out powerfully in all directions, and could be heard as far as six kilometres away. According to the Guinness book of records, at 138.4 (db)A, the sound sculpture is currently the world's loudest organ.