Once again in testament to the burgeoning popularity of the Christian faith in South Korea, Seoul has recently been centre stage in the dedication of another 'super' church. Travelling throughout Seoul in an evening it is very hard to ignore the neon crosses that punctuate the night sky, however the latest House of Worship to welcome believers within Seoul is of a truly grand scale.

Since its inception in March 1986, Yonsei Central Baptist Church has seen an astonishing growth. Initially based in a small 198m² basement, Yonsei Central Baptist Church now boasts two houses of worship located in Seoul and a training centre in the nearby city of Suwon. In addition to this there is also an active overseas presence with over 80 preachers operating in countries such as China, Kazakhstan, Nepal and Senegal. The rapid growth of the church and the resulting requirement for larger facilities culminated in the purchase of land at the base of Yonsei's Prayer Mountain, located in the south west Gung-Dong, Guro-Gu, district of Seoul. This land was designated to provide not only a church, but also training facilities and amenities for the local community. The Yonsei Central Baptist Church may not have the largest membership of the many churches throughout South Korea; however the new construction is by far the largest in size. The entire site occupies a total area of 43,000 m² while the main construction itself occupies 44,700m² of floor space. The church building comprises over 244 rooms with the main Jerusalem sanctuary seating over 10,000 worshipers and an additional youth room (the Andiok room) seating a further 3,000. The building spans six floors with underground parking accommodating over 700 vehicles.

Construction of the church commenced with a ground-breaking ceremony in July 2003 and after 21 months of construction the church held its inaugural service on the 5th May, 2005. The entire acoustic design and installation of all audio and visual related infrastructure was managed by Seoul based Dreamsound, working in close collaboration with Motive Co. Ltd, the interior design consultants.

Constructed with a single balcony, the over 10,000-seat Jerusalem sanctuary occupies three floors of the building and excluding its impressive size, one noticeable feature is the absence of any visible obstructions (such as supporting pillars) anywhere within the room, allowing everyone a perfectly un-obscured view of those conducting the service. Meanwhile, in order to give an impression of the size of this room, the stage area for the Choir/Orchestra alone totals 991m².

With a building of this size much care was taken in the selection and implementation of the audio equipment and infrastructure. The selection of the audio equipment was led by Pastor Yoon himself, with the help of his technical team comprising of Kim Hong Tae - Chief Engineer and Director for video, sound, lighting and recording; Lee Hwan Cheol - Senior Sound Engineer and responsible for both indoor and outdoor worship productions; and Park Byung Jun - Junior Sound Engineer with responsibilities as the audio/video recording engineer in addition to the management of the networked audio infrastructure.

Within the overall construction a total of 12 representative rooms required fully featured and high quality audio systems to be implemented. These are the main Jerusalem sanctuary, the Andiok youth room, six Theme and four Prayer rooms. Selection of the correct speaker system for these rooms was of paramount importance to the Pastor as he knew very well the performance criteria he was looking for, as Mr. Park explains, "In general within a House of Worship the most important factor for any amplified source is intelligibility. It was vital for Pastor Yoon's voice to be projected in a clear and intelligible way. However, it is also common in South Korea for religious services to contain a mix of solo voice, orchestral/choral performances and indeed very dynamic rock performances. The dynamic range of our services is really quite astounding. This meant that we needed to have a speaker system that had the capability and capacity to operate effectively over this very wide dynamic range. In fact, when we have Christian rock bands playing it is quite normal for us to measure readings of between 110dB and 130dB SPL."

In order to evaluate which speaker system was best suited to the task it was decided to audition products from all the major international speaker manufacturers, outdoors and back to back. The same audio material (recorded onto compact disk) would be played through each system with the disk containing a recording of Pastor Yoon's voice, in addition to orchestral recordings and various heavy rock tracks. This process took place back in February 2004 and according to Mr. Park, "Pastor Yoon knew what kind of response was required and the need for a speaker system to ably perform under such an extreme dynamic range, whilst being 'pure' and uncoloured with his voice. The one system that was unanimously chosen at the conclusion of the auditions was the L-Acoustics V-DOSC. We all felt that this speaker system provided us with a very clear and intelligible result for the Pastor's voice, which was very important, while it performed equally as well with the heaviest material we could test it with. The auditions were very intense."

With L-Acoustics chosen as the principle speaker system for the entire project, Dreamsound and Mr. Park looked towards the implementation of the audio system and infrastructure.

Taking into consideration the sheer number, and size of rooms within the building it was decided that an investigation into the benefits of analogue and digital audio transmission systems be conducted. For analogue, the major concern was distribution and control of the audio throughout the complex, in addition to the signal losses, reduced bandwidth and induced interferences that can occur when distributing analogue audio over extremely long cable lengths. A digital distribution system suited the application far more with the ability to control all stages of the audio infrastructure including level, routing, and speaker management all within one box. Therefore in terms of functionality and flexibility the digital networked audio solution proved to be the best solution. Looking at the technology available a decision was finally taken to implement the new BSS London blu-80 signal processors, all fitted with the Peak Audio CM1 CobraNet module. Each blu-80 allows a maximum of four input or output cards to be installed depending on application and all units within the system were linked via CobraNet (using traditional CAT5 cabling and industry available network hubs) with system configuration managed via the BSS software design package London Architect. In addition to providing audio networking and control functionality the blu-80 devices were also able to serve as the speaker management systems to the various L-Acoustics speakers installed throughout the church complex. Yonsei church is in fact the first fixed installation in South Korea to utilise the BSS London.

Because of the need to operate within the digital domain, it was a pre-requisite of Pastor Yoon that all of the audio consoles employed within the church be digital. Three consoles were required and the console finally chosen was the new Trion from Nashville based manufacturer Harrison. Two of the Trion consoles were installed in the Jerusalem and Andiok rooms, while the third serves as a dedicated post-production console. The church is fitted with two state-of-the-art video control rooms (designed with assistance from the South Korean broadcast company MBC) enabling the church to produce its own programming material. The main console DSP engines are all installed within the central machine room (adjacent to the post-production studio) with audio interconnects between the remote ADC and DAC I/O units being either optical or 75 Ohm coaxial depending on the length of cable run required. With the Harrison accepting coaxial MADI streams multiple RME ADI-648 devices are utilised to convert the MADI stream from Coaxial to Optical or vis versa. A single Cadac 16 channel M16 remote microphone amplifier is also installed within the main Jerusalem sanctuary for use with principle vocals and connects directly to the Harrison via MADI. In addition to providing FOH facilities, the Jerusalem and Andiok installed Trion consoles also provide monitor mixes to the stages via stage-side remote controllers.

In total there are over two hundred L-Acoustics speakers installed within the church. The main Jerusalem sanctuary is installed with two V-DOSC line arrays located either side of the main stage in a left - right configuration. Each line array consists of four SB218 subwoofers, followed by seven V-DOSC cabinets and finally three dV-DOSC enclosures providing down fill. Front fill is achieved via eight MTD-108a passive two way speakers, cleverly concealed within the steps leading up to the front stage area, while side fill is provided in the form of two pairs of ARCS mounted either side of the stage area. The balcony delays also follow the left - right arrangement and each consist of an array of eight dV-DOSC, while under balcony delay is provided in the form of four separate arrays to provide an even coverage over the wide seating area, each consisting of four dV-DOSC. For stage monitors, twelve of L-Acoustics' two way passive MTD-112b wedge cabinets are available, in addition to six of L-Acoustics' new K-louver modular directivity technology KUDO cabinets, for use as Pastor Yoon's solo monitors.

Unlike the Jerusalem sanctuary which is primarily used for worship, the role of the Andiok room is somewhat varied. In addition to providing a space for worship, the Andiok youth room is also utilised as an entertainment venue for concerts and performances/recitals, while it even serves as a movie theatre with full surround sound. As the room is approximately one third of the size of the main sanctuary the more compact dV-DOSC line array was chosen as the main L-R speaker system. Each array is configured with two dV-SUB subwoofers mounted above six dV-DOSC. The dV-SUB is a vented triple 15" high level compact subwoofer, designed to be compatible with the dV-DOSC active two-way speaker unit. A further two SB218 dual 18" subwoofers are flush mounted within the walls on either side of the stage area to provide extended bass response down to 25Hz. In contrast to the Jerusalem sanctuary, six ARCS are flown directly above the stage along a horizontal axis to provide a centre cluster. According to the design team, ARCS were chosen for the centre cluster because of its predicable and precise coverage pattern, in addition to offering the same Wavefront Sculpture Technology (WST) as found on room's dV-DOSC line arrays. Side fill is achieved through the use of a pair of ARCS mounted either side of the stage, with eight MTD-112b wedges being made available for monitoring and four KUDO cabinets for Pastor Yoon's voice monitors. Four MTD-108a speakers are provided for delays while a further sixteen MTD-108a cabinets are utilised for surround (split into two groups of eight to provide surround left and surround right).

For the six 200-seat Theme and four Prayer rooms, a system of mobile racks have been employed providing microphone amplifiers, mixer, speaker management systems and power amps. These racks can also hook directly into the main audio network allowing any service within the main sanctuary to be relayed within these rooms. Each room has the capacity to seat approximately 200 worshipers. Each of the six Theme rooms are fitted with a pair of BagEnd TA6000-I two way passive enclosures specifically developed for speech reinforcement, while the four Prayer rooms are all provided with two L-Acoustics MTD-115b switchable active/passive two way enclosures. Three of the Prayer rooms also include the TA6000-I enclosures for delay.

Power amplification for the entire complex is provided by a mix of over ninety Lab-Gruppen amplifiers including the two channel Fp6400 (2 x 2300W into 4 Ohms), Fp2600 (2 x 840W into 4 Ohms) and the four channel Fp2400q (4 x 380W into 4 Ohms.)

The audio and video installation was a major undertaking on the part of Dreamsound due to the shear size of the project. Dreamsound's on-site involvement in the project spanned ten months with the project team comprising of, on average, ten engineers working with the assistance of the 3,000 strong on-site workforce. The project team was headed up by Mr. Seo Sang Woon, Technical Director of Dreamsound. Mr. Seo was instrumental in the overall implementation of the system design in addition to developing a number of custom solutions for the project including all tie-line and breakout panels, and distribution systems. With the high number of rooms within the church, and low number of staff available to manage the facilities, Mr. Seo needed to design a system that enabled the staff to remotely control all key functions of the audio system including power, audio routing and levels etc., in addition to the ability to remotely control all key video facilities within the complex. Such a system has now been implemented and taken one step further, whereby all audio systems within both the main church complex and the adjoining training centre (a total of 23 rooms) can now be fully remote controlled.

The three months prior to opening were the most intensive for Mr.Seo and his team, however everything came together on time. To the delight of Mr. Park and the other members of the Church audio team, all speaker systems were tuned, with the assistance of L-Acoustics' Paul Bauman, in just three days. Mr. Park enthused, "There were no problems at all when the speaker systems were installed. Everything went according to plan which is a great credit to Dreamsound for their acoustic and systems design."

The Main opening ceremony was held on the 5th May and according to Mr. Park, "the reaction from our congregation was one of awe and great emotion at seeing the size and construction of the church and sanctuary. The entire audio system performed flawlessly and gave us the exact results we were looking for." For the engineers at Yonsei Central Baptist Church the high degree of attention paid in the critical planning stages by them and the Dreamsound team has had the desired effect. Yonsei Central Baptist Church now stands as one of the most impressive Houses of Worship in Asia, if not the world.