Rich Natural Acoustics - AFC Improves the sound of Seocho Culture & Arts Center

Seocho Culture & Arts Center in Seoul, South Korea, is a multi-purpose arts venue which hosts lectures, theatre productions and a wide range of musical performances. A Yamaha and NEXO Active Field Control (AFC) immersive audio system has improved its acoustics for audiences and performers alike.

When it was built 30 years ago, Seocho Culture & Arts Center was designed to have little acoustic resonance, providing optimal sound for lectures and other amplified events. But it was found that the acoustics were not well suited to performances which use acoustic instruments, such as classical music.

With Yamaha Active Field Control (AFC), the acoustics of a space can be varied electronically by capturing the existing sound with microphones, processing it and re-outputting it through a dedicated speaker system. This provides a better, and infinitely flexible, experience for listeners and artists alike.

In 2013, Sound Korea Eng (SKE) was the first systems integrator to install an AFC system in the country, since when it has installed 12 AFC systems to date. The company maintains a close relationship with the Yamaha Spatial Audio Group through project design, coordination and technical support. It was the perfect choice to improve the acoustics of Seocho Culture & Arts Center by installing a Yamaha AFC solution.

AFC’s comprehensive sound space control is achieved through two functions: AFC Enhance, which controls spatial resonance, and AFC Image, which controls the positions of sound sources.

“We installed AFC Enhance at Seocho Culture & Arts Center to enable audiences to enjoy performances with a rich, natural-sounding resonance, as well as a system on the stage to give artists a pleasant sound field to perform in,” says SKE CEO Geehyoung Kim. “We also installed an AFC Image system to localise sound sources from the audience perspective.”

The system features a total of 20 microphones, comprising eight directional microphones on the stage, with four more at the proscenium. Four omnidirectional microphones are positioned in front of the auditorium, with four more at the rear.

Sound from the microphones is routed through a Yamaha R-series Rio3224-D2 I/O rack to the AFC processor, along with the outputs from a RIVAGE PM3 digital mixing system, which is used to mix performances.

From the AFC processor, audio is routed via two MRX7-D signal processors to the NEXO loudspeaker systems. These comprise 18 ID24 compact, full range speakers installed on the walls around the audience, six more as front fills and 25 more arranged above the audience in a ceiling matrix.

On the stage, eight ID24s are installed as a ceiling array, with eight P8 multi-purpose speakers installed along the stage walls. All of the ID24s are driven by seven Yamaha XMV8280-D multi-channel power amplifiers, with the P8s powered by two NEXO NXAMP 4x1s.

The AFC Image system comprises five clusters of four NEXO GEO M10 full range modules flown in a LL/L/C/R/RR configuration across the front of the proscenium, plus four MSUB 15 subwoofers. Additionally, four NEXO MSUB 18s are installed under the stage. This system is powered by four NEXO NXAMP 4x4s.

“By placing microphones in both the stage space and the audience space, we increased the number of independent channels. This ensured sufficient acoustic energy to generate optimal reverberation for acoustic music performances,” says Geehyoung Kim.

“As well as the main AFC Enhance system which covers the audience, we added an independent system for the rear of the seats, which ensures enough gain for seamless coverage throughout the auditorium.”

The AFC system is configured to add early reflections, which achieves a sense of spaciousness, an important element for acoustic music performances.

“We also included an early reflection system specifically for the stage sound field, to reinforce support for the performers. It includes returns from the audience sound field. This gives the performers the experience of a space with more natural reverb,” adds Geehyoung Kim.

“The acoustic environment of Seocho Culture & Arts Center has improved dramatically with the AFC system. In June 2024, at the venue’s 30th anniversary concert, the system received praise for its acoustics from the mayor of the Seocho district and many other local VIPs.”