Project Brief

The project
The Netherlands Reformed Church of Wijk near Heusden was built in the 14th century and was severely damaged in 1944 when it was in the front line. The roof collapsed and fell through the vaulted ceiling into the church space. Rebuilding the destroyed structures began immediately and in 1949 the church could be used again. The 15th century tower restoration was completed in 1955. The church has a capacity of about 600 seats. The high quality pipe organ dates from 1972 and replaced the destroyed predecessor and dates from 1972.

Rebuilding work included a new lower ceiling to save building costs and to economize the energy consumption whilst at the same time making the indoor climate more comfortable. The downside of this was however that the acoustics became rather unfavorable due to the cubic volume reduction of about 50%. Especially organ music, choir and congregational singing suffered from the resulting dry acoustics since the remaining reverberation time had become way too short.

Our work
The need for a proper church acoustic became more and more an issue. Additionally speech intelligibility needed an upgrade in at least the rear half of the main floor and in the balcony. Replacement of the sound reinforcement loudspeakers with more effective types became apparent. SIAP designed a system which integrates acoustic enhancement and intelligible speech amplification. A number of the loudspeakers serves for both purposes and an intelligent control unit adjusts the system to speech and/or music dependent of the detected sound on the microphones during religious services.

The result
The church has now acoustics that are fully adjustable to each purpose, mainly religious services but also concerts of different kinds of music. During religious services the Reverberation Time (RT) for speech is about 1.5 second while the reverberation enhancement sound level of the selected preset (typically 2.5 or 3.0 seconds) is automatically reduced sufficiently for optimum speech intelligibility. When there is choral and/or congregational singing (with organ accompaniment) or solo organ music, the appropriate RT level is activated. Acoustic presets are available ranging from solo piano, chamber music/orchestra, choir to different styles of organ music (baroque, romantic etc.); even a convincing 5.9 second cathedral acoustic can be used. Now the quality of the organ is done justice by the SIAP acoustic in this church.

Project Details

Wijk en Aalburg

Venue Build


SIAP Inauguration

SIAP processor

Natural RT
1,5 second (with audience)



Photo impressions