Infographic – How does SIAP work?

Click on the topics below to get a short explanation of the concerning subject.


A small number of microphones (usually four) high above the front of the stage capture the sound. Feed the stage sound of the performers, orchestra, choir etc. with all of its information such as source location(s) and their tonal quality to the SIAP acoustic processor.

The SIAP processor is a very powerful sound processing “system”. In this the sound is treated with appropriate time delays, filters and reverberation fine-structure based on the desired acoustic. For this purpose the processor comprises a large number of independently digital programmable channels.

The SIAP system is very user friendly. No specialist knowledge needs to be at hand to operate the SIAP system. Simply choose between the acoustic presets (even wireless), for example: (unamplified) speech as in drama, operetta/light opera, grand opera/classical ballet, chamber music, non-classical unamplified ensemble, chamber orchestra, large orchestra, choir/vocal group. Changing between (movie) surround presets and users presets are just as easily.

The output from the processor generates a "sound blanket" that covers the entire room (and orchestra pit and /or stage). This sound field, that is exactly the same as the reverberation time and corresponding nuances as set in the processor software, forms the optimum acoustic together with the hall itself. The SIAP system creates this sound field by building up reflections, reverberation etc. in exactly the same way as the natural reflections and reverberation in a hall itself, while keeping the orginal acoustic character "signature" of the room.

This sound is reproduced in the hall through high quality power amplifiers and about 50 to 200 loudspeakers, distributed over the walls and ceiling. All of these individual loudspeakers contribute for one or two percent of the total contribution which makes each loudspeaker individually unnoticeable to locate.

SIAP’s natural process preserves the natural balance, the correct localization and the timbre of the sound sources on stage (instruments, singers, actors). With a SIAP system a spectator can close his/her eyes and still localize the source position, which then appears to be exactly correct when the eyes are openend again. Of course the same correct localization correctness applies to sound sources moving around the stage area (walking singer, actor or musician). At SIAP demonstrations this is always a nice experience.

Ofcourse we are (more than) aware of all cosmetical and architectural aspects in the halls. We always respect the architectonic elements in a hall and adjust our loudspeakers in the desired color(s) so that they will “blend” and fit in the design of the hall.

A visualisation of the SIAP system is shown in the infographic on the right site.