SIAP is unique among electronic acoustic systems:

SIAP-reverberation – is real reverberation. The generated reverberation consists of in a natural way (digitally) made reflections. The reverberation as generated by the system is built up from sound reflections as these are present in natural acoustics. Each reflection is individually generated by the SIAP processor; so it is not a repeat of a preceding one with some adjustments. For filling in the missing reflections in a hall’s acoustic the SIAP processor has a large number of independent channels at its disposal, each with its own reflection pattern tailored to the needs of the hall. The SIAP loudspeakers each reproduce complete reflection patterns: early and late reflections together form one “enveloping” acoustic. There are no dedicated loudspeakers for only early reflections and others dedicated to reverberation, as this would be contradictory to what is the case on a natural acoustic.

SIAP has full control – over its process. For example, the reverberation time as set in the processor in each preset is equal to the desired reverberation time in the hall for the specific purpose of use. For example, a reverberation time o 2 seconds in the processor (the optimum for symphonic music), means that the measured reverberation time in the hall is that same 2 seconds. In other words, SIAP has full control over the enhanced acoustic of the hall. This way the SIAP system fills in the missing reflections for each specific use (speech, chamber music, orchestra, choir etc.) which, together with the auditorium’s natural reflections from walls, ceiling, floor etc. lead to the desired acoustic.

SIAP’s process – creates one overall acoustic, as a result of which the additional reverberation does not sound like an “effect”. To say it differently, the unique character of the hall is preserved, while the acoustic is made optimal for the current use of the day. The auditorium’s acoustic and the SIAP addition seamlessly work together to become one. The SIAP system completes the acoustic, does not superimpose a complete (artificial) acoustic on top of the hall’s existing natural acoustic. A further advantage of this working principle is that the existing acoustic of the hall do not have to be altered or made suitable for implementation of a SIAP system.

SIAP does not use recirculation – of auditorium reverberation in the system. After all, such recirculation is not present in natural acoustics and would lead to unwanted coloration – a metallic sounding decay. Thanks to the absence of recirculation the acoustic with SIAP is not influenced audibly by the hall’s occupancy (with or without audience).

SIAP creates time-constant reverberation – so that no pitch fluctuations, wow etc. can occur in the acoustic. Time-constant means that SIAP is inherently “piano-compatible”; the same is true for any other musical instrument and for the human voice. This contrary to systems which seek refuge to time variance, whereby the produced “reflections” are floating in time around a basic pitch (continuously changing pitch). Herewith a larger number of reflections is suggested than there in reality are; the main purpose of time variation is to limit acoustic feedback in order to prevent the system becoming unstable (howl round). Time variance leads to a howling decay of instrument strings (audible interference with the natural string sound decay) and to a blurry reverberation sound. Furthermore the shape and dimensions of the hall are continuously changing during while the music plays.

These are highly undesirable artefacts of such processes. Of course in a natural acoustic the sound reflections do not have variable, on the contrary they have constant delay times, determined by the shape of the hall (length, width, height, diffusing surfaces, decoration, sound absorption of the materials etc.). As SIAP is time-constant, the system preserves the clarity and definition of the sound that is characteristic for good concert halls. And there is no risk of floating pitch decays of – for example – piano strings which have their own decay behavior. Self-evidently SIAP has sounds natural for people with “absolute-pitch-hearing”. For pianists, piano tuners etc. SIAP does not have to be switched off. For these obvious reasons no time-variation is present in a natural acoustic. Musicians and other critical listeners appear to be very sensitive for this.

SIAP’s natural process – preserves the natural balance, correct localization and sound colour (timbre) of the sources on stage (and in the auditorium):instruments, singers, actors).