L-Acoustics V-DOSC, Operator'S Manual

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L-ACOUSTICS V-DOSC Manual Version 4 6/29/2005 Page 12 of 158
Figure 1: Wavefront interference for a conventional sound reinforcement system
compared to a sculptured V-DOSC wavefront
WAVEFRONT SCULPTURE TECHNOLOGY BACKGROUND
As early as 1988, a preliminary system named "Incremental" had proven the feasibility of Wavefront
Sculpture Technology. From this experimental concept, further theoretical research was conducted
by Professor Marcel Urban and Dr. Christian Heil and findings were published in 1992 (“Sound Fields
Radiated by Multiple Sound Source Arrays”, AES #3269).
The theory that was developed defines the acoustic coupling conditions for effectively arraying
individual sound sources. Relevant parameters include: wavelength, the shape and surface area of each
source, the curvature of the wavefront radiated by each source and the source separation.
WST coupling conditions can be summarized as follows:
An assembly of individual sound sources arrayed with regular separation between the sources on a plane or
curved, continuous surface is equivalent to a single sound source having the same dimensions as the total
assembly if, and only if, one of the two following conditions is fulfilled:
1) Shape: The combined surface area of the wavefronts radiated by the individual sources of the array fills at
least 80% of the target radiating surface area (see also Condition 3)
2) Frequency: The source separation, defined as the distance between acoustic centers of the individual
sources, is smaller than half the wavelength at all frequencies over the bandwidth of operation (generally,
this criteria is satisfied at lower frequencies since wavelengths are sufficiently large)
These two conditions form the basis of Wavefront Sculpture Technology (WST).