L-Acoustics V-DOSC, Operator'S Manual

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L-ACOUSTICS V-DOSC Manual Version 4 6/29/2005 Page 13 of 158
Figure 2: Wavefront Sculpture Technology Conditions 1 and 2 Illustrated
Additional conditions were published in the Audio Engineering Society journal paper ''Wavefront
Sculpture Technology'', JAES Vol. 51, No. 10, October 2003. The first two WST conditions were re-
derived (based on an intuitive approach using Fresnel analysis) and in addition it was shown that:
3) Deviation from the ideal, target wavefront (flat or curved) radiated by individual sources of the array
must be less than a quarter wavelength at the highest operating frequency (this corresponds to less than 5
mm of variation at 16 kHz)
4) For curved arrays, enclosure site angles should vary in inverse proportion to the listener distance
(geometrically this is equivalent to shaping variable curvature arrays to provide equal spacing of individual
enclosure site angle impacts on the audience listening plane)
5) Limits exist concerning the vertical height of each enclosure, the minimum allowed listener distance and
the angles that are allowed between enclosures.
The key to satisfying WST conditions at higher frequencies is a proprietary L-ACOUSTICS waveguide
that is used to load a conventional compression driver. This DOSC
®
waveguide was invented by Dr.
Christian Heil and is patented world-wide (see Appendix 4). DOSC stands for ”Diffuseur d’Onde
Sonore Cylindrique” – in English this means Cylindrical Sound Wave Generator (note: the “V” in V-
DOSC refers to the V-shaped acoustic lens configuration employed for the mid section). Essentially,
the DOSC waveguide permits fulfillment of the 1
st
and 3
rd
WST conditions at higher frequencies.