L-Acoustics dV-DOSC, Руководство оператора

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dV-DOSC dV-SUB Manual V3.0 June 2005
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Figure 3: Cylindrical versus spherical wave propagation
Aside: Conventional modeling techniques cannot accurately simulate WST-based systems such as ARCS, KUDO, dV-
DOSC or V-DOSC. For WST-based products, L-ACOUSTICS has worked with the developers of EASE and CATT to
integrate proprietary SOUNDVISION modeling techniques into these industry-standard room acoustics modeling
programs. V-DOSC and dV-DOSC DLLs are available for download on: www.l-acoustics.com
When curved dV-DOSC arrays are employed there is a combination of cylindrical and spherical
propagation. This combined propagation, together with the actual shape of the audience allows the
wavefront to be focused so that tonal balance and sound pressure levels are evenly distributed
throughout the listening area. Although pure cylindrical wave propagation is not always in effect, 3 dB
reduction with doubling of distance can still be obtained along with extension of the nearfield if WST
Condition 4 is respected - this is an important aspect of WST and the reason why correct focus of dV-
DOSC on the audience is so important.
Psychoacoustically, nearfield extension allows one to walk a considerable distance from a dV-DOSC
system with only a small difference in SPL due to the system’s unconventional attenuation rate.
Effectively, more of the audience experiences nearfield listening, enjoying higher fidelity, improved
stereo imaging and exceptional clarity. Subjectively, the loudspeakers seem much closer than they are
physically and the sound is ''in your face''. This helps to improve image localization towards the action
on stage - not the loudspeaker arrays. Practically, nearfield extension also means that extreme sound
pressure levels are not required close to the system in order to obtain acceptable SPLs further back in
the venue - this is a highly desirable property that results in reduced potential for hearing loss for both
audiences and engineers alike.
Nearfield extension, combined with the precision and predictability of dV-DOSC coverage is also
effective in “pushing back” the critical distance in highly reverberant spaces (critical distance is defined
as the distance in a venue where the energy of the direct sound coming from the system is equal to
the reverberant energy coming from the room). In many situations, it is extremely important to keep
energy off the roof, for example in arenas or covered outdoor amphitheatres (sheds). If we can excite
less of the reverberant energy in the room and focus more energy on the audience, we can effectively
move back the critical distance while offering more of the audience a nearfield listening experience.
Given the well-defined vertical coverage of dV-DOSC, the benefits of WST become immediately
obvious in comparison with conventional systems when working in difficult, reverberant rooms.
Finally, another benefit of WST is the high degree of SPL rejection obtained outside of the defined
coverage pattern. Nominally higher than 20 dB, this permits the installation of a dV-DOSC system
behind or above microphones with exceptionally high feedback immunity. Monitor engineers also
enjoy working with dV-DOSC front of house (FOH) systems since there is very little backwave on
stage - even at lower frequencies. High SPL rejection outside of the defined coverage region also
makes dV-DOSC an excellent solution in situations where environmental noise control is an issue, for
example, in situations where outdoor venues are located close to residential areas.