Void Arcline 212, Руководство пользователя

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Arcline 8/212 User Guide V1.0 Page 55
Figure A.10: Flown and curved 24-cabinet (6.84 m) Arcline 8 array showing good low-mid – high-mid spectral balance vs distance
(red = 315 Hz oct, blue = 3.15 kHz oct)
The 24-cabinet array is long enough for the low mid directivity to match the required mid/HF
coverage of the array.
As a rule of thumb, arrays that are 4.5% (minimum) to 7% the length of the flat-field distance to
be covered tend to provide good spectral balance over the vocal range. Section 7.2 for Arcline
8 array length suggestions.
Note: the above examples include some high-mid frequency air absorption, hence the slight
drop in the 3.15 kHz (blue) traces at higher distances from the array. See later for information
about air absorption.
Broadband coverage level
The length of an array also affects the overall system level. A contiguous, straight vertical array
– one that acts as a uniform line source - will provide an additional 6 dB of sound pressure
towards the furthest coverage distance every time you double its length.
Figure A.11: 6 (1.71 m), 12 (3.42 m) & 24 (6.84 m)-cabinet straight Arcline 8
arrays showing achievable broadband levels vs distance
There is less than 6 dB sound pressure level increase per doubling of cabinets nearer to
the array because the audience’s ear heights will be below the upper cabinets’ mid to high
frequency coverage patterns at the front.
(Greater summation is available for audience members further back as they’ll be within the
coverage pattern of more cabinets.)
11 Appendix A - Line array basics