d&b TI 385 d&b Line array design - Manual (Page 13)

7. The xA-Series line array
The 10AL and 10AL-D line array modules of the xA-Series
have been specifically designed for fixed installations with
visually unobtrusive integrated rigging systems.
For these applications, the cabinets are available with two
different constant directivity dispersion characteristics in the
horizontal plane:
The 10AL provides a 75° coverage while the 10AL-D
version provides 105° of coverage. In the coupling plane,
both allow for vertical splay angles of up to 15° per
cabinet. Both versions may be combined in one array, for
example with 10AL cabinets at the top for longer distances
and one or two 10AL-D to cover the areas near the stage.
Both systems can be used from small configurations of three
cabinets per array up to a maximum of 9 cabinets per
array.
The 10AL (-D) covers the frequency range from 60 Hz to
18 kHz. 18A-SUB or 27A-SUB subwoofers extend the
system bandwidth down to 37 Hz or 40 Hz, respectively.
They can be flown in a separate column, integrated at the
top or within an array or used as ground stacked
applications. When they are flown together with line array
modules, the maximum number of total cabinets is reduced
due to the additional weight.
Configurations of up to six 10AL / 10AL-D cabinets can
also be used ground stacked, supported by 18S-SUB or
27S-SUB cabinets. The most even energy distribution in the
audience area will however be achieved with a flown
array.
7.1 Number of cabinets required
The number of 10AL or 10AL-D cabinets to be used in one
application depends on the desired level, the distances to
be covered and the directivity requirements of the particular
venue. Using the d&b ArrayCalc calculator will prove
whether the system is able to fulfill the requirements.
Depending on the program material and the desired level
additional 18A-SUB or 27A-SUB subwoofer systems may
be necessary to extend the system bandwidth and
headroom. The number of subwoofers required per 10AL
(-D) cabinet to provide a serious full-range program
decreases with the size of the system. For small to medium
size setups, a 1:3 ratio is recommended, for example one
27A-SUB to three 10ALs.
7.2 Subwoofer setup
When used with subwoofers, the 10AL(-D) systems should
be operated in CUT mode to gain maximum headroom at
low frequencies.
27A-SUB/27S-SUB (40 – 100/140 Hz)
Subwoofers can be used to supplement the LF headroom of
the 10AL loudspeakers in various combinations.
To achieve the best acoustic result in critical venues, we
recommend the use of 27A-SUB or 27S-SUB subwoofers.
They offer a compact and effective solution by providing
cardioid dispersion from a single amplifier channel.
They can be used ground stacked (27S-SUB and 27A-SUB)
or integrated into the flown array (27A-SUB), either at the
top or within a 10AL array, or flown as a separate column.
Flown subwoofers create a different level distribution in the
audience area than ground stacked ones. Particularly the
area directly at the front below the arrays provides less low
frequency energy when subwoofers are included in the
array.
This can be very useful in applications that do not require
high levels of low frequency energy at the front, however
for an event requiring a loud stage level, additional ground
stacked subwoofers may be necessary.
For 10AL arrays consisting of three or more cabinets, we
recommend the use of the 100 Hz setting for the
subwoofers. Smaller 10AL arrays providing less coupling at
low frequencies may benefit from the higher crossover
frequency of the standard mode (140 Hz).
10AL / 18A/27A-SUB crossover setup
18A-SUB/18S-SUB (37 – 100/140 Hz)
18A-SUB or 18S-SUB cabinets can be used in the same
way as 27A-SUB or 27S-SUB cabinets but without the
benefit of cardioid dispersion.
For these systems, just like for the 27S/A-SUBs, a 100 Hz
circuit is available on the controller, which can be set
accordingly.
TI 385 (6.0 EN) d&b Line array design, ArrayCalc V8.x Page 13 of 54