Specifications

TI 323 (6.0E)
22 - 36
Table of low shelf parameters for a single column
Typical change in frequency response when decreasing
the splay angle between two cabinets from 5° to 2.5°
and 1°.
10
15
5
0
-5
20
100 1k 10k
20k
5
°
2.5
°
1
°
Typical change in frequency response
with increasing column length
(2, 3, 4, 5 and 6 deep)
10
15
5
0
-5
20
100 1k 10k
20k
2
3
4
5
6
6.2. Arraying C3 and C4 cabinets
6.2.1. Vertical array of C3 cabinets
A vertical array of C3 cabinets produces a precisely
shaped wave front following the mechanical
arrangement of the cabinets. The cutoff at the upper
and lower limits of the vertical dispersion of a C3
column is very sharp, and therefore precise aiming is
absolutely essential to address the desired audience
area. The vertical coverage angle of a single cabinet
is 5° and this defines the maximum splay angle
between adjacent cabinets in a column. This
dispersion angle is achieved above approximately 5
kHz, while lower frequencies will disperse into a wider
area creating an overlap of the coverage patterns of
the single cabinets. Therefore, directivity and the level
of lower frequencies increases with every cabinet
added to the column. Two cabinets arrayed vertically
with a 5° splay angle produce a flat frequency
response. Longer columns will therefore boost low
and low/mid frequencies according to the graph
below.
This behaviour can be compensated by using a
standard 2nd order (12 dB) low shelf filter. The corner
frequency and gain setting depend on the number of
C3 cabinets in the longest column and on the overall
array size. Typical corner frequencies are listed in the
table below; the gain listed applies to a single column.
Longest C3
column in
array
Low shelf
fc
Gain
dB
3 800 Hz –3
4 600 Hz –4
5 450 Hz –5
6 350 Hz –6
7 250 Hz –7
8 200 Hz –8
This equalization has to be used for the C3s only. C4-
TOP cabinets in the array should be driven from a
separate input signal feed. Decreasing the splay angle
to 2.5° or even 1° will also create an overlap of the
coverage patterns above 5 kHz resulting in increased
high frequency output to the main axis. This effect can
be used to scale the energy according to the distance
and to compensate for air absorption effects when
covering remote audience areas.
This mechanical HFC equalization as opposed to the
HFC circuit of the controller does not affect the
headroom of the system. To achieve a smooth level
distribution the vertical splay of a column is the first
thing to consider when designing a set up for a
specific venue. Usually the distances to the audience
that an array has to cover increase from the bottom
to the top of a column, consequently more power is
required at the top. This can be achieved by using
different vertical splay angles between cabinets in a
column, with smaller angles achieving more power
within a given vertical segment. For a smooth level
distribution over distance it is desirable to gradually
change the angle increments, e.g. 1°, –2.5°, –5° for a
4 deep column.
6.2.2. Vertical array of C3 and C4 cabinets
As their horizontal dispersion behaviour is identical,
C4-TOP and C3 cabinets can be easily combined in
one array. The larger vertical dispersion of a C4-TOP
can be used efficiently to cover the near field in front
of a C3 column. A vertical splay of 5° or 10° to the
lowest C3 is useful, depending on the total height of
the system.
6.2.3. Horizontal array of C3 and C4
cabinets
The horizontal angle between adjacent C3 and/or C4
cabinets in an array can be set to between 20° and
30°. The most even and widest energy distribution is
achieved with 30°. Smaller angles between the
cabinets will give a smaller horizontal coverage area
but will produce higher sound pressure on the centre
axis of the array.