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C3 Data Sheet C3

-5

100 1k 10k

20k

Typical change in frequency response when

decreasing the splay angle between two

cabinets from 5° to 2.5° and 1°.

2.5

Longest

C3 column

in array

Low shelf

Gain

3 800 Hz –3

4 600 Hz –4

5 450 Hz –5

6 350 Hz –6

7 250 Hz –7

8 200 Hz –8

Single column

This typical 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 on the left; the gain listed applies to a single column. This

equalization has to be used for the C3s only. C4-TOP cabinets in the

array should be driven from a separate signal.

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

compensate for air absorption effects when covering remote

audience areas. In opposite to the HFC circuit of the controller this

“mechanical HFC” equalization 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.

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.

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.

The configuration of any array should be thoroughly adapted to the

actual venue room acoustics and requirements. In order to keep

diffuse sound low, the total coverage angle should only be as wide

as necessary to cover the audience area.

Operation with C4-SUB and B2-SUB

To extend the C3 frequency response C4-SUBs should be used.

Forming columns of SUB cabinets improves efficiency and vertical

directivity at low frequencies.

For a balanced sound at high levels a ratio of at least one C4-SUB

per C3 or C4-TOP cabinet is required.

For a further extension of bandwidth and headroom ground stacked

B2 subwoofers are used (INFRA mode).