Dynacord COBRA-4 TOP Руководство по эксплуатации онлайн [5/16] 777822

3. SETTING UP

When providing sound reinforcement for medium-sized marquees, multi-function halls and open air events,

the question often arises as to whether the enclosures have to be flown or whether simple stacking of the

enclosures near the stage will suffice.

As a rule of thumb, the angle of incidence with regard to the most distant listener should be at least

5°, if excessive attenuation of the sound waves by the audience is to be avoided.

To project over a distance of up to 40 metres, the mid/high enclosures should therefore be at least 3 to 4

metres above the floor level of the audience area

(see fig. 05).

It is still normally possible to achieve this by simply stacking the enclosures on the stage. The mid/high

enclosures should be tilted towards the furthest third of the audience area.

The 5° criterion is satisfied by such an arrangement up to a distance of around 20 to 30 metres. Beyond that,

the sound is too severely attenuated by the audience.

Figure 05

For distances of up to 80 metres, the mid/high enclosures must be between 4 and 6 metres off the

ground if an angle of incidence of around 5° with regard to the most distant listeners is to be

achieved

(see fig. 06).

Figure 06

With an unsecured ground stack that is scarcely achievable. The mid/high enclosures must therefore be

flown from a truss.

As a result of the shallow vertical directivity of the line arrays, when the systems are flown at a height of 4 to

6 metres, the medium and high frequency ranges only become audible at a distance of 10 metres from the

stage

To provide sound reinforcement to the areas directly in front of the stage, a ‘front fill’ enclosure with an

extremely wide horizontal directivity of around 120° is therefore needed (e.g. 1 x COBRA TOP).