RCF P Series, Инструкция по применению

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P SERIES
3.6 Natural and Artificial Echoes
Outdoors, it’s common for sound to be reflected by a wall or a building. If a listener hears a single reflection 50
milliseconds or more after the direct sound, he will perceive it as an annoying echo that reduces intelligibility.
It’s possible also to perceive an “artificial echo” by separating two loudspeakers so that a listener hears the second
loudspeaker at least 50 milliseconds after they hear the first loudspeaker. There’s no reflection here but the effect is
the same as an unwanted echo.
To avoid natural echoes, try to aim loudspeakers away from walls or buildings. To avoid artificial echoes, use a point
source or distributed design as illustrated in this Application Guide. When it’s necessary to split the loudspeakers,
try to avoid overlapping coverage, each listener should hear only one loudspeaker.
Imagine an outdoor system at a sports facility where the announcer is located 11 m or more from the loudspeakers.
The announcer will hear his or her own voice. Then, about 35 milliseconds later, the announcer will hear his/her
own voice again as an echo! Although a broadcast professional or other trained announcer may be able to ignore
this echo, most people find it difficult to speak in this situation. To minimize the problem, the announcer should
stay in a closed room. Alternatively, give the announcer a local monitor loudspeaker or a set of headphones so he/
she can hear their own voice strongly. This masks the echo and minimizes the nuisance.
3.7 Notes on placement
In many cases P series speakers are installed in large environments, either indoor or outdoors, quite often highly
reverberant. A distributed system design, where speakers are placed homogeneously (for example hanging from
the roof) and each part of the audience is kept as close as possible to a loudspeaker, is usually the better way to
maintain good intelligibility even in environments with bad acoustic features. In a distributed system it’s important
not to overlap the areas that are covered from different speakers to avoid artificial echoes as discussed above.
If the speakers are placed as remote repeaters of sound coming, for example, from a main stage, it’s highly
recommended to compensate for the different path with a properly configured delay device.
In some cases a system design based on large central clusters is preferred due to scarcity of rigging points or for
ease of installation, in this case it’s recommended
to correctly direct the speakers towards the audience avoiding walls or ceilings and to avoid overlaps as much as
possible. For correct cluster configurations the following tables may help you.