Installation manual

Community S-Series - Operation and Installation Manual - Page 34
Second, the substantial length of low-frequency waves can make it difficult to distinguish
their source direction. This is why a single subwoofer can often be used successfully to
augment a stereo pair of mid-high loudspeakers, without unduly harming the stereo
separation and image.
Third, low-frequency waves tend to add together quite graciously, even if their sources are
separated by considerable distances, as long as they are in phase with each other. An
example of this in operation is the typical accentuation or build-up of low-frequency content
that is often experienced in the middle of theatres and concert halls, generated by
subwoofers placed far apart on the opposite sides of the stage.
Overall, the characteristics mentioned above imply that the location of a subwoofer is not
particularly critical, and to a certain extent that is true. However, there are several factors
to consider before you finalize your intended location
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. Some of these are:
(1) A subwoofer will benefit greatly in terms of power output when it’s placed adjacent to
boundary surfaces. If located at the junction of three walls, such as on the floor or
ceiling in a corner (called Eighth Space), a given subwoofer will produce a full 9dB more
output than if that same subwoofer is located in Free Space (such as when suspended
between the middle of a floor and ceiling). If located at the junction of two walls
(Quarter Space), the subwoofer will produce 6dB more output than if suspended in Free
Space. Located on a single wall, such as the floor or ceiling, the increase is 3dB. Free
Power! What could be better? See Figure 11 for additional clarification:
Figure 11: Effect of Boundary Surfaces on Power Output
When choosing subwoofer location(s), be careful, however, not to sacrifice sonic quality
for sheer power. If the available wall or corner location results in the subwoofer being
located behind, or too close, to one or more open microphones, early feedback is likely
to occur. If the wall or corner location is too far away from the full-range
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A thorough understanding of how low-frequency waves transmit in acoustical environments is very helpful when designing and
installing optimum sound systems. We recommend reading, “Fundamentals of Sound” and “Psychoacoustics” by F. Alton Everest in
the “Handbook for Sound Engineers” published by Howard Sams & Co.