4
PLACEMENT
THE BOUNDARY EFFECT
With their compact dimensions, the Niles SW8 and SW6.5 subwoofers provide a wide range of
placement options, including wall or ceiling mounting via an optional mount kit.
When considering where to place a subwoofer in a particular space, note that the “boundary
effect” can provide increased acoustic output due to the reinforcement effects when the subwoofer
is placed on the floor, by a wall or in a corner.
Generally, when placed in or near a corner, the acoustic output of the subwoofer is substantially
greater due to the boundary effect’s acoustic gain. This provides two benefits. First, as the acoustic
output of the sub (as perceived at the prime listening position) is greater than in free-space (away
from the walls, floor and ceiling), the subwoofer doesn’t need to “work” as hard, which results
in lower distortion. Second, the gain provided by the boundary effect serves to increase the
subwoofer’s available dynamic range, for increased deep bass output at elevated listening levels.
Generally, corner placement provides the greatest acoustic reinforcement. However, corner
placement is not always optimum, and some experimentation may be necessary in any particular
room.
If the subwoofer is placed far away from the main speakers, there may be an audible discontinuity
between the low bass sound from the sub and the wider upper range sound from the main
speakers. This becomes even more critical when using compact main speakers, where a higher
crossover frequency is often necessary. At a high crossover frequency (150 Hz), there is a much
greater chance of audible main speakers and subwoofer discontinuity, with the subwoofer’s output
becoming distinctly audible as a sound source.
Ideally, the best subwoofer placement in any given space will reward the listener with a high
quality full range acoustic experience, with the subwoofer itself seamlessly blending in with the
main speakers, and not audible as a sound source itself.
