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S E T U P
Placement
There are a number of factors, both acoustic and aesthetic, that ultimately determine the best loudspeaker
placement. Subwoofers, by nature of the frequency range in which they operate, have their own challenges,
which have as much to do with the room acoustics and listening position as anything else. In many cases the
designated location may already be chosen and the only available adjustments may be the subwoofer's controls.
The PS-12 controls will allow you to make the best of virtually any installation. If you feel uncomfortable with
setting up your PS-12 after reading through this section then you should consider enlisting the help of an
experienced person or contacting your dealer.
Below are a some generalized rules for understanding the acoustic nature of low frequency sound reproduction in
an average residential listening room. These rules will aid in the placement and tuning of your PS-12 subwoofer.
If possible, experiment with the placement of your PS-12 to determine what works best in your listening room.
Most rooms have significant resonant modes at low frequencies. The listener will experience these resonant
modes as a variation in the intensity of certain frequencies at different locations within the room. Resonant
modes are the result of reflected acoustic energy interacting within a room's boundaries. The resonant modes
can produce large errors in the frequency response and reduce the overall enjoyment of the audio reproduction.
Equalization cannot simultaneously compensate for all locations within a room. However, physical elements
within or at the room's boundaries can effectively improve the room's behavior. Subwoofer placement also has
an effect on the excitation of the resonant modes and the way they are experienced. Contacting an expert
in the field of acoustics can be worthwhile if one finds that the low frequency reproduction in their room is
unsatisfactory or if one wants assistance in optimizing their installation.
Placing a subwoofer on the floor near a wall will increase its radiating power by as much as 2X. Placing a
subwoofer on the floor near the intersection of two walls (a corner) will increase its radiating power by as much
as 4X. Corner loading, as it is sometimes called, is an excellent way to get bass extension and greater acoustic
output from a subwoofer especially at very low frequencies.
In the same way that the subwoofer's output is augmented by a corner, the listening position can also have a
significant effect on how the bass is experienced. Sitting at a room's boundary, such as near the back wall of a
room, will significantly increase the bass level across much of the low frequency spectrum.
Placing a subwoofer close to the listening position (less than 5ft (1.5m)) can increase the intensity of the
transients and reduce the acoustic power demands from the subwoofer in some installations. In others, it can
increase the power demands if the woofer is placed at a primary node. Placing a subwoofer(s) close to the
listening position can also create more tactile sensation.
Bass frequencies below about 80Hz are considered to be omnidirectional and tend to have no localization. That
is to say that it is difficult to determine their place of origin. For this reason, placement of most subwoofers is
not limited to the front of the room. However, in practice this is not always the case. There are cues such as
tactile and audible vibration and higher frequency signal content that can suggest the direction of the source.
For this reason it may be desirable to locate the subwoofer(s) at the front of the room. It may also be necessary
to reduce the crossover frequency below 80Hz if one finds that the bass sounds too detached from the other
sound sources.
Placing a subwoofer(s) at the back of the room is also a consideration especially if placement of a subwoofer at
the front of the room is not suitable or produces poor results. Placement directly behind or beside the listening
position can produce very good results as well as corner loading in the back of the room. Other options include
placing the subwoofer(s) on the side(s) of the room especially when multiple woofers are used. If possible
experiment with different positions. Don't exclude the possibilities of locating your subwoofer in walls, ceilings,
floors, or underneath, beside, and behind furniture.
Symmetrically or asymmetrically locating two or more woofers in the room can be done to reduce room mode
effects and to balance the localization of the sound.
It is not necessary to direct the front of a subwoofer at the listening position.
PS-12
O W N E R ' S M A N U A L
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