O W N E R ’ S M A N U A L
AB-800 SUBWOOFER
8
There are a number of factors, both acoustic and aesthetic, that ultimately determine the best subwoofer
placement. The information in this section is intended to provide you with a better understanding of the basic
acoustic elements so that you can get the most out of your system. If you wish to try getting more from your
system after experimenting with your subwoofer placement and controls, consider enlisting the help of an
experienced person or contacting your dealer.
It is probably best to start by noting that there are a tremendous number of variables that affect the bass
character within a room. This short section touches on only the most significant ones. Knowing these will aid in
the placement and tuning of your AB-800 subwoofer.
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. These resonant modes can produce large errors in the frequency response and re-
duce the overall quality and enjoyment of the audio reproduction. Equalization cannot simultaneously compensate for all locations
within a room. Large physical elements within or at a room’s boundaries (furniture, windows, etc.) can improve a room’s behavior.
Subwoofer placement also has an effect on the excitation of the resonant modes and the way they are experienced. Therefore,
experimenting with subwoofer placement can be of great benefit.
Seating location also has a significant effect on how these modes are experienced. Just take a stroll around the room when the
system is active and listen to the variation in bass character, especially at the boundaries (against a wall and in a corner). You
should notice significantly more bass at the boundaries.
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 greater acoustic output from a subwoofer and to reduce the power demands of the woofer.
In the same way that the subwoofer’s output is augmented by a corner, the listening position is also affected. Sitting at a room’s
boundary, such as near the back wall, will increase the bass level similar to the gain associated with the subwoofer placement.
The bass character at boundaries is more linear compared to other regions within a room.
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 (a location where a particular frequency is suppressed). Placing a subwoofer(s) close to the listening
position can also create more tactile sensation.
Symmetrically or asymmetrically locating two or more woofers in the room can be done to reduce room mode effects and to bal-
ance the localization of the sound.
Bass frequencies below about 80Hz are considered to be omnidirectional and tend to have no localization, making it 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 is often beneficial 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 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 es-
pecially 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.
Note: It is not necessary to direct the front of a subwoofer at the listening position.
Finally, 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.
Placement
S E T U P
