Preference Audio P-1200 - Manual (Page 8)

8 O W N E R ’ S M A N U A L
P-1200
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 P-1200 controls will allow you to make the best of virtually any
installation. If you feel uncomfortable with setting up your P-1200 after reading through this section then
you should consider enlisting the help of an experienced person or contacting your dealer.
Below are a few generalized rules for understanding the acoustic nature of low frequency sound
reproduction in an average residential listening room. These rules will aid in understanding the best
placement of and tuning of your P-1200 subwoofer. If possible, experiment with the placement of your
P-1200 to determine what works best in your listening room.
Virtually all rooms have significant resonant modes. The listener will experience these resonant
modes as an acoustic increase or decrease in intensity at certain frequencies. These resonant
modes are a result of reflected acoustic energy within the room interacting with other acoustic
energy, either reflected or direct. These frequency dependent nodes or antinodes, as they
are called, are different for every listening position within the room. Equalization cannot
simultaneously compensate for all locations within a room. Only physical elements within or
at the room’s boundaries can effectively alter the room’s behavior. These resonant modes can
produce large errors in the frequency response and reduce the overall enjoyment of the audio
reproduction. Subwoofer placement has some effect on the location of the resonant modes. One
should contact an expert in the field of acoustics if one finds that the low frequency reproduction
in their room is unsatisfactory.
Placing the subwoofer near a wall will substantially increase its effective radiating power, especially
at very low frequencies. Placing the subwoofer near the intersection of two walls
(a corner) will substantially increase it even more. Corner loading, as it is called, is an excellent
way to get bass extension and greater acoustic output from your subwoofer and can increase the
listening pleasure.
Placing the subwoofer close to the listening/sitting position will increase the intensity of the
transients and reduce the acoustic power demands from the subwoofer. The listener will hear
more direct sound from the subwoofer and less reflected sound.
Bass frequencies are generally 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 the
case. There are cues such as tactile vibration and higher frequency signal components that can
suggest the direction of the source. For this reason it may be desirable to locate the subwoofer at
the front of the room near the main speakers. It may also be necessary to reduce the crossover
frequency if one finds that the bass sounds too detached from the other sound sources.
If placement of the woofer at the front of the room is not an option, consider placing the
subwoofer at the back of the room. Placement directly behind the listening position can produce
very good results as well as corner loading in the back of the room.
Using multiple woofers at opposite corners of the room can be done to balance the localization of
the sound.
It is not necessary to direct the front of the subwoofer at the listening position.
The vent at the back of the enclosure must not be blocked. It is advisable to leave at least 3 to 6
inches of space behind the vent. If necessary, turn the cabinet so that the back of the subwoofer
does not back up directly to a wall.