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
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
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.
