Bookshelf-75/Center-75/LCR-75/LCR-55 page 7
CENTER CHANNEL
The Center channel speaker in a Pro-Logic or AC-3 system is the most important speaker in the system. This
speaker often produces more output than the left and right speakers combined. This speaker should be of the highest
possible quality, and as similar as possible in response and radiation pattern to the left and right speakers. Three
identical speakers are best, unless the center channel is designed to work with a set of left and right speakers.
It is also important to have as much amplifier power as possible for the Center channel. As a minimum, the three
front channels should be identical in power output, but it is better if the Center channel has more. If you have less power
in the Center channel, this will be the limiting factor in the total output capability of the system when watching and
listening to video sources.
The Center channel speaker should be located as close as physically possible to the television or projection
screen, preferably just above or below the screen. If that is not possible, then just to the left or the right of the screen
may be acceptable.
If the television is not in the center of the room (or not centered between the Left and Right speakers), the Center
channel speaker should still be as close as possible to the screen -- even if it is outside the left and right speakers (such
as a TV located in a corner of the room outside the stereo spread of the left and right speakers). Good results can
be achieved in unusual configurations when the Center speaker is as close as possible to the screen.
The Left and Right front channel speakers in a Home Theatre system should be placed the same as the left and
right speakers in a stereo setup. Some listeners, however, may prefer to reduce the distance between the left and
right speakers to bring the size of the acoustic image closer to the size of the screen image.
For example, with a 25" direct-view television, you would want the speakers closer together than you would with
a 100" projector. One recommendation is to separate the speakers by 1.5 times the diagonal screen size; another
is to place the left and right speakers to create a 45 degree angle with the main listening position.
There is a great deal of latitude in this area, as it is one of personal preference (especially if you will listen to music
without video).
It is also preferred that the speakers be equidistant from the listening position. Equidistant usually means that
when the center speaker is on top of the television, the left and right speakers will sit in front of the set (they will be
farther from the wall behind the TV than the center speaker). Ideally, the speakers should be at the same height as
the screen, but it is much more important that all three speakers be at as close to each other's height as possible. If
the center is much higher or lower than the other speakers, the effect can be distracting. Angling, or toeing-in the
speakers, to aim at the listening position often improves imaging.
When using a Center channel speaker, you have extra flexibility in placing the left and right speakers, as the
Center channel speaker will tie most dialog and effects directly to the screen.
SURROUND CHANNELS
You can achieve good performance with your surround speaker placed in a wide variety of room locations. In
general, they should be either adjacent to or behind the main listening position, located higher than the listener's heads.
They can be mounted on either the side walls or on the back wall, flush to the wall, on shelves, on brackets, etc.
The goal is to achieve an enveloping sound. The surround channels should seem to come from all around you,
rather than seeming to come from behind you only or directly from a speaker.
This section discusses non-THX surround speakers. THX system requirements call for dipolar surround
speakers mounted to the sides of the listening position above the listeners' heads. See M&K's THX surround speaker
instruction manual and the THX Installation Guide for detailed instructions.
For non-THX surrounds, we recommend starting with speakers on the side walls of the room, two to three feet
above the listeners' heads, either directly adjacent to the listening position or behind it. You can aim the speakers
to fire towards each other (across the listening area), or you can aim them to fire towards the back wall at an angle.
The surround speakers should not be in front of the main listening position if possible.
If you mount the surrounds on the side wall behind the listening position, they can be aimed towards each other
or angled towards the back wall or the side wall surface directly behind them. By reflecting sound behind the listening
position, you may increase the sense of envelopment in the sound.
If you want or need to mount speakers on the back wall of the room, there are several options. You can aim them
so that they fire towards each other (so they fire along the back wall); you can aim them towards the front wall of the
room; or you can angle them so they fire toward the side walls. Symmetrical arrangements work best.
The speakers should be a minimum of a few feet away from the nearest listener. If the speaker is located too
close to a listener, its sound will become too directional and may distract that listener. Ideally, the surround speakers
Bookshelf-75/LCR-55MkII/Center-55MkII/LCR-45