Bookshelf-75/Center-75/LCR-75/LCR-55 page 8
should not call attention to themselves and should not be audible as separate sources of sound.
If the surrounds must be located close to the listeners, aiming them at the room walls or even the ceiling can help
to reduce any directional effect. As described above, this can produce a desirable result even in rooms where the
surround speakers are an adequate distance from the listeners' heads.
If the surrounds cannot be placed on a wall, try placement on tables or the floor to the sides of the main listening
position, firing up towards the ceiling. This can work very well in environments that do not allow permanent attachment
of speakers to the walls.
Some listeners prefer to use multiple pairs of surround speakers. While this is not necessary, it can provide a
broader and deeper surround effect, with better coverage in very large rooms. When using multiple pairs of surround
speakers, a symmetrical installation pattern works best. For example, if you are using two pairs of Bookshelf-75
Speakers for the surround channel, one pair could be mounted on the back wall of the room, mounted equidistant from
the back corners, with the other pair mounted on the side walls of the room, equidistant from the same back corners.
The surround channels can be installed in a wide variety of locations, but because they are usually mounted on
the walls of the room, they can be a challenge to successfully install. If you have further questions, please call us at
the M&K factory, and we will be happy to discuss them with you in detail.
SUBWOOFER
Subwoofer location for Home Theatre systems is essentially the same as for music systems. See our Subwoofer
operation manual for more details. Remember to leave 2 - 3 feet of clearance between any television and subwoofer,
unless the subwoofer is magnetically shielded.
The preferred connection for the subwoofer is a subwoofer output from the amplifier or controller. This insures
that a full bass signal is being fed to the subwoofer. If you do not have such a subwoofer output jack, connect the
subwoofer to the front Left and Right channel amplifier outputs (do not use the Center channel).
VERY IMPORTANT: When the Subwoofer is connected to the Left and Right amplifier outputs, and the
controller is in Pro-Logic mode, the switch on the Pro-Logic control unit labelled Center channel WIDE/NORMAL must
be set to the NORMAL mode. If the switch is set to the WIDE mode, the bass content of the Center channel will not
be fed to the Subwoofer, and you will lose a significant amount of bass.
8. SATELLITE/SUBWOOFER PHASING TEST
In any system using a subwoofer separate from Main speakers, a phasing test must be performed to insure good
bass blending. This test insures optimum sound in the critical bass frequencies where your Subwoofer and Main
speakers overlap.
Play a familiar CD, LP, or tape with steady, consistent bass content through your system. Listen carefully to the
"mid-bass" region of 75 - 125 Hz. This is the part of the spectrum where electric or string basses and drums
predominate. Then reverse the phase of either the subwoofer or BOTH Main speakers.
If your Subwoofer has a PHASE switch on its back panel, move it either from (+) to (—) or vice versa.
If your Subwoofer does not have a PHASE switch, it takes a bit more work. You will have to change the Positive
and Negative speaker inputs on the back of BOTH Main speakers.
You can do this at the back of both Main speakers, or at the Subwoofer's TO SPEAKERS terminals, but never
at both locations. The lead that was on the Positive (+) terminal should be switched to the Negative (—) terminal, and
vice versa. When switching speaker wires, take care to protect your amplifier. Make sure that the wires do not touch
each other when you are making the switch. As a safety measure, we suggest that you turn the amplifier off before
making the switch.
Now listen to the same musical passage as you did earlier, concentrating on the mid-bass region. If you hear
less bass, the original connection (or switch position) was correct. If you hear more bass, the new connection (or
switch) is correct.
You need to perform this test because when Main speakers are located separate from a Subwoofer, each
speaker is at a different distance from your ear. In some cases, the difference will be just enough so that the output
from the Subwoofer arrives out of phase with the output of the Satellites. When this happens, that critical mid-bass
is actually cancelled. You should re-do this test any time you move your speakers.
If you want to experiment further, move the Main speakers either towards or away from your listening position,
making changes in small increments. This will "focus" the system's sound to its optimum. When you hear the best
combination of stereo image localization and maximum impact and output in the mid-bass, you have the ideal location.
Bookshelf-75/LCR-55MkII/Center-55MkII/LCR-45