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Lift the loudspeaker enclosure into the hole and
turn the Phillips 2 screws on the front baffle
clockwise so that the mounting tabs rotate out-
wards. Continue tightening the screws until the
sheetrock is firmly clamped between the mount-
ing tabs and the enclosure flange. If necessary,
a secondary support line can be attached to the
tab next to the loudspeaker cable connector.
4
The Room Response Controls
Because all loudspeakers have different responses depending on where they are placed within different
rooms, flexible room response controls have been integrated into the design to help optimise the loud-
speaker's tonal characteristics once they are installed.
4.1
Boundary Loading Effect
The sound produced by a loudspeaker in a room is limited by the large reflecting surfaces of that room. For
low frequencies this means the walls, the floor and the ceiling. Here, the room effects are the strongest.
In the midrange, mainly the loudspeaker enclosure and objects near the loudspeaker limit the radiated
sound. For high frequencies, the sound is limited entirely by the loudspeaker baffle and the driver itself.
Low frequency sound spreads out in all directions (omnidirectional) for all loudspeakers and subwoofers
so cancellations, standing waves and the proximity of boundaries affect their performance. As an exam-
ple, loudspeakers typically have a flat free field response (anechoic response in 4π space) so mounting it
in a large wall corresponds to limiting the radiation space to a half what it was when the loudspeaker was
designed. This gives a 6 dB increase at frequencies below, say, 200 Hz. This applies to any flush mounted
loudspeaker or loudspeakers placed with their back against a solid wall. Placing the same loudspeaker
in a corner (intersection of two walls but not on the floor), results in a low frequency increase of 12 dB.
An increase of 18 dB is seen for positioning in a three-walled corner. For subwoofers, which are usually
located on the floor against solid wall, a 12 dB increase is seen compared to free field acoustic condi-
tions. Once placed in a corner the increase again will be 18 dB. This gain is beneficial for subwoofers, as
it provides additional headroom and a consequently lower system distortion.
The boosts mentioned above are theoretical and for an ideally simple situation. Experience shows, for
example, that the actual low frequency emphasis when placing a loudspeaker next to a wall is generally
about 4 dB. In all cases, this boost has to be compensated otherwise a natural sound balance will not
be heard. This is achieved by using the unique Genelec Room Response Controls featured on all Home
Theater loudspeaker models.
4.2
'Tuning' the Home Theater
4.2.1
Subwoofer Phase
Setting the phase of the subwoofer(s) is essential for a good sounding Home Theater. If the phase is not
correctly set, then adding subwoofers can actually result in LESS bass in the listening area. There are
four ways to achieve a good result but only use one subwoofer for these procedures then set the other
subwoofers to the same setting when the result is known:
Test Tone
Instructions for setting the subwoofer phase using a test tone are detailed in the 5050A, HTS3B
and HTS4B operating manuals, so they have not been repeated here.
26
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