ATL twotwo sub1, Руководство пользователя

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With their unique
TM
Advanced Transmission Line
cabinet design, ultra-low distortion, and smooth bass roll-off, PMC loudspeakers are
more forgiving of difficult room conditions and placement constraints than conventional designs. However,
we encourage you to spend some time experimenting in your own room to achieve the very best results,
remembering that small changes in location can often influence system performance significantly. The
following guidelines are suggestions for a starting point to locate your new subwoofer and optimise its
alignment. Fine-tuning can start from there.
Positioning
Since the
twotwo
active subwoofers reproduce frequencies below 150Hz, they don’t contribute information
towards stereo imaging, and can therefore be placed independently of the main satellite stereo
loudspeakers. However, the ideal positioning will be affected by the nature of the room’s standing waves.
A simple way of finding the optimal location for the subwoofer is to place it initially at the listening position.
Play music or test signals with wide ranging bass notes and move around the potential subwoofer locations
listening for the position which gives the most uniform sound with minimal boomy or weak notes. The
subwoofer can then be relocated to the most uniform position. Ideally, this will be close to the front wall
and somewhere between the two front speakers, but not on the exact centre line.
Alignment
Once the optimal location has been decided, the subwoofer’s electrical alignment can be performed.
The first parameter to adjust is the low-pass filter frequency and roll-off. These should complement the
satellite speaker’s low-frequency roll-off.
Next, the Phase can be aligned to ensure that the subwoofer signal through the crossover region arrives
at the listening position in-phase with the satellite speakers. A test signal (sine wave tone) is required at a
frequency which will be reproduced by both the satellite speakers and subwoofer – typically around 85Hz.
The phase control (and if necessary the polarity inversion) should be adjusted to make the tone as loud as
possible, indicating proper alignment.
Finally, the level of the subwoofer can be adjusted to provide a smooth and balanced extension to the
low-frequency performance of the satellite speakers. When set correctly you will be almost unaware of
the subwoofer’s contribution, noticing its absence when switched off! If you are aware of it in normal use it
is probably turned up too loud!
Positioning & Alignment