Q Acoustics 2000i Serie Manual De Usuario página 17

Connecting the 2070Si
Stereo System
Setting Up
Always bear in mind that the human ear's sensitivity to bass varies
enormously with the volume level, hence the need for a wide range of
programme material and sound levels. Once you are happy with the
sound you can then fine tune the performance by using the remaining
controls.
Crossover: The crossover control determines at what frequency your
sub-woofer output begins to rapidly diminish. This should be set so that it
corresponds with the frequency your main speakers begin to produce a
strong output by themselves. The adjustment allows for a smooth
handing over between sub-woofer and main speaker output. If this
setting is too low there will be a 'hole' in the sound where certain
frequencies are weak, conversely if it is too high there will be an
exaggeration of certain frequencies producing an overpowering bass.
You can get an idea of the correct setting from your main speakers
specification sheet, look for the lowest frequency that the speaker
produces (the "-3dB point") under the "Frequency response" heading.
Room positioning has a dramatic effect on low frequency reproduction
of both the sub-woofer and your main speakers so don't be worried if you
find you require a setting which does not correlate with the specified low
frequency point of your main speakers.
Setting up can take many hours of listening because all of the controls on
your subwoofer will interact; there is no easy route to success. The best
phase invert switch position is strongly affected by the chosen crossover
frequency so as you fine tune the controls you may wish to keep trying
the alternative setting to see which you prefer.
Once you feel you are close with the settings you can now perfect the
integration between sub-woofer and main speakers by adjusting the
phase control. This control is unique in that it uses a pure delay, made
possible by the integrated Digital Signal Processor, and so does not add
sound damaging "group delay" as with most sub-woofers. The DSP
scales the available delay so that this control always provides a 0 – 180°
phase shift at the chosen crossover frequency. This control affects the
level of bass produced at the crossover frequency and also how
smoothly the transition occurs. Again this will interact with the crossover
control so fine adjustments of the crossover frequency may be
necessary to produce the best results. Also you may find you can get to a
better end result by flipping the phase invert switch and trying to optimise
the crossover and phase controls again. Experimentation is the key to
getting perfect integration; once this is achieved you should never be
aware of any sound coming from the direction of the sub-woofer itself.
The end result will be a system with powerful, extended bass response
which appears to be coming from the soundstage between the main
speakers.