Boston Acoustics HSi Series GT-475 - Manual (Page 10)

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10
Tuning The Amplifier - Front Speakers and Subwoofer (s)
1) Front Signal Routing Switch
If using two sets of RCAs (independent front and rear RCAs), set the switch to DEDICATED FRONT AND REAR
INPUTS . If you are using one set of RCAs for both front and rear channels, set the switch to SEND FRONT
RCA SIGNAL TO REAR. (refer to the diagram on page 5).
2) Head Unit
The head unit should have all controls such as bass, treble, balance, and fader set to the flat or centered
position. The volume control should be at the minimum setting. If the head unit has any equalization or bass
management features such as boost, they should be deactivated at this time. Turn head unit on, and verify
that the RED status LED (logo) is illuminated on the amplifier.
3) Volume
With the chosen musical track playing, turn the head unit volume control up until the maximum level of
undistorted signal is heard from the speakers. For most head units, this will be at the end of the volume
control range.
WARNING! A distorted signal from the head unit sent to the amplifier can cause speaker failure at higher
listening levels.
4) Input Sensitivity Control (Front and Rear Channels)
Turn control (refer to the diagram on page 5) all the way counterclockwise (minimum position). In this
position, the amplifier will be less sensitive to the input signal from the head unit. Slowly rotate this control
clockwise until maximum undistorted playing level is heard from the subwoofer(s). Listen closely for faults
such as bottoming from the subwoofer(s). If fault is detected, rotate input sensitivity control counterclockwise
until fault is eliminated. At this point, the maximum undistorted subwoofer playing level has been defined.
5) Highpass Crossover Control (Front Channel Only)
To achieve higher undistorted playing levels from the front speakers, the highpass crossover must be
engaged. Rotate the crossover control fully clockwise (refer to the diagram on page 5). The highpass
crossover point is now set at 350Hz. Rotate “Q-Tune™” Control fully counterclockwise. Move crossover
switch to the right (ON) position.
Bridged Lowpass with Q-Tune ™ Switch Configuration Diagram