Soundstream Technologies HRU. 2 - Manual (Page 10)

Hawkins Bass Control - Theory and Use
Hawkins Bass Control (parametric) is a unique subwoofer
control circuit included with the Soundstream Human Reign
Unleashed amplifiers. It is capable of removing subsonic energy
in program material while boosting subwoofer frequencies.
The circuit consists of two controls. One adjusts the frequency
of operation and the other adjusts the range of boost.
With both controls adjusted fully counter-clockwise, no boost
is applied and the amplifier is flat in response down to 20 Hz.
The Boost control adjusts the amount of level
applied at the set frequency.
This is adjustable from flat (0dB) to +9dB. (See
figure 2)
When the Boost is set to 0, Hawkins acts as a
sub-sonic filter only. (See figure 3) The simple
act of removing potentially harmful low
frequencies can improve system output by as
much as 3dB.(see figure 4)
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FIG. 2 VARIABLE “Q”
FIG. 3 VARIABLE HIGH PASS
FIG. 4 VARIABLE BOOST
The frequency control adjusts the
starting point of the subsonic filter. The
high pass filter has two frequency ranges.
When the bass control switch is set to
“SUBSONIC”, the high pass filter frequency
can be adjusted from 13 Hz up to a maximum
of 30 Hz. In this setting, no boost “Q” control
is available. This control is useful for setting
the lowest frequency that your subwoofer
will see (see figure 1).
When the bass control switch is set to
“HAWKINS BASS CONTROL” the high pass
filter frequency can be adjusted from 30 Hz
to a maximum of 70 Hz. In this setting, there
is an available boost control of 0 to +9dB.