Hawkins Bass Control - Theory And Use - Soundstream Rubicon 1002 Owner's Manual And Installation Manual

Hawkins Bass Control - Theory and Use (302)

Hawkins Bass Control (variable) is a unique subwoofer control circuit in-
cluded with the Soundstream RUBICON amplifiers. It is capable of re-
moving subsonic energy in program material below 45 Hz
at 12 dB/Octave, while boosting subwoofer frequencies. The
circuit consists of two controls. One engages a subsonic
High Pass filter at 45 Hz, and the other adjusts the amount
of boost from 0 to +9 dB.
The Boost control adjusts the amount of level applied at
the set frequency, and is adjustable from 0 to +9 dB (see
figure 2). When the boost is set to 0, Hawkins Bass Control
acts as a sub sonic filter only. The simple act of removing
potentially harmful low frequencies can improve system out-
put by as much as 3 dB.
Application
Subwoofer drivers in general have excel-
lent power handling characteristics over
their operational bandwidth. This band-
width is determined by many factors, in- dB_10
It is possible to overdrive any subwoofer -20
driver by sending powerful signals outside
of its operational bandwidth. These po-
tentially damaging signals can be removed
by adding a subsonic filter. Figure 3 shows the effectiveness of the Hawkins
Bass Control on woofer excursion in a vented enclosure. The woofer travels
7.5 mm at 10 Hz. With Hawkins Bass Control properly adjusted, this excur-
sion can be reduced to less than 1 mm. This is of great benefit to lowering
woofer distortion and increasing output.
Adjustment
An easy method of optimizing your existing subwoofer enclosure with
1. Adjust the boost control to full
counter clock-wise (0) position.
2. Set the bass control switch to
"HAWKINS BASS CONTROL".
3. Play moderate to loud bass mate-
rial.
4. Adjust the boost (Q) control until
you reach the desired level.
FIG. 2 VARIABLE BOOST
FIG. 3 Limited Excursion
11
I IllIll
HAWKINS
SUB
BASS
l
SONIC
CONTROL
HAWKINS
BASS
CONTROL
Q
FIG. 1
50 100 200