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CROSSOVER & HAWKINS BASS CONTROL
ADJUSTMENTS
CROSSOVER
In most car audio installations, there is a tendency for
a "midbass boom." Because of their interior dimen-
sions, most cars will resonate or ring at these midbass
frequencies. If we design the system so there is re-
duced output information in this region, the final re-
sponse is very smooth and natural sounding.
The RUBICON102,202 & 302 incorporates staggered
electronic crossovers. The high and low pass portions of the crossover can be set
independent of one another.
The RUBlCON102, 202 & 302 come with a 90Hz Low Pass S.I.P. and a 45Hz
Hawkins and High Pass S.I.P. (Series In-line Package resistor network) If you are
using this amplifier in the Low Pass Configuration, you will
not need to change the S.I.P. crossover. If you are using the
amplifier in a
ration we reccomend that you
180
NA
22
use a higher frequency (150Hz)
120
NA
26
for your crossover. ln order to
receive a higher crossoverpoint,
remove the factory Low Pass/
S. 1. P. (The S.I. P. with the
dot), and the factory High Pass/Hawkins S.I. P out of
the amplifier. Place the S.1. P. with the white dot in
the socket for High Pass/Hawkins. This will give a
High Pass frequency of 15OHz. Then place the re-
maining S.I.P, in the Low Pass socket. Make Sure
That the Low Pass Crossover is NOT Engaged
while the High Pass crossover is engaged! If you
want to use a frequency other than the factory pre-
set frequencies follow the chart to the left or the for-
mula below to select your own crossover points.
Pass
configu-
swap
S.I.P.
Hawkins Bass Control - Theorv and
Hawkins Bass Control (variable) is a unique subwoofer con-
trol circuit included with the Soundstream RUBICON & 302
amplifiers.
It is capable of removing subsonic energy in pro-
gram 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(+GdB for the
RUBCON102). The Hawkins Bass Control functions on either
pair of channels (l&2 or 3&4) if their low pass filter is engaged.
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 im-
prove system output by as much as 3 dB,
Application
Subwoofer drivers in general have excellent
power handling characteristics over their
operational bandwidth. This bandwidth is de-
termined by many factors, including driver
design, and enclosure type. It is possible to
overdrive any subwoofer driver by sending powerful signals outside of its opera-
tional bandwidth. These potentially 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 excursion can be reduced to less
than 1 mm. This is of
great benefit to lowering woofer distortion and increasing
output.
Adiustment
An-easy method of optimizing your exist-
ing subwoofer enclosure with Hawkin's
Bass Control is as follows:
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 material.
4.
Adjust the boost (Q) control until you reach the desired level.
With Soundstream's Hawkins Bass Control, the boost and frequency control can
provide the "tailoring" needed for any type of "assisted" design and any woofer in
any type of installation.
Use
HAWKINS
SUB
BASS
l
SONIC
CONTRO
FIG.
1
10
-15
-25
-3c
10 Frequency (Hz)
FIG. 2 VARIABLE BOOST
6 . 0
5.0
2.0
50
10 Frequency (Hz)
100
FIG. 3 Limited Excursion
13
L
I
200
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