Hawkins Bass Control - Theorv and Use
INSTALLATION STEP 1
Hawkins Bass Control (variable) is a unique subwoofer control circuit included with the Soundstream RUBICON amplifier. It is capable of removing subsonic energy in program material be- low 45 Hz at 12 dB/Octave, while boosting subwoofer frequen- cies. The circuit consists of two controls. One engages a sub- sonic High Pass filter at 45 Hz, and the other adjusts the amount of boost (0 to +9 dB) (fixed at +6dB for the RUBCON & 355).
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 fre- quencies can improve system output by as much as 3 dB.
HAWKINS
BOCST
Q
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c’0 ;
FIG, 1
SELECTING THE SPEAKER OUTPUT MODE
Channels 1 through 4 of the RUBICON255, 355 & 555 amplifiers have the ability to operate in any one of the following modes:
5CH (Stereo /Mixed Mono): Use this mode for 5 channel stereo operation (all channels) or for Mixed Mono operation_
3CH (Bridged Mono): Use this mode to bridge channels l&2 and 3&4 outputs for 3 channel operation.
Please follow the wiring schemes below for the correct operation:
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Subwoofer drivers in general have excel- lo |
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lent power handling characteristics over | 5 |
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their operational bandwidth. This bandwidth | .t |
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is determined by many factors, including |
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driver design and enclosure type. It is pos- | 15 |
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sible to overdrive any subwoofer driver by |
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sending powerful signals outside of its op- |
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erational bandwidth. These potentially dam- | :recuency (HZI | 5 0 |
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aging signals can be removed by adding a | FIG. 2 VARIABLE BOOST |
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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.
Adjustment (555 on/y)
An easy method of optimizing your existing subwoofer enclosure with Hawkins
Bass Control is as follows: | 1 0 |
c
1.Adjust the boost control to full counter 0
dB
2. Set the bass control switch to ,5
“HAWKINS BASS CONTROL”. | 20. |
3.Play moderate to loud bass material.
Frequancy ( H z ) | 5 0 | 1 0 0 | 2 3 0 | |
4. Adjust the boost (Q) control until you | FIG. 3 Limited Excursion |
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reach the desired level. |
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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.
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__~ ____._- __.____ \ |
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