Soundstream 1002 用户手册

 

 

HAWKINS

BASS

CONTROL

 HAWKINS 

BOOST

FIG. 1 BASS CONTROL

Hawkins Bass Control (parametric) is a unique

subwoofer control circuit included with the
Soundstream 

 702 and 1002 am-

plifiers. It is capable of removing subsonic en-

ergy in program material while boosting
subwoofer frequencies. The circuit consists of
two controls. One adjusts the frequency of op-
eration and the other adjusts the range of boost.
With both controls adjusted fully counter-clock-

wise, no boost is applied and the amplifier is flat

in response down to 20 Hz.

The frequency control (Hz) adjusts
the starting point of the subsonic fil-
ter. On the 

 and

1002, the high pass filter has two fre-

quency ranges. When the bass con-
trol switch is set to “SUB SONIC”,
the high pass filter frequency can be
adjusted from 

13 Hz up to a maxi-

mum of 30 Hz. In this setting, no
boost “Q” control is available. This

control is useful for setting the low-
est 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 ad-

justed from 30 Hz to a maximum of

70 Hz. In this setting, there is an
available boost control of 0 to 

 

 

-25

 

 

FIG. 4 VARIABLE BOOST

2 

FIG. 3 VARIABLE HIGH PASS

The Boost control adjusts the amount
of level applied at the set frequency.
This is adjustable from flat 

 to 

 (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 3 

 (see figure 4)

Application
Subwoofer drivers in general have
excellent power handling character-

istics over their operational band-

width. This bandwidth is determined
by many factors, including driver de-
sign, and enclosure type. It is pos-
sible to overdrive any subwoofer
driver by sending powerful signals

8 0

7 0

6 0

5.0

I O

0.0

50

200

FIG. 5 LIMITED EXCURSION

outside of its operational bandwidth. These potentially damaging signals
can be removed by adding a subsonic filter. Figure 5 shows the effective-
ness of the Hawkins Bass Control on woofer excursion in a vented enclo-
sure. 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
An easy method of optimizing your existing subwoofer enclosure with

 “Hz” control is as follows.

1.

Adjust frequency and boost control to full CCW position.

2.

Set the bass control switch to “HAWKINS BASS CONTROL”.

3.

While listening to music with strong bass content at a moderate level,
slowly adjust frequency control clockwise. Listen for a reduction of bass

response. Now, rotate frequency control slightly backwards. This serves

the purpose of removing the “subsonic” bass energy.

With Soundstream’s Hawkins Bass
Control, the boost and frequency con-
trol can provide virtually any combina-
tion of boost and cut to suit your de-
signs. So, Hawkins Bass Control can

provide the “tailoring” needed for any

type of “assisted” design and any
woofer in any type of installation.

FIG. 6 VARIOUS SETTINGS