Soundstream Technologies Class A 5.2 102 dimensions Hawkins Bass Control Theorv and Use

Hawkins Bass Control - Theorv and Use

HAWKINS

FREQ BOOST

Q

HAWKINS30-70 Hz SUBSONIC 13-30 Hz

Hawkins Bass Control (parametric) is a unique subwoofer control circuit included with the Soundstream RUBICON Class A 10.2 and 5.2 am- plifiers. It is capable of removing subsonic energy in program material while boosting subwoofer fre- quencies. The circuit consists of two controls. One adjusts the frequency of operation and the other adjusts the range of boost. With both controls ad- justed fully counter-clockwise, no boost is applied and the amplifier is flat in response down to 20 Hz.

Application				I
Subwoofer drivers in qeneral have ex-		I I	IIII
cellent power handling characteristics
over their operational bandwidth. This -5
bandwidth is determined by many fat- dB-lob
tors, including driver design, and en-
closure type. It is possible to overdrive
any subwoofer driver by sending pow-	Frequency(Hz) 50		100
erful signals outside of its operational
	FIG. 5 LIMITED EXCURSION

bandwidth. These potentially damag-

FIG. 1 BASS CONTROL

ing signals can be removed by adding a subsonic filter. Figure 5 shows the effectiveness of the Hawkins Bass Control on woofer excursion in a vented

The frequency control (Hz) adjusts	, o
the starting point of the subsonic fil-	5
ter. On the RUBICON Class A 10.2	0

and 5.2, the high pass filter has two dB + frequency ranges. When the bass 1:: control switch is set to “SUB SONIC”, _20 the high pass filter frequency can be - adjusted from 13 Hz up to a maxi- ‘3010I 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 dB control switch is set to “HAWKINS BASS CONTROL”, the high pass fil- ter 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 +9 dB.

241

I	I I	I	illll	2
Frequency {Hz)		50	100

FIG. 2 VARIABLE “Q”

Frequency (Hz) 50 100

FIG. 3 VARIABLE HIGH PASS

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

An easy method of optimizing your existing subwoofer enclosure with Hawkin’s “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- o
tion of boost and cut to suit your de-,, -5 I	/ I / /I/I I I I I II	I

dB

-20I

-25'

L

-3010 Frequency (Hz) 50 100

FIG. 4 VARIABLE BOOST

The Boost control adjusts the amount of level applied at the set frequency. This is adjustable from flat (OdB) to +9 dB. (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 po-

200 tentially harmful low frequencies can improve system output by as much as 3 dB. (see figure 4)

signs. So, Hawkins Bass Control can -lo
provide the “tailoring” needed for any1::
type of “assisted” design and any woofer -25
in any type of installation.	-30	Lc_.__.__- I___~L___1IL1_1Il_____________I
		10	Frequency (Hz)	50	100	200

FIG. 6 VARIOUS SElTlNGS

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