Soundstream Technologies 355, 555, 255 Installation Step, Selecting the Speaker Output Mode

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

.

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:

Application
Subwoofer drivers in general have excel- lo
lent power handling characteristics over	5
their operational bandwidth. This bandwidth	.t
is determined by many factors, including dB-l~					I		I
driver design and enclosure type. It is pos-	15		!
sible to overdrive any subwoofer driver by	-*Or		f				t
			!				I
sending powerful signals outside of its op-	-*’		I			.	1
			!				1
erational bandwidth. These potentially dam-	-3010	:recuency (HZI	5 0	100			260

aging signals can be removed by adding a FIG. 2 VARIABLE BOOST

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

clock-wise (0) position. -5

dB

-10

2. Set the bass control switch to ,5

“HAWKINS BASS CONTROL”. 20.

3.Play moderate to loud bass material.

-301 0	Frequancy ( H z )	5 0	1 0 0	2 3 0
4. Adjust the boost (Q) control until you	FIG. 3 Limited Excursion
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.

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		,;	1	-	-rTl	\.
, hi	/’		.__			1
			‘\		5CH
.					/’
BRlDGi5-MoNO				..__	__,’
			STEREO
- L+	- R +	-	L +		-R+
__~ ____._- __.____ \		/---------		---	- - - --__ ‘~

15