Soundstream Technologies Class A 5.0 Mode D'Emploi

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LSE.Q THEORY AND USE (Class A 10.0) 
LSE.Q is a unique subwoofer control circuit 
i n c l u d e d   w i t h   t h e   S O U N D S T R E A M 
REFERENCE Class A 10.0  amplifier.  It is 
capable of removing subsonic energy in program 
material.  The circuit consists of two controls.  
One adjusts the frequency of operation and the 
other adjusts the range of boost.  With both 
controls adjusted fully counter-clockwise, no 
boost is applied and the amplifier is flat in 
response down to 30 Hz.  
The frequency control (Hz) adjusts the starting point of the subsonic 
filter.  This  high pass filter can be 
adjusted from 30 Hz up to a 
maximum of 60 Hz.  This control 
is useful for setting the lowest 
frequency that your subwoofer will 
see.  (See figure 1) 
The Q control adjusts the 
amount of boost applied at the set 
frequency.  This is adjustable 
from .707 (flat) to 2.8 (+9 dB).  
(See figure 2) 
 When the Q is set to .707 
(Butterworth), LSE.Q acts as a 
sub-sonic filter only.  (See figure 
3)  
The simple act of removing the 
signal below the vented tuning 
frequency can improve system 
output by as much as 3 dB.   With Q values greater than .707, boost is 
added to the sub-sonic filter. (see 
figure 4) 
 Application 
Woofers in vented enclosures have 
good power handling characteristics 
above the tuning frequency, but 
below the tuning frequency, power 
handling drops off considerably.  
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Frequency (Hz)
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-30
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-20
-5
dB
0
5
10
50
100
200
FIG. 3  Variable High Pass 
dB
Frequency (Hz)
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-30
10
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-15
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5
0
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10
50
100
200
FIG. 2  Variable “Q” 
 Q=2.8 
Q=0.707 
dB
Frequency (Hz)
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-30
10
-25
-15
-10
5
0
-5
10
50
100
200
FIG. 4  Variable “Q” 
FIG. 1  LSE.Q 
most amplifiers in the Class A 5.0, and over twelve times in the Class A 
10.0!  More drive current maintains the amplifiers' performance into low 
impedance loads. 
Drive Delay
TM
 Muted Turn-on/off Circuit - A unique circuit which 
completely eliminates any amplifier-related turn-on/off noises. 
Flexible Dual Input Level Sensitivity accepts 2 voltage ranges; from 200 
mV to 2.0 V and from 500 mV to 5.0 V, permitting maximum output from the 
amplifier with virtually any source unit. 
Differential Balanced Input Design for added immunity to noise caused by 
component and vehicle electrical system interaction when using Unbalanced 
RCA inputs. 
True Balanced Input for professional-quality performance and noise 
cancellation.  The 6-pin din plug carries (+) and (-) Signal information for Left 
and Right channels, audio ground, and ±15 Vdc to operate the Soundstream 
BLT Balanced Line Transmitter. 
AIRBASS™ ACCESSORY OPTION 
 
Soundstream's new AIRBASS™ feature can be added to the REFERENCE 
Class A amplifiers.  This feature allows wireless RF remote control level 
adjustment of the amplifier. 
NOTE:  The AIRBASS™ accessory is intended to be used only while the 
REFERENCE Class A amplifiers are driving subwoofers.  When the  
AIR
BASS™ accessory is added to a REFERENCE Class A amplifier, it 
automatically configures the amplifier into Bridged Mono mode.  (The Coherent 
Stereo / Mixed Mono / Bridged Mono switch is bypassed.)  Therefore, when 
using AIR
BASS™, follow the Bridged Mono input and output wiring 
Installing AIRBASS™ involves removing the bottom plate of the amplifier, 
adding the AIRBASS™ circuit board, and flipping a switch.  The switch is 
labeled on the amplifier's main circuit board.  DO NOT set the AIRBASS™ 
switch to the "IN" position unless the AIRBASS™ module has been added.  
DO NOT move the AIRBASS™ switch while the amplifier is "ON".  Doing so 
may damage your speakers.  (Please refer to the AIRBASS™ owner's / 
installation manual for more details.)