QSC SF-3 User manual

PERFORMANCE ACCESSORIES
1675 MacArthur Boulevard
Costa Mesa, CA 92626
Ph: 800/854-4079 or 714/957-7100
Fax: [phone]
www.qscaudio.com
SF-3
Subwoofer Filter
Basic Description
The SF-3 subwoofer filter allows the addition of subwoofers to an
existing full-range system, offering adjustable low-pass filtering and
high-passsubsonicfilteringwithoptionalB6boostandmono-summing.
Theunit mounts to therear panel ofa two-channel DCA orCX amplifiers
to save cost and rack spack. The amplifier’s DataPort provides the
accessory’s operating power and receives the output signals,eliminating
added external wiring or power transformers.
For subwoofer material derived from full-range audio, a 4th-order
Linkwitz-Riley low-pass filter lets you set the upper range of the sub-
woofer band to 80,150,or 250 Hz.The subsonic filter offers a range of
roll-off frequencies from 20 to 50 Hz to protect subwoofers from over
excursion, with optional equalization to extend the response of B6
speaker enclosures. A trim control provides 0 to 20 dB of attenuation
for matching levels among the various frequency bands. Filter fre-
quencies are programmable via provided SIP resistor networks.
Compatible amplifier models
DCA 1222,DCA 1622,DCA 2422,DCA 3022,and DCA 3422
CX302,CX502,CX702,CX902,CX1102,CX302V,CX602V,andCX 1202V
SF-3 Features
•For 2-channel DCA series or CX series amps
•Designed for professional cinema applications or installed
sound systems
•Mounts directly to back of amplifier;interfaces with amplifier
via DataPort
•Adds low-pass and subsonic filtering functions without requiring
additional rack space,cabling,or AC outlets
•Precision components for accurate performance
•Active balanced XLR inputs
•Selectable subsonic frequencies from 20 Hz to 50 Hz
•Defeatable 24 dB/octave low-pass filter for deriving subwoofer
program from mono or stereo full-range audio
OFF ON
12345678910
DCA amplifier
SF-3
subwoofer filter
Ch. 1
Ch. 2
Cinema processor
subwoofer output
or full-range audio
SF-3 Spec Sheet.11/7/00

QSC Audio Inc. 1675 MacArthur Boulevard • Costa Mesa, CA 92626 •Ph: 800/854-4079 or 714/957-7100 •Fax: [phone] • www.qscaudio.com
SF-3 SPECIFICATIONS
GENERAL INFORMATION
Subsonic filter frequency
Subsonic fitler Q
Output to amplifier
Accessory’s operating power
GENERAL AUDIO
Input stage type
Male HD-15 connector to amplifier DataPort
Male HD-15 connector to amplifier DataPort
Electronically balanced differential; both inputs summed
Output stage type Balanced
Dynamic range 118 dB nominal
Total harmonic distortion Less than 0.1%
Signal to noise ratio Min. 103 dB
Subsonic filter type 2nd-order, 12 dB/octave
Low-pass filter type
Low-pass roll-off slope 4th-order Linkwitz-Riley alignment; -6 dB at crossover frequency 24 dB/octave rolloff
SF -3
Supply Voltage (no load) +15 volts provided by amplifier, -15 volts provided by internal charge-pump converter.
Supply Current Requirements Less than 50 mA
Operating Temperature 0–70oC
Input type, each channel Electronically balanced differential
Input impedance 22.6 k‰balanced; 11.3 kΩunbalanced
CONTROLS (each channel) Selectable using SIP resistor networks: 20, 25,30, 35,40 & 50 Hz
Selectable using DIP switch: 0.707 (Butterworkth) or 2 (6 dB peak)
Low-pass filter Bypass or engage using DIP switch
Low-pass filter frequency
Gain adjustment Selectable using SIP resistor networks: 80, 150 & 250 Hz
Trim potentiometer 0–20 dB attenuation
CONNECTORS
Input Two female 3-pin XLR
1
1
1
2
2
2
LF-3LF-3SF-3
1
1
1
1
2
2
2
2
XC-3XC-3XC-3
L
C
R
LS
RS
Sub
5.1
Cinema
Processor
DCA
DCA
DCA
DCA
Left
MF
Center
MF
Right
MF
Left
Surround
Left
HF
Center
HF
Right
HF
Right
Surround
DCA
DCA
DCA
Left
LF
Right
LF
Sub
Center
LF
Sub
Spare
DataPort
Audio* in
Channel 1
Audio* in
Channel 2
SF out
Channel 1
SF out
Channel 2
Level trim
0…-20 dB
SF filtering
*Either full-range (for derived subwoofer program)
or discrete subwoofer program