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2

CONFIGURATION

SETTING THE SUBSONIC FILTER FREQUENCY

The subsonic (highpass) filter on Channel 1 cannot be bypassed, and Channel 2 should only be bypassed
in the bridged mono mode. Plug-in SIP resistor network 

RN3

 sets the high-pass frequency for both channels

1 and 2. Table 2 shows the resistor value to be used for the frequency you desire. Typical subsonic
frequencies available with the provided SIP resistor networks are 20, 25, 32, 35, 40, 50, 63, and 80 Hz.
Consult your subwoofer manufacturer if you are unsure of what frequency to use.

If you desire a 6-dB boost at the low end of the subwoofer frequency range, set the slide switch SW1 to “ON”;
otherwise set it to “OFF.” Such a boost is popular with users of Electro-Voice B6 subwoofer enclosures.

SETTING THE SUBWOOFER UPPER FREQUENCY LIMIT

The low-pass filter sets the upper limit of the subwoofer frequency range. Plug-in SIP resistor network 

RN4

sets the low-pass frequency for both channels 1 and 2. Table 2 shows the resistor value to be used for the
frequency you desire. Typical frequencies available with the provided SIP resistor networks are 100, 135,
160, 200, and 250 Hz.  Consult your subwoofer manufacturer if you are unsure of what frequency to use.
Whatever frequency you choose should be higher than that of the subsonic filter.

SETTING DIP SWITCH SW2

Determine the configuration you desire and set the DIP switches as described below.

Positions 1 through 4 and 9 and 10

First, decide whether you need “Mono Sum” or “Stereo” operation. This will determine the settings of
positions 1 through 4 and 9 and 10 of DIP switch SW2.

Mono Sum

Because it is difficult for listeners to sense directionality of low audio frequencies, many subwoofer
systems are set up for monaural operation, with both channels summed together. For mono
summed operation, set the amplifier mode switch to “STEREO” and SW2 as follows:

Position 1

OFF

Position 2

ON

Position 3

ON

Position 4

OFF

Position 9

OFF

Position 10

ON

Continue to “Positions 5 through 8” and set those switches to engage both channels’ low-pass
filtering.

TABLE 2

Frequency

Resistor Network Value (RN3 or RN4)

20

82K

Factory set for RN3

25

68K

32

56K

35

47K

40

39K

50

33K

63

27K

80

20K

100

18K

135

12K

160

10K

200

8.2K

250

6.8K

Factory set for RN4

Summary of Contents for SF-1

Page 1: ...9 SF 1 Subwoofer Filter Rev A Owner s Manual FPO...

Page 2: ...10...

Page 3: ...is detailed below The use of the SF 1 for cinema subwoofer installations can reduce the chance of speaker damage by digital soundtracks Low frequency information below the box tuning frequency can de...

Page 4: ...desire Typical frequencies available with the provided SIP resistor networks are 100 135 160 200 and 250 Hz Consult your subwoofer manufacturer if you are unsure of what frequency to use Whatever fre...

Page 5: ...bwoofer engage the filtering Typical cinema subwoofers are an exception the low pass filter should be bypassed in this application as cinema processors typically perform this function Position 5 ON if...

Page 6: ...to the ribbon connector on the input panel card The ribbon cable attaches to J4 on the SF 1 figure 2b The connectors are keyed make sure they line up properly and the ribbon cable is not twisted befo...

Page 7: ...rth Q 0 707 LPF and unboosted subsonic filter second order 6 dB boost Q 2 boosted subsonic filter DIP SWITCH FUNCTIONS TABLE 3 DIP SWITCH SW2 Mode 1 2 3 4 5 6 7 8 9 10 Mono Sum OFF ON ON OFF Stereo ON...

Page 8: ...Surround channels may benefit from the use of a high pass filter at 80 Hz also installed in position RN3 For cinema subwoofers that require an EQ boost use the following switch settings SW1 slide swit...

Page 9: ...e components in your unit are QSC specific parts that require QSC replacements Comprehen sive service manuals for some models are available at QSC TECHNICAL ASSISTANCE If you suspect that your amplifi...

Page 10: ...many countries The service centers in your country may be located by your dealer distributor or by contacting QSC Technical Services APPENDIX C IMPORTANT ADDRESS AND TELEPHONE INFORMATION Factory addr...

Page 11: ...11...

Page 12: ...ODUCTS INC 1675 MacArthur Blvd Costa Mesa CA 92626 USA Ph 714 754 6175 Fax 714 754 6174 Email INFO qscaudio com Web http www qscaudio com QSC and the QSC logo are registered with the U S Patent and Tr...

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