QSC SF3

The SF-3 subwoofer filter allows the addition of subwoofers to an existing full-range system, offering adjustable low-pass filtering and high-pass subsonic filtering with optional B6 boost and mono-summing. The unit mounts to the rear panel of a two-channel DCA or CX 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 subwoofer 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 frequencies are programmable via provided SIP resistor networks.

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 programfrom mono or stereo full-range audio

Specifications:

• Supply Voltage (no load) +15V amplifier, -15V internal charge-pump converter
• Supply Current Requirements: Less than 50 mA
• Operating Temperature: 0-70 degrees Celsius
• Input Type (each channel): Electronically balanced differential
• Input Impedance: 22.6 kohm balanced, 11.3 kohm unbalanced
• Subsonic Filter Frequency: Selectable using SIP resistor netowrks: 20, 25, 30, 35, 40 & 50 Hz
• Subsonic Filter Q: 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: Selectable using SIP resistor networks: 80, 150 & 250 Hz
• Gain Adjustment: Trim potentiometer 0-20 dB attenuation
• Input Connectors: Two female 3-pin XLR
• Output to Amplifier Connector: Male HD-15 connector to amplifier DataPort
• Accessory's Operating Power Connector: Male HD-15 connector to amplifier DataPort
• Input Stage Type: 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: 4th-order Linkwitz-Riley alignment, -6 dB at crossover frequency
• Low-pass Filter Roll-off Slope: 24 dB / octave rolloff