QSC LF-3115 User Manual
Developed specifically for the unique requirements
of professional motion picture playback, the SC-312X
extends QSC’s commitment to the cinema market. As
a member of the DCS Digital Cinema Speaker Series,
the SC-312X is a passive, two-way, screen channel
loudspeaker system comprised of two main units—the
HF-63X1 high frequency system and the LF-3115 low-
frequency system.
The HF-63X1 high-frequency system features a 2.5"
(63mm) titanium diaphragm compression driver
mounted on a custom designed high frequency
cinema horn with an adjustable pan and tilt bracket.
The HF-63X1 includes a driver protection and
equalization network. DC blocking capacitors protect
against DC or low-frequency signals that would
likely destroy an unprotected driver. Power limiter
circuitry protects the driver from overpowering and
a response correction filter smoothes the frequency
response of the horn/driver combination. The driver
and equalization network provides for more reliable
operation, ensuring the show will go on.
The LF-3115 15" (381mm) low-frequency enclosure
is designed specifically to address the extended low-
frequency response required for cinema applications.
The LF-3115 covers the frequency range from
35 Hz to 1000 Hz, depending upon the high-
frequency system requirements.
The SC-312X is designed for ease of installation.
The HF-63X1 components come pre-assembled to
reduce field assembly time. Three bolts are all that
are required to secure the HF-63X1 to the top of the
LF-3115 enclosure.
SC-312X
Cinema Loudspeaker System
Specifications
SC-312X
Nominal Coverage
90° horizontal x +15 to -35° vertical
Frequency Range
33 Hz - 16 kHz (-6 dB)
Impedance
8Ω
Sensitivity 1 watt /1 meter,
95 dB
half space
Maximum Input Power
1
2 hours of 6 db crest factor
150 W RMS
pinknoise, 50 Hz - 20 kHz,
AES method
Recommended Amplifier Power 300 W RMS maximum
Recommended Processing
Subsonic filter below 30 Hz, > 18 dB per octave
LF-3115
HF-63X1
Connectors
Barrier strip screw terminals
Barrier strip screw terminals
accept up to #10 AWG
accept up to #10 AWG
stranded wire
stranded wire
Transducers
One 15" (381mm) high efficiency,
1.5" (38mm) exit, 2.5" titanium
extended bass woofer featuring a
diaphragm compression driver
3" copper voice coil
Enclosure
Quasi B4 alignment, ported
Tilt/Pan Bracket
enclosure with fully flared ports,
±10° vertical tilt
symmetrical port design, tuned to
±10° horizontal pan
36 Hz, constructed of MDF and
heavily braced. Features vandal
resistant woofer mounting bolts
Dimensions (HWD)
18.5" x 30" x 20.3"
16" x 30" x 20"
(470 mm x 762 mm x 516 mm)
(406 mm x 762 mm x 508 mm)
Weight - Net
83 lbs (38 kg)
40 lbs (18.4 kg)
System Weight
123 lbs (56.4 kg)
Baffle Cut-Out
35.5" x 32"
1) Maximum input power tested in accordance with IEC 268-5 recommendations, 50 Hz - 20 kHz band limiting, 6 dB signal crest factor.
Features
• Passive, two-way, screen channel system
• SC-312X provides 90° horizontal by +15° to -35° vertical coverage
• Low distortion waveguide provides highly articulate dialogue
• Shallow depth (20") facilitates installation