QSC SC-424 User manual

Developed specifically for the unique requirements
of professional motion picture playback, the SC-424
extends QSC’s commitment to the cinema market.
As a member of the DCS Digital Cinema Speaker
Series, the SC-424 is a four-way, selectable tri or
quad-amplified screen channel loudspeaker system
comprised of two main units - the MHV-1090 mid-
high-very high-frequency system and the LF-4215
low-frequency system.
The MHV-1090 mid-high-very high system features
a high output, horn loaded 10" midrange cone
driver and a coaxial neodymium high-frequency/very
high-frequency compression driver . The MHV-1090
includes a driver protection network and a passive
crossover for tri-amp operation. The protection circuitry
prevents low-frequency signals from damaging the
high-frequency and very high-frequency driver. A
high power 10" cone driver allows operation as low
as 250 Hz and the advanced phase plug coupling
permits a crossover point of up to 1800 Hz to the
high-frequency horn. This ensures that most of the
dialog range is reproduced by a single element, for
unmatched intelligibility.
The coaxial neodymium high-frequency/very high-
frequency compression driver provides a dramatic
improvement in dynamic response, clarity and
transparency. The annular high-frequency diaphragm
covers the frequency range between 1800 and
7000 Hz with a smooth, linear response. The large
diaphragm excursion of +/-0.8 mm results in high
output and increased power handling. The very high-
frequency driver covers the frequency range from
7000 to 22,000 Hz and eliminates the dome break
up of conventional drivers that can cause resonance
and harsh, metallic sound.
The LF-4215 dual 15” (381mm) low-frequency
enclosure is designed specifically to address the
extended low-frequency response required for cinema
applications. The LF-4215 covers the frequency range
from 35 Hz to 250 Hz. Close coupled woofers (CCW),
with their tight spacing between woofers, improves
coupling and keeps coverage angles wide over a greater
frequency range than more widely spaced designs.
The SC-424 is designed for ease of installation. The
MHV-1090 components come pre-assembled to
reduce field assembly time. Three bolts are all that are
required to secure the MHV-1090 to the top of the
LF-4215 enclosure.
SC-424
Cinema Loudspeaker System
Features
• Four-way selectable, tri or quad- amplified screen channel system
• Unique HF/VHF diaphragm has less mass than traditional diaphragms resulting in
exceptional dynamic range, extended high frequency response and lower distortion
• LF-4215 is constructed of MDF and is heavily braced
• Low-distortion waveguides provide highly articulate dialogue
• Shallow depth (20”) facilitates installation
• THX™ approved for professional cinema applications
NEW!
Specifications SC-424
Nominal Coverage 90° horizontal x +20 to -30° vertical
Frequency Range (-6 dB) 33 - 20 kHz
Active Crossover Frequencies 250, 1700 and 6000 Hz, 24 dB per octave
LF-4215 MHV-1090
Impedance 4ΩMF: 8ΩHF: 8ΩVHF: 8Ω
Sensitivity 1 watt /1 meter,
half space
99.5 dB Tri-amp
MF:105 dB
HF/VHF: 110 dB
Quad-amp
MF: 105 dB
HF: 110 dB
VHF: 110 dB
Maximum Input Power1
8 hours of 6 db crest factor
IEC 268 noise spectrum
800 W RMS MF: 275 W RMS
HF/VHF: 230 W RMS
MF: 275 W RMS
HF: 150 W RMS
VHF: 80 W RMS
2 hours of 6 db crest factor
pink noise, 50 Hz - 20 kHz,
AES method
1000 W RMS MF: 800 W RMS
HF/VHF: 500 W RMS maximum
Recommended
Amplifier Power
1600 W RMS maximum MF: 800 W RMS
HF: 500 W RMS
VHF: 300 W RMS maximum
Recommended Processing Subsonic filter below 30 Hz,
>18 dB per octave
4th order LR crossover at 250, 1700 and
6000 Hz via QSC DCM or QSControl.net
Connectors Barrier strip screw terminals accept up to #10 AWG stranded wire
Transducers Two 15" (381mm) high
efficiency, extended bass
woofer featuring a 4" copper
voice coils
MF: 10" high-effeciency, horn-loaded
cone with pahse plug
HF/VHF: coaxial neodymium compression
driver with 3.5" (90 mm) HF diaphram
and 1.75" (44 mm) VHF diaphram
Enclosure Quasi B4 alignment, ported
enclosure with fully flared
ports, symmetrical port design,
tuned to 36 Hz, constructed
of MDF and heavily braced.
Features vandal resistant
woofer mounting bolts
Tilt/Pan Bracket
±10° vertical tilt
±10° horizontal pan
Dimensions (HWD) 36" x 30" x 20.3"
(910 mm x 762 mm x 516 mm)
39" x 30" x 20"
(990 mm x 762 mm x 508 mm)
Weight - Net 172 lbs (78 kg) 84 lbs (38.5 kg)
System Weight 256 lbs (116 kg)
Baffle Cut-Out 76" 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.
THX is a trademark of THX Ltd.

SC-424 Dimensions
qscaudio.com
Specifications subject to change without notice.
1675 MacArthur Boulevard • Costa Mesa, CA 92626 • Ph: 800/854-4079 or 714/957-7100 • Fax: [phone]
SC-424 Spec Sheet - 04/23/07
Top
Side
21.7"
551 mm
20.3"
515 mm
30"
762 mm
Front
75"
1900 mm
18.9"
480 mm
39"
990 mm
36"
910 mm
4"
102 mm