QSC SC-324 Owner's Manual

1675 MacArthur Blvd., Costa Mesa, CA, 92626 USA
Main Number [phone] Sales & Marketing [phone] or toll free (USA only) [phone]
Customer Service(714) 957-7150 or toll free (USA only) [phone]

Cinema Mid-High-Very High Loudspeaker System User Manual

MHV-1090 10” (254mm) mid, coax high- very high compression driver

Introduction

The MHV-1090 system provides the mid, high, and very high frequency components of
four-way screen channel loudspeaker system for high performance cinema applica­tions. It was designed to operate with and be directly mounted on QSC’s cinema low
frequency enclosures.

The high frequency horn is a low-distortion waveguide providing highly articulate dia­logue without the coloration associated with conventional horn loudspeakers. Both
horns feature broad horizontal and vertical coverage to ensure audio integrity is deliv­ered to every seat in the auditorium. The driver assemblies are mounted on an adjust­able pan and tilt bracket that has an integral aiming sight, simplifying installation.

The MHV-1090 includes a driver protection and high-very high frequency crossover
network to assure reliable operation. DC blocking capacitors protect against DC or
low-frequency signals that could damage an unprotected driver. A 12 dB per octave
crossover seamlessly blends the high and very high frequency elements when oper­ated in tri-amp mode. Outboard processing is required to form the crossover between
the low, mid, and high-very high frequency drivers.

30”

(762mm)

Tri-amp or quad-amp operation is possible using a selector switch mounted on the
INPUTS connection panel. The tri-amp setting provides a built-in passive crossover
network between high and very high frequency drivers. Separate amplifiers and active
crossovers are required for the low, mid, high-very high frequency channels. Quad­amp setting disables the internal high-very high frequency crossover and each driver
is driven independently by its own amplifier and active crossover; one each required
for the low, mid, high, and very high frequency drivers.

The MHV-1090 components come pre-assembled to reduce field assembly time. Three
bolts are all that are required to secure the assembly to the top of a QSC low fre­quency enclosure.

Install in accordance with QSC Audio Product’s instructions and a
licensed, professional engineer. Only use attachments, mounts,
accessories, or brackets specified by QSC Audio Products, Inc. Refer
all servicing to qualified personnel. Servicing is required when the
apparatus has been damaged in any way.

WARNING! Before placing, installing, rigging, or suspending any
speaker product, inspect all hardware, suspension, enclosures,
transducers, brackets and associated equipment for damage. Any
missing, corroded, deformed or non-load rated component could sig­nificantly reduce the strength of the installation, placement, or array.
Any such condition severely reduces the safety of the installation and
should be immediately corrected. Use only hardware which is rated
for the loading conditions of the installation and any possible short­term unexpected overloading. Never exceed the rating of the hard­ware or equipment. Consult a licensed, professional engineer when
any doubt or questions arise regarding a physical equipment installa­tion.

39”

(991mm)

“QSC” and the QSC logo are registered with the U.S. Pat ent and Trademark Off ice

QSC® is a registered trademark of QSC Audio Products, Inc.

© Copyright 2007, QSC Audio Products, Inc.

TD-000246-00-A

20”

(508mm)

*TD-000246-00*

Mounting

Attaching to Low Frequency Enclosure

The MHV-1090 attaches to the top of QSC low frequency enclosures with three 0.75” long 5/16”-18 TPI bolts. ensure the use of lock washers on all bolts.
The bolts and washers ship installed on the low frequency enclosure. We recommend the use of serviceable thread locking compound when installing the
bolts to prevent loosening due to vibration. Do not fully tighten the mounting hardware before aiming in the horizontal plane (see below).

Aiming

Aim the horn in the horizontal plane (pan) before tightening the three bolts securing the MHV-1090 to the low frequency enclosure. Adjust the vertical tilt
with the vertical adjustment bracket. The mid-high assembly is equipped with an aiming sight to assist in achieving desired coverage quickly and easily.
For typical applications, the aim point should be the center seat in the back row of the auditorium. If the cinema screen has already been installed, a flash­light placed at the desired aiming point can be seen through the screen perforations in a darkened auditorium.

Where the sight holes are located:

How to use the sights:

Settings and Connections

TRI-AMP / QUAD-AMP Operating Mode Selection

Set the operating mode selector switch to TRI-AMP or QUAD-AMP, depending on your screen chan-
nel signal processing and amplification set-up. The mid frequency driver will require connection to its
rear cover terminals, regardless of mode selection. The low frequency driver will also require its own,
separate connections. The only connection difference between tri-amp and quad-amp modes is in
quad-amp mode, the very high frequency signal will require connection to the terminals labeled VHF.

Aim point:

Mode selector switch set to
TRI-AMP and the required
HF/VHF connection:

TRI-AMP-When set to TRI-AMP, the MHV-1090 input panel connections accept high frequency/very

high frequency signals on one set of inputs and uses an internal crossover network between the high
and very high frequency drivers.

QUAD-AMP- When set to QUAD-AMP, the MHV-1090 input panel accepts separate high and very
high frequency signals on two separate sets of inputs. The internal crossover network is bypassed and
only the protective circuitry for the high frequency and very high frequency driver remains. Each of the
driver’s signals must have the appropriate upstream signal processing.

•Do not connect amplifiers directly to the high/very high frequency coaxial driver
inputs!

• Always use the crossover INPUTS terminal strip for high and very high frequency
input(s)

•The mid frequency driver and the low frequency enclosure are connected directly
to their own separate amplifiers regardless of mode selector switch setting.

2

HF/VHF

Mode selector switch set to
QUAD-AMP and the required sep­arate HF and VHF connections:

VHF

HF

INPUTS Terminals

The MHV-1090 has barrier strip screw terminals that accept up to #10 AWG (5.3mm

2

) stranded loudspeaker wire. Observe proper polarity. Use the

largest wire size and shortest wire length for the application.

OUTPUTS Terminals

The OUTPUT terminals are factory-connected to the high and very high frequency drivers. These terminals should ONLY be connected to their respec-
tive driver. Do not connect signals to these terminals as all protection and equalization circuitry will be bypassed. They are not for daisy chaining the
signals to other drivers.

NOTE! Maintain proper loudspeaker connection polarity throughout the entire system for maximum performance. Do not apply
full range signal to the MHV-1090! There is a high/very high frequency passive crossover for tri-amp mode only. There is no
crossover connected when operating in quad-amp mode. All required signal processing must be done before the signal is
applied to the loudspeaker. Do not connect any signal to the upper sets of OUTPUT terminals.

TRI-AMP mode connections- Ensure the mode selector switch is set to TRI-AMP, connect the low frequency signal to the low frequency enclosure;

connect the mid frequency signal to the mid frequency driver; connect the high/very high frequency signal to the VHF/HF terminals on the INPUTS ter­minal strip.

Signal Processing

MHV-1090

HF/VHF

Amplification

MF

Amplification

HF/VHF

MF

LF

Low Frequency Enclosure

LF

3

QUAD-AMP mode connections- Ensure the mode selector switch is set to QUAD-AMP, connect the low frequency signal to the low

frequency enclosure; connect the mid frequency signal to the mid frequency driver; connect the high frequency signal to the HF termi­nals on the INPUTS terminal strip; connect the very high frequency signal to the VHF terminals on the INPUTS terminal strip.

Signal Processing

MHV-1090

VHF

HF

MF

Amplification

Amplification

VHF

HF

MF

LF

LF

Low Frequency Enclosure

4

MHV-1090 Specifications (subject to change without notice)

Freq. Range 180 - 20k Hz (-6dB, full space)

Nominal Coverage 90° horizontal X +20 to -30° vertical (50° total, adjustable mount provides for vertical plane adjustments. The horizontal

plane can be adjusted by altering mounting position on the low frequency enclosure before tightening bolts.

DI: 9 dB (400 to 16k Hz average)

Q: 8 (400 to 16k Hz average)

Max. Output:, calculated Mid frequency 135.5 dB SPL
(1 meter, full space) Tri-amp mode: high frequency/very high frequency 138 dB SPL

Quad-amp mode: high frequency 138 dB SPL, very high frequency 135 dB SPL

Impedance: Tri-amp mode: 8 ohms nominal, mid frequency and high/very high frequency

Quad-amp mode:8 ohms nominal, mid, high, and very high frequency

Maximum Input Power Mid frequency: 275 W
(AES method, 2 hours) Tri-amp mode: high/very high frequency 155 W (calculated, sum of high and very high frequency individual ratings)

Quad-amp mode:high frequency 85 W, very high frequency 70 W

Sensitivity Mid frequency: 105 dB SPL
(1 Watt, 1 meter) Tri-amp mode: high/very high frequency 110 dB SPL

Quad-amp mode:high frequency 110 dB SPL

very high frequency 110 dB SPL

Crossover Frequencies Tri-amp mode: mid frequency 250 Hz or higher, high/very frequency 1.7 kHz, both 24 dB/octave

Quad-amp mode: mid frequency 250 Hz or higher, high frequency 1.7 kHz, very high frequency 6.0 kHz, all 24 dB/octave

Crossover Network High frequency to very high frequency crossover at 7 kHz, 12 dB per octave, only in tri-amp mode. Quad-amp mode

switch setting removes crossover circuit from signal path, but leaves DC blocking capacitors in circuit.

Connectors Mid frequency driver: barrier strip screw terminals on mid frequency driver accept up to #10 AWG stranded wire.

High frequency, very high frequency drivers: barrier strip screw terminals accept up to #10 AWG stranded wire

Tri-amp mode connect high frequency/very high frequency program only to VHF/HF INPUTS terminals
Quad-amp mode connect high frequency program to HF INPUTS terminals and connect very high frequency

program to VHF INPUTS terminals.

Transducers Mid frequency: 10" high efficiency mid-range, phase-ring loaded

High frequency: 1.5" exit, 3.5" voice coil polyester diaphragm coaxial compression driver
Very High frequency: 1.5" exit, 1.75" voice coil polyester diaphragm coaxial compression driver

Mounting Hardware: Attaches to top of QSC’s low frequency cinema enclosures using three 5/16”-18 x 3/4” long bolts (supplied on low fre-

quency enclosure)

Size 39” high x 30” wide x 20” deep (991 x 762 x 508mm)

Weight 73.5 lb. (33 kg) net

5

MHV-1090 SPL vs. Frequency, Tri-amp, No Screen

SPL (dB, normalized)

mid

high/very high

Frequency (Hz)

MHV-1090 SPL vs. Frequency, Quad-amp, No Screen

mid

high

very high

SPL (dB, normalized)

Frequency (Hz)

6

MHV-1090 SPL vs. Frequency, X-curve, Tri-amp, With and Without Screen

X-curve +3 dB

without screen

SPL (dB, normalized)

Frequency (Hz)

X-curve -3 dB

with screen

SPL (dB, normalized)

MHV-1090 SPL vs. Frequency, X-curve, Quad-amp, With and Without Screen

X-curve +3 dB

X-curve -3 dB

Frequency (Hz)

without screen

with screen

7

Warranty (USA only; other countries, see your dealer or distributor)

Disclaimer

QSC Audio Products, Inc. is not liable for any damage to amplifiers, or any other equipment that is caused by negligence or
improper installation and/or use of this loudspeaker product.

QSC Audio Products 3 Year Limited Warranty

QSC Audio Products, Inc. (“QSC”) guarantees its products to be free from defective material and / or workmanship for a period
of three (3) years from date of sale, and will replace defective parts and repair malfunctioning products under this warranty
when the defect occurs under normal installation and use - provided the unit is returned to our factory or one of our authorized
service stations via pre-paid transportation with a copy of proof of purchase (i.e., sales receipt). This warranty provides that
the examination of the return product must indicate, in our judgment, a manufacturing defect. This warranty does not extend
to any product which has been subjected to misuse, neglect, accident, improper installation, or where the date code has been
removed or defaced. QSC shall not be liable for incidental and/or consequential damages. This warranty gives you specific
legal rights. This limited warranty is freely transferable during the term of the warranty period.

Customer may have additional rights, which vary from state to state.

In the event that this product was manufactured for export and sale outside of the United States or its territories, then this lim­ited warranty shall not apply. Removal of the serial number on this product, or purchase of this product from an unauthorized
dealer, will void this limited warranty. Periodically, this warranty is updated. To obtain the most recent version of QSC’s war­ranty statement, please visit www.qscaudio.com. Contact us at 800-854-4079 or visit our website at www.qscaudio.com.

Contacting QSC Audio Products

Mailing address:QSC Audio Products, Inc.
1675 MacArthur Boulevard
Costa Mesa, CA 92626-1468 USA

Telephone Numbers:
Main Number [phone]
Sales & Marketing [phone] or toll free (USA only) [phone]
Customer Service(714) 957-7150 or toll free (USA only) [phone]

Facsimile Numbers:
Sales & Marketing Fax[phone]
Customer Service Fax[phone]

World Wide Web:www.qscaudio.com
E-mail:[e-mail]
[e-mail]

QSC Audio Products, Inc. 1675 MacArthur Boulevard Costa Mesa, California 92626 USA

©2007 “QSC” and the QSC logo are registered with the U.S. Patent and Trademark Office.

1675 MacArthur Blvd., Costa Mesa, CA, 92626 USA
Main Number [phone] Sales & Marketing [phone] or toll free (USA only) [phone]
Customer Service [phone] or toll free (USA only) [phone]

Cinema Loudspeaker Systems User Manual

LF-3215 Low Frequency Loudspeaker

Introduction

The LF-3215 dual 15” (381mm) low frequency enclosure is designed specifically for cinema
applications. Meeting cinema requirements for extended low frequency response differenti­ates the LF-3215 from more conventional “rock-and-roll” woofer systems. The LF-3215 cov­ers the frequency range from 32 Hertz to 1500 Hertz, depending upon the high frequency
system requirements. With its tight spacing between woofers, the LF-3215 offers improved
coupling and keeps coverage angles wide over a greater frequency range than more widely
spaced designs.

The 300 watt, 15” transducers are well suited for cinema use. They feature 3” (76mm) voice
coils, 120 oz.(3.4kg) ceramic magnets, and vented pole pieces to ensure cool operation.
Cooler temperatures increase transducer lifespan and decrease the problem of power com­pression at high power levels. The suspension and voice coil of each transducer have been
designed to provide low distortion and high impact bass at high power levels.

The enclosure is constructed of high quality medium density fiberboard panels with stiffen­ing braces on all panels and features separate woofer chambers. This prevents over-excur­sion of a transducer caused by improper box loading in the rare event of a transducer failure.
The eight stiffening braces reduce panel resonance.

Mounting points for mid-

high or high frequency

system

Both internal and external port openings are fully radiused ensuring smooth air flow at high
power. This prevents audible port turbulence noise.

With symmetrical port loading, bass ports are evenly spaced on each side of the transduc­ers, making internal pressure more uniform across the back surface of the transducer. This
prevents the cone from being displaced to one side or another by unbalanced forces, reduc­ing the chance of driving the voice coil out of the center of the gap at high power levels.

Three T-nuts in the top of the enclosure provide easy mounting of QSC’s HF-63 high fre­quency system, or MH-1063 mid-high frequency system.

Enclosure is not designed to be suspended, flown, or rigged. Do not sus­pend, fly, or rig this enclosure.

This product is capable of producing sound pressure levels that can perma­nently damage human hearing. Always keep sound pressure levels in the
listening area below levels that can damage human hearing.

Install in accordance with QSC Audio Product’s instructions and a
licensed, professional engineer. Only use attachments, mounts, accesso­ries, or brackets specified by QSC Audio Products, Inc. Refer all servicing
to qualified personnel. Servicing is required when the apparatus has been
damaged in any way.

WARNING! Before placing, installing, rigging, or suspending any speaker
product, inspect all hardware, suspension, cabinets, transducers, brackets
and associated equipment for damage. Any missing, corroded, deformed or
non-load rated component could significantly reduce the strength of the
installation, placement, or array. Any such condition severely reduces the
safety of the installation and should be immediately corrected. Use only
hardware which is rated for the loading conditions of the installation and
any possible short-term unexpected overloading. Never exceed the rating
of the hardware or equipment. Consult a licensed, professional engineer
when any doubt or questions arise regarding a physical equipment installa­tion.

*TD-000173-00*

“QSC” and the QSC logo are registered with the U.S. Pa tent and Trademark Office

QSC® is a registered trademark of QSC Audio Products, Inc.

© Copyright 2004, QSC Audio Products, Inc.

TD-000173-00 rev.C