QSC LF-4115 Owners manual

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-4115 Low Frequency Loudspeaker

Introduction

The LF-4115 15” (381mm) low frequency enclosure is designed specifically for cinema appli­cations. Meeting cinema requirements for extended low frequency response differentiates
the LF-4115 from more conventional “rock-and-roll” woofer systems. The LF-4115 covers the
frequency range from 33 Hertz to 1200 Hertz, depending upon the high frequency system
requirements.

The custom 400 watt, 15” transducer was developed specifically for cinema use. It features
a 4” (100mm) voice coil, 120 oz.(3.4kg) ceramic magnet, and a multi-vented pole piece to
ensure cool operation. Cooler temperatures increase transducer lifespan and decrease the
problem of power compression at high power levels. An undercut pole piece ensures the
voice coil operates in a symmetrical magnetic gap, reducing second order harmonic distor­tion. The suspension and voice coil of the transducer have been designed to provide low dis­tortion and high impact bass at high power.

The enclosure is constructed of high quality medium density fiberboard panels with stiffen­ing braces on all six panels. Both internal and external port openings are fully radiused
ensuring smooth air flow at higher power levels, preventing audible port turbulence.

Bass ports are symmetrically spaced on each side of the transducer, 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.

Three T-nuts in the top of the enclosure provide easy mounting of QSC’s HF-75 high fre­quency system, or MH-1063 mid-high 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.

Mounting points for high or
mid-high frequency system

*TD-000171-00*

“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-000171-00 rev.C

Connections

Normal Connection

The LF-4115 has barrier strip screw termi­nals for connection. The terminals accept
up to #10 AWG (5.3mm
speaker wiring. Use the largest wire size
and shortest wire length possible for a
given installation. Observe the polarity
markings and keep polarity consistent
throughout the system for best perfor­mance.

2

) stranded loud-

Normal Connection Example:

Amplifier capable of
driving 4 ohm loads

Parallel Connection of Second LF-4115

The terminals marked OUTPUT may be
used to connect another LF-4115 in paral­lel. Connect the wires as shown in the illus­tration, at right.

Parallel Connection Example:

Amplifier capable of
driving 2 ohm loads

LF-4115 Specifications (subject to change without notice)

Frequency Range: 33 - 1200 Hertz (-6dB)

29 - 3000 Hertz useable range (-10dB)

Nominal Coverage: 100° horizontal X 100° vertical at 1000 Hertz

Maximum Output:

Impedance: 4 ohms nominal

Maximum Input Power: 400 watts rms (8 hours of 6dB crest factor pink noise, 40 - 400 Hertz)

Sensitivity: 93.5dB half space, 92.0dB full space, 35 - 1000 Hertz, 1 watt, 1 meter

Recommended Processing: Subsonic filter below 30 Hertz, >18 dB per octave, maximum recommended crossover frequency is 1000 Hertz. QSC

Connectors: Barrier strip screw terminals accept up to #10 AWG (5.3mm

Transducers: 15” (381mm) high efficiency low frequency transducer featuring vented 4” (100mm) copper voice coil on Kapton®

127.0dB SPL calculated peak, 1 meter, half space, at rated rms power with 6 dB crest factor pink noise input, 35 - 1000 Hertz.

121.0dBA SPL calculated maximum continuous, 1 meter. The dBA scale is typically used to identify sound sources
which can cause permanent hearing loss.

4.3 ohms minimum, 160 Hertz
40 ohms maximum, 22 Hertz

600 watts rms (2 hours of 6dB crest factor pink noise, 40 - 400 Hertz)
recommended amplifier power capability- 1100 watts rms maximum into 4 ohms (per LF-4115)

DSP configurations are available at www.qscaudio.com. Parameters for alternative processing hardware are available
upon request.

2

) stranded wire. Four terminals: (two INPUT and two par-

allel OUTPUT).

formers. High excursion/low distortion design, with extremely high power handling, and low thermal and port com­pression.

Enclosure: Quasi B4 alignment, ported enclosure with fully flared ports, low turbulence symmetrical port design, tuned to 36

Hertz, constructed of medium density fibreboard and heavily braced. Features vandal resistant woofer mounting bolts.

Size: 30” wide X 18” high X 20” deep (762mm X 457mm X 508mm)

Weight: 96 lbs. shipping, 83 lbs. net (44/38 kg.)

SPL and Impedance vs. Frequency

SPL 2pi

SPL (dB)

SPL 4pi

Impedance (ohms)

Impedance

Frequency (Hertz)

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

©2004 “QSC” and the QSC logo are registered with the U.S. Patent and Trademark Office.

Kapton® is a registered trademark of E.I. du Pont de Nemours and Company.

1675 MacArthur Blvd., Costa Mesa, CA, 92626 EE.UU.
Número principal [phone] Ventas y Comercialización [phone] o línea sin costo (sólo para
EE.UU.) [phone]
Servicio al cliente [phone] o gratis (sólo EE.UU.) [phone]

Manual del usuario de los sistemas de altavoces para salas de cine

Altavoz de baja frecuencia LF-4115

Introducción

La caja de baja frecuencia de 15” (381 mm) del altavoz LF-4115 está diseñada específica­mente para aplicaciones cinematográficas. El cumplimiento de los requisitos de las aplica­ciones cinematográficas referentes a una respuesta extendida de baja frecuencia, es lo que
distingue al altavoz LF-4115 de otros sistemas woofer tipo “rock-and-roll” más convenciona­les. El altavoz LF-4115 cubre un intervalo de frecuencia de 33 Hertzios a 1200 Hertzios,
dependiendo de los requisitos del sistema de alta frecuencia.

El transductor adaptado de 400 vatios y 15” se desarrolló específicamente para su uso en
salas de cine. Cuenta con una bobina de voz de 4” (100 mm), un imán cerámico de 120 onzas
(3.4 kg) y un polo multiventilado para asegurar una operación fría. Las temperaturas más
frías aumentan la vida útil del transductor y disminuyen el problema de compresión de la
potencia a niveles altos de potencia. Un polo proyectado asegura que la bobina de voz opere
en un campo magnético simétrico, reduciendo la deformación armónica de segundo orden.
La suspensión y la bobina de voz del transductor se han diseñado para brindar una baja dis­torsión y graves de alto impacto a alta potencia.

La caja está construida de paneles de cartón duro mediano de alta calidad con soportes de
refuerzo en los seis paneles. Ambas aberturas del puerto, la interna y la externa, están total­mente redondeadas, lo cual asegura un flujo de aire uniforme a mayores niveles de poten­cia, evitando turbulencia audible en el puerto.

Puntos de montaje para el sistema de

alta frecuencia o el sistema de fre-

cuencia media alta

Los puertos de graves están separados simétricamente a cada lado del transductor, haci­endo que la presión interna sea más uniforme a través de la superficie posterior del trans­ductor. Esto evita que el cono sea desplazado de un lado a otro por fuerzas no equilibradas,
reduciendo la probabilidad de impulsar la bobina de voz fuera del centro del espacio a altos
niveles de potencia.

Tres tuercas en T en la parte superior de la caja permiten el montaje fácil del sistema de alta
frecuencia HF-75 o del sistema de frecuencia media alta MH-1063, ambos de QSC.

La caja no esta diseñada para montarse suspendida, en voladizo ni sobre
arneses. No suspenda esta caja, no la monte en voladizo ni sobre arneses.

Este producto es capaz de producir niveles de presión del sonido que
pueden causar daños permanentes al oído humano. Siempre mantenga los
niveles de presión del sonido en un área de audición con un nivel menor
que el que provoca daños al oído humano.

Instale de acuerdo con las instrucciones de QSC Audio Products y de un
ingeniero profesional con la debida licencia. Sólo use piezas, montajes,
accesorios O soportes especificados por QSC Audio Products, Inc. Refiera
todo el servicio a personal calificado. Cuando el aparato haya sido dañado
de alguna manera, es necesario proporcionarle servicio.

¡ADVERTENCIA! Antes de colocar, instalar, montar o suspender cualquier
producto de altavoz, inspeccione todo el equipo físico, la suspensión, los
armarios, los transductores, los soportes y el equipo asociado para detec­tar la existencia de daños. Cualquier componente faltante, corroído, defor­mado, o sin carga nominal podría reducir significativamente la resistencia
de la instalación, la colocación o la configuración. Cualquier condición de
este tipo reduce gravemente la seguridad de la instalación y debe corre­girse de inmediato. Use sólo herraje que esté clasificado para las condi­ciones de carga de la instalación y cualquier posible carga excesiva a
corto plazo inesperada. Nunca exceda el valor nominal del equipo físico ni
del dispositivo. Consulte a un ingeniero profesional con la debida licencia
cuando surjan dudas o preguntas referentes a la instalación física del
equipo.

QSC® es una marca comercial registrada de QSC Audio Products, Inc.

“QSC” y el logotipo de QSC están registrados con la Oficina de Patentes y Marcas

© Derechos de autor 2004, QSC Audio Products, Inc.

Comerciales de los Estados Unidos

TD-000171-00 rev. C

Conexiones

Conexión normal

El altavoz LF-4115 tiene terminales de tor­nillo de barra protectora para su conexión.
Los terminales aceptan cableado trenzado
de hasta #10 AWG (5.3 mm
oces. Use el alambre del calibre más
grande y de la longitud más corta posible
en cualquier instalación. Observe las mar­cas de polaridad y mantenga la polaridad
uniforme en todo el sistema para obtener
el mejor rendimiento.

2

) para altav-

Ejemplo de una conexión normal:

Amplificador con capacidad
de accionamiento de cargas
de 4 ohmios

Conexión en paralelo de un segundo
LF-4115

Los terminales marcados SALIDA se
pueden usar para conectar en paralelo otro
altavoz LF-4115. Conecte los cables como
se muestra en la ilustración, a la derecha.

Ejemplo de conexión en paralelo:

Amplificador con capacidad de
accionamiento de cargas de 2 ohmios