QSC LF-2215 User Manual

Cinema Low Frequency
Loudspeaker

User Manual

LF-2215 Low Frequency Loudspeaker

®

TD-001558-01-B

*TD-001558-01*

EXPLANATION OF SYMBOLS

The term “WARNING!” indicates instructions regarding personal safety. If the instructions are not followed the result may be bodily injury or death.

The term “CAUTION!” indicates instructions regarding possible damage to physical equipment. If these instructions are not followed, it may result in
damage to the equipment that may not be covered under the warranty.

The term “IMPORTANT!” indicates instructions or information that are vital to the successful completion of theprocedure.

The term “NOTE” is used to indicate additional useful information.

NOTE: The intent of the lightning flash with arrowhead symbol in a triangle is to alert the user to the presence of un-insulated
“dangerous” voltage within the product’s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to
humans.

NOTE: The intent of the exclamation point within an equilateral triangle is to alert the user to the presence of important safety, and
operating and maintenance instructions in this manual.

IMPORTANT SAFETY INSTRUCTIONS

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any ventilation opening. Install in accordance with the manufacturer’s instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.

9. Only use attachments/accessories specified by the manufacturer.

10. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as
power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to
rain or moisture, does not operate normally, or has been dropped.

11. Adhere to all applicable, local codes.

12. Consult a licensed, professional engineer when any doubt or questions arise regarding a physical equipment installation.

13. Do not use any aerosol spray, cleaner, disinfectant or fumigant on, near or into the apparatus. Clean only with a dry cloth.

14. Do not submerge the apparatus in water or liquids.

15. Keep ventilation opening free of dust or

other matter.

Maintenance and Repair

WARNING!: Advanced technology, e.g., the use of modern materials and powerful electronics, requires specially
adapted maintenance and repair methods. To avoid a danger of subsequent damage to the apparatus, injuries to persons
and/or the creation of additional safety hazards, all maintenance or repair work on the apparatus should be performed only
by a QSC authorized service station or an authorized QSC International Distributor. QSC is not responsible for any injury,
harm or related damages arising from any failure of the customer, owner or user of the apparatus to facilitate those repairs.

TD-001558-01-B

2

Introduction

The LF-2215 dual 15” (381 mm) low frequency enclosure is designed specifically for cinema
applications. Meeting cinema requirements for extended low frequency response differentiates the
LF-2215 from more conventional “rock-and-roll” woofer systems. The LF-2215 covers the frequency
range from 38 to 1500 Hz, depending upon the high frequency system requirements. With its tight
spacing between woofers, the LF-2215 offers improved coupling and keeps coverage angles wide over
a greater frequency range than more widely spaced designs.

The 550 watt, 15” transducers are well suited for cinema use. They feature 3” (76 mm) voice coils 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.

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 MH-1060 mid-high
frequencysystem.

30 in

(762 mm)

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’s instructions and a licensed, professional engineer. Only use
attachments, mounts, accessories, or brackets specified by QSC. 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..

35 in

(889 mm)

TD-001558-01-B

20 in

(508 mm)

— Figure 1 —

3

Connections

Normal Connection

Refer to Figure 2

The LF-2215 has barrier strip screw terminals for connection. The terminals accept up to
#10 AWG (5.3 mm2) stranded loudspeaker wiring. Use the largest wire size and shortest wire
length possible for the application. Observe the polarity markings and keep polarity consistent
throughout the system for best performance.

Parallel Connection of Second LF-2215

Refer to Figure 3

The terminals labeled OUTPUT may be used to connect another LF-2215 in parallel.
Connect the wires as shown in the illustration, at right. Note: If the LF-2215’s internal wiring
has been modified in any way, this may not function. If this is the case, remove the terminal
cup and verify the presence of the factory yellow jumper and blue jumper wires; correct as
required or have the loudspeaker serviced.

Amplifier capable of
driving 4 ohm loads

— Figure 2 —

Amplifier capable of
driving 2 ohm loads

Individual Transducer Connection (requires modification)

Refer to Figure 4.

The transducers are wired in parallel inside the enclosure. If individual transducer connection
is required, remove the terminal cup and remove the yellow and the blue jumper wires that are
connected between the INPUT and OUTPUT terminals. Replace the terminal cup and mark the
enclosure with a note of the modification.

CAUTION!: Requires removal of terminal cup and removing both the yellow
and the blue jumper wires that connect the INPUT and OUTPUT terminals.

— Figure 3 —

— Figure 4 —

TD-001558-01-B

4

Specifications

(subject to change without notice)

Freq. Range 37 - 3500 Hz (-6 dB)

30-4000 Hz usable range (-10 dB)

Nominal Coverage 130 Horizontal x 50 Vertical at 600 Hz

Max. Output: 132 dB SPL calculated peak, 1 meter, half space, at rated rms power with 6 dB crest factor pink noise input, 30 - 300 Hertz. Based on

Impedance: 4 ohms nominal

Maximum Input Power 600 W RMS (2 hours of 6 dB crest factor pink noise, 30-300 Hertz) Based on nominal impedance.

Sensitivity 98 dB, 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.

Connectors Barrier strip screw terminals accept up to #10 AWG stranded wire.

Transducers Two 15 in (381 mm) high-efficiency low-frequency transducers featuring vented 3” (76 mm) copper voice coils on polyimide film tape

Enclosure Quasi B4 alignment, ported enclosure with fully-flared ports, low-turbulence symmetrical-port design, tuned to 36 Hertz, constructed of

Size (HWD) 35 in x 30 in x 20 in (889 mm x 762 mm x 508 mm)

Weight

NET

Shipping

nominal impedance.
126 dBA SPL calculated maximum continuous, 1 meter. The dBA scale is typically used to identify sound sources which can cause

permanent hearing loss.

Recommended amplifier power capability- 1200 W RMS maximum into 4 ohms (per LF-2215)

Four terminals: (two INPUT and two PARALLEL OUT).
Transducers are internally wired in parallel. For independent transducer connection, remove blue jumper wire and yellow jumper wire on

internal-side of terminal cup and mark enclosure accordingly..

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

medium-density fiberboard and heavily-braced. Features vandal resistant woofer mounting bolts.

172 lb (78 kg)
195 lb (88 kg)

TD-001558-01-B

5

®

Mailing Address:

QSC, LLC

1675 MacArthur Boulevard

Costa Mesa, CA 92626-1468 U.S.

Telephone Numbers:

Main Number: +1.714.754.6175

Sales & Marketing: +1.714.957.7100 or toll free (U.S. only) 800.854.4079

Customer Service: +1.714.957.7150 or toll free (U.S. only) 800.772.2834

Facsimile Numbers:

Sales & Marketing FAX: [phone]

Customer Service FAX: [phone]

World Wide Web:

www.qsc.com/cinema/

E-mail:

[e-mail]

[e-mail]

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Alltrademarks are the property of their respective owners.

http://patents.qsc.com.