JBL P1242, P1042, P1040, P1240 User Manual

Automotive Subwoofers Owner’s Manual P1040 P1042 P1240 P1242
Thank you for purchasing a new JBL GTp subwoofer. Subwoofer installation requires woodworking skills and some experience disassembling and reassembling automotive interiors. If you lack the tools or necessary skills, have your subwoofer installed by an authorized JBL dealer.
Warning: Playing loud music in an automobile can permanently damage your hearing as well as hinder your ability to hear traffic. We recommend listening at low levels while driving. JBL accepts no liability for hearing loss, bodily injury or property damage resulting from use or misuse of this product.
GTp subwoofers are optimized to perform best in small, sealed, vented and prefabricated bandpass enclosures. While infinite-baffle mounting of GTp subs is possible, power handling will be greatly compromised because there’s no enclosed volume of air to prevent the speaker’s cone from moving past its limit. For this reason, we do not recommend infinite-baffle mounting for GTp subwoofers.
You should choose the enclosure you will use based on the type of music you listen to, how much amplifier power you will use for the subwoofer and how much space inside the vehicle you can devote to a subwoofer enclosure.
Because a sealed enclosure provides the most control over the woofer’s movement, a woofer mounted in a sealed enclosure will handle more power than a woofer mounted in another enclosure type. Sealed enclosures provide more accurate sonic reproduction than other enclosure types, so they are well suited to all types of music. Sealed-enclosure construction is straightforward and there are
many prefabricated sealed enclosures available. An optimum sealed enclosure is always smaller than other types of enclosures optimized for a particular speaker, so they require the smallest amount of space inside the vehicle.
Vented enclosures provide better efficiency in the 40Hz –50Hz range but this efficiency comes at the expense of sound in the lowest octave (below 40Hz) and at the expense of some control and power handling. If you are using a small amplifier, a vented box will provide more bass output from less power. Vented enclosures are also well suited to a variety of music types. Because vented enclosures require the volume of the enclosure and the size of the port to have a specific relationship with the characteristics of the woofer, the enclosure must be built exactly to the specifications provided. While there are some prefabricated vented boxes available, matching a prefabricated box to a particular woofer is difficult. If you wish to use a vented enclosure, we strongly recommend having your authorized JBL dealer build it or verify that
your design is correct if you wish to build it yourself. An optimum vented enclosure is always larger than the optimum sealed box for the same woofer and will require more space inside the vehicle.
Bandpass enclosures often provide the most output available from any amplifier and subwoofer combination at the expense of sonic accuracy. If sheer SPL (sound-pressure level) is what you desire most, choose a bandpass enclosure. Bandpass-enclosure design is very tricky and the aid of a computer and enclosure design-software is necessary. If you are an experienced installer or have some woodworking experience, you may wish to build the enclosure described in the enclosure design sheet included with this woofer. Fortunately, there are many prefabricated bandpass boxes available and they are all optimized to extract the most output possible from any woofer. Bandpass enclosures can be quite large and may require a lot of space inside your vehicle.
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Choosing an Enclosure JBL Pro Power GTp Series
03
JBL GTp subwoofers are available in two different congurations: single 4-ohm voice coil and dual 4-ohm voice coils. Depending on the amplifier you are using, you may use either single-voice-coil or dual-voice-coil subwoofers in singles or multiples to maximize the power available from your amplifier. To achieve the maximum amplier output possible, you should design a speaker system that provides the lowest impedance that your amplier is rated to drive safely. When designing a subwoofer system, consider the following rules:
1. Dont mix different subwoofer or enclosure types in the same system (use all single-coil woofers or all dual-coil woofers).
2. You may connect the coils of a dual-voice-coil woofer in series, but NEVER connect separate woofers in series. Because the amplifier-damping factor (the ampliers ability to control the motion of the woofer) is expressed as a ratio of terminal impedance (the sum of speaker impedance, wire resistance and the D.C. resistance of any crossover coil connected to the woofer) to amplier-output impedance, connecting separate woofers in series reduces the damping factor of the amplier to a value less than 1. This will result in poor transient response.
3. You must use both coils of a dual-voice-coil woofer connected either in series or in parallel.
4. Most ampliers deliver exactly the same amount of power bridged into a 4-ohm load as they do running a 2-ohm stereo load.
To design a subwoofer system that maximizes available amplifier power, keep the following rules in mind:
1. The total system impedance of woofers in parallel = 1/(1/w
1
+ 1/w2+ 1/w3...), where w is the nominal impedance of the woofer.
2. The total system impedance of voice coils (or woofers) in series = w1+ w2+ w3...
The diagrams below and at right show parallel and series speaker connections.
Figure 1. Parallel connection
Figure 2. Series connection
POS ( + )
NEG ( – )
RED STRIPE POS ( + )
BLACK STRIPE NEG ( – )
POS ( + )
NEG ( – )
RED STRIPE POS ( + )
BLACK STRIPE NEG ( – )
Connecting Your Subwoofer to Your Amplifier JBL Pro Power GTp Series
JBL Consumer Products • 250 Crossways Park Drive, Woodbury, NY 11797 1-800-336-4JBL (4525) www.jbl.com
©2000 JBL, Incorporated • JBL is a registered trademark of JBL, Incorporated Made in USA Printed in USA 3/00 Part No. P1040-42/P1240-42OM
P1040 P1042 P1240 P1242
10" Automotive subwoofer 10" Automotive subwoofer, 12" Automotive subwoofer 12" Automotive subwoofer,
dual voice coil dual voice coil
Power handling (peak) 1400 Watts 1400 Watts 1400 Watts 1400 Watts
Power handling (RMS) 350 Watts 350 Watts 350 Watts 350 Watts
Sensitivity (2.83V/1m) 92dB 92dB 93dB 93dB
Frequency response 20Hz – 500Hz 20Hz – 500Hz 18Hz – 500Hz 18Hz – 500Hz
Impedance 4 Ohms 2 or 8 Ohms 4 Ohms 2 or 8 Ohms
Mounting depth 5-1/8" (131mm) 5-1/8" (131mm) 5-11/16" (145mm) 5-11/16" (145mm)
Cut-out diameter 9-1/8" (232mm) 9-1/8" (232mm) 11-1/8" (283mm) 11-1/8" (283mm)
Specifications JBL Pro Power GTp Series
Declaration of Conformity
We, Harman Consumer International
2, route de Tours 72500 Chateau-du-Loir FRANCE
declare in own responsibility, that the products described in this owners manual are in compliance with technical standards: EN 50081-1:1992 EN 50082-1:1992
Lutz Uphoff
Harman Consumer International
FRANCE. 2/00
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