JBL W15GTi, W10GTi, W12GTi, MkII automotive User Manual

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JBL W15GTi, W10GTi, W12GTi, MkII automotive User Manual

GTi SERIES

W10GTi MkII

W12GTi MkII

W15GTi MkII

automotive subwoofer owner’s manual

THANK YOU

for choosing a JBL® GTi Series subwoofer. GTi subwoofers are designed to

provide maximum sound output in a variety of enclosure types while maintaining the superb sound quality associated with JBL. To ensure the best subwoofer performance, we strongly

recommend that installation be entrusted to a qualified professional. Although these instructions explain how to install a GTi Series subwoofer in

a general sense, they don’t show the specific installation procedures that may be required for your particular vehicle. If you feel you don’t have the necessary tools or experience, don’t attempt the installation yourself; rather, ask your authorized JBL dealer about professional-installation options.

INSTALLATION WARNINGS AND TIPS

WARNING

YOUR CAR AND BASS

POWER-HANDLING

Playing loud music in an automobile can

REPRODUCTION

LIMITATIONS

hinder your ability to hear traffic, as well

Depending on the size of the vehicle’s

The power-handling capacity of any

as permanently damage your hearing.

interior listening space, reproduced

subwoofer is related to the excursion

We recommend listening at low levels

frequencies below 80Hz may be boosted

limit of its suspension and its ability to

while driving. JBL accepts no liability for

by nearly 12dB per octave as frequency

dissipate heat. A speaker reaches its

hearing loss, bodily injury or property

decreases. This effect, commonly known

excursion-limited power-handling

damage resulting from use or misuse of

as transfer function, or cabin gain, plays

capacity when its suspension is

this product.

an important role in defining the in-car

stretched to its limit. The excursion

 

 

frequency response of your subwoofer.

curve shown on the Enclosure Design

 

 

It is displayed graphically, along with

Sheet (included with your woofer)

 

 

freespace response, on the enclosed

displays cone excursion at the input

 

 

data sheet for your GTi subwoofer.

power level required to drive the woofer

 

 

 

to maximum linear excursion (Xmax).

 

 

 

The input power shown may be used

 

 

 

as instantaneous input only.

 

 

 

 

 

 

 

 

Thermal power handling is determined by the amount of heat that may be dissipated by the driver’s voice coil. The power-handling rating assigned to your GTi Series subwoofer is its thermal-power-handling rating. This rating assumes a clean (unclipped) signal. A clipped waveform has much

higher average power, due to the longer duty cycle at the top and bottom of the waveform; it will heat the woofer’s voice coil faster than a clean signal and may damage the voice coil. A square wave has a 100% duty cycle and is extremely dangerous for any speaker. Audible distortion in the output of your woofer is an indication that your amplifier may be clipping, which could damage your speakers over time.

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CHOOSING AN ENCLOSURE

GTi Series subwoofers are optimized to perform best in small sealed, vented and bandpass enclosures. While infinitebaffle mounting of GTi Series subs is possible, power handling will be compromised since there will be no enclosed volume of air to help the speaker’s suspension control the motion of the woofer’s cone. For this reason, we do not recommend infinite-baffle mounting for high-power applications. You should choose the enclosure you’ll use based on the type of music you listen to, how much amplifier power you’ll use to drive the subwoofer, and how much space inside the vehicle you can devote to a subwoofer enclosure. If you’ll be using your GTi Series subwoofer for SPL competition, please see the document titled “GTi as SPL Competition Subwoofers” (included with your woofer).

Because a sealed enclosure provides the most control over the woofer’s movement, a woofer mounted in a sealed enclosure will handle more power at low frequencies 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. An optimum sealed enclosure is always smaller than other types of enclosures that are optimized for a particular speaker, so they require the least space inside the vehicle.

Vented enclosures provide better

 

 

efficiency in the 40Hz – 60Hz range,

the

 

but this efficiency comes at the expense

 

 

of sound output in the lowest octave

at

 

(below 40Hz) and at the expense of

 

 

some control and power handling below

what

 

box tuning. If you are using a small

or

 

amplifier, a vented box will provide

 

 

more bass output from less power.

aid

 

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

must

 

port to have a specific relationship with

 

 

the characteristics of the woofer, the

quite

 

enclosure must be built exactly to the

 

 

specifications provided. 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.

 

 

 

 

 

 

 

 

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