User manual JBL GT 4-12

[. . . ] 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. [. . . ] 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 (soundpressure 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. 1 Connecting Your Subwoofer to Your Amplifier JBL GT4 Series JBL GT4 Series subwoofers are single 4-ohm voice coil. Depending on the amplifiers you are using, you may want to use either one or several subwoofers in the same enclosure to maximize the power available from your amplifiers. To achieve the maximum amplifier output possible, you should design a speaker system that provides the lowest impedance that your amplifier is rated to drive safely. When designing a subwoofer system, consider the following rules: 1. [. . . ] Parallel connection RED STRIPE POS ( + ) BLACK STRIPE NEG ( ­ ) POS ( + ) NEG ( ­ ) Figure 2. Series connection RED STRIPE POS ( + ) BLACK STRIPE NEG ( ­ ) POS ( + ) NEG ( ­ ) 2 Specifications JBL GT4 Series GT4-10 10" Automotive subwoofer Power handling (RMS) Power handling (Peak) Sensitivity (2. 83V/1m) Frequency response Impedance Mounting depth Cut-out diameter 250 Watts 1000 Watts 90dB 28Hz ­ 500Hz 4 Ohms 147mm 232mm GT4-12 12" Automotive subwoofer 250 Watts 1000 Watts 93dB 23Hz ­ 450Hz 4 Ohms 159mm 283mm GT4-15 15" Automotive subwoofer 250 Watts 1000 Watts 91dB 20Hz ­ 400Hz 4 Ohms 172mm 362mm Features, specifications and appearance are subject to change without notice. Declaration of Conformity JBL Consumer Products · 250 Crossways Park Drive, Woodbury, NY 11797 1. 800. 336. 4JBL (4525) · www. jbl. com Europe: 2, route de Tours. [. . . ]