User manual JBL GT102D

[. . . ] Warning: Playing loud music in an automobile can permanently damage your hearing as well as hinder your ability to hear traffic. JBL accepts no liability for hearing loss, bodily injury or property damage resulting from use or misuse of this product. Choosing an Enclosure GT Series subwoofers are optimized to perform best in small sealed, vented and prefabricated bandpass enclosures. While infinite-baffle mounting of GT Series subs is possible, power handling is 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 GT Series 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 can 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. 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. Don't mix different subwoofer or enclosure types in the same system (use all single-coil 4-ohm woofers, all singlecoil 8-ohm woofers, or all dual-coil woofers). 2. You may connect the coils of a dualvoice-coil woofer in series, but NEVER connect separate woofers in series. Because the amplifier-damping factor (the amplifier's 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 amplifier-output impedance, connecting woofers in series reduces the damping factor of the amplifier to a value less than 1. You must use both coils of a dualvoice-coil woofer either in series or in parallel. Most amplifiers 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. [. . . ] You must use both coils of a dualvoice-coil woofer either in series or in parallel. Most amplifiers 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/w1 + 1/w2 + 1/w3. . . ) where w is the nominal impedance of the woofer. [. . . ]