User manual JBL GT1500

[. . . ] GRAND TOURING SERIES ® Automotive Subwoofers GT800, GT800d, GT1000, GT1000d, GT1200, GT1200d, GT1500, GT1500d Owner's Manual GENUINE JBL Enclosure Calculations and Building Boxes Thank you for choosing a JBL GT Series subwoofer. GT Series subwoofers are designed to suit a broad range of mobile audio applications and can be used in a wide variety of enclosure types to produce extended, powerful bass in a limited amount of vehicle space. To ensure maximum subwoofer performance, we strongly recommend that installation be left to a qualified professional. [. . . ] Vented and bandpass enclosures have the lowest amount of excursion for the amount of sound output. This is a result of port tuning reinforcing the sound output. Vented boxes will not provide adequate woofer control when driven below the port tuning range, so proper design is important. A fourth-order bandpass box will have the lowest overall cone excursion at the expense of limited bandwidth. In addition, there are a number of points you'll want to keep in mind as you construct an enclosure: 1. Use 3/4" (19mm) MDF (mediumdensity fiberboard) or marine birch plywood to build an enclosure. Enclosures for 12" and larger subwoofers, or small subwoofers driven by high-power amplifiers, should be constructed using 1" (25mm) material. 2. Seal all joints with glue and screws; do not use nails. We recommend "deck" or "zip" screws since they have coarse threads for better grip and don't require pre-drilling holes. Once the box has been tested, seal all interior joints with silicone caulk. Depending on the application, fill the enclosure according to the design you have chosen from the enclosed data sheet in one of three ways: zero-percent fill (i. e. , no fill), or 50-percent fill (i. e. , 1"thick polyfill sheets on all inside walls except where subwoofer is mounted), or 100-percent fill (i. e. , entire box is stuffed with loosely-packed polyester fiberfill). Keep in mind that the openings at either end of the port must be at least one port diameter away from any obstructions, including filling material inside or outside the box. Rectangular vents can be used as long as the crosssection area matches the recommended port-area values in the enclosed data sheet. 01 Power-Handling Limitations The power-handling capability of any woofer is related to both its ability to dissipate heat and the maximum excursion limits of its cone. Once the speaker's voice coil moves outside the magnetic gap, power can no longer be converted into motion, and all the amplifier's power is converted into heat in the voice coil. This voice-coil heating is the largest detriment to speaker longevity, so overexcursion (driving the speaker past Xmax) should be avoided. Since speaker-cone excursion is different for each type of enclosure, power handling is different for each enclosure. [. . . ] 2/98 JBL Consumer Products 250 Crossways Park Drive Woodbury, NY 11797 8500 Balboa Blvd. Northridge, CA 91329 800-336-4JBL (4525) www. jbl. com CEL EB RAT I NG Part No. GTAUTOSUBOM Made in USA 0 YEAR S 5 [. . . ]