User manual JBL P-1000

[. . . ] The size of the box and tuning frequency of port tubes in vented enclosures dictate the lowfrequency performance and output capability of your system. The flexibility designed into the Power Series subwoofers lets them make tons of bass in small sealed, vented and bandpass enclosures. They will also work well in infinite baffle applications where there is no space or budget to build a box. Be aware that infinite baffle or "free air" mounting will reduce the power handling and the low-frequency response of a subwoofer. [. . . ] For example, a 10" x 10" x 20" box would be susceptible to standing waves that may cancel some frequencies and add to cabinet resonance. A better alternative would be 18" x 11" x 10". It is recommended that 3/4" (19mm) MDF be used to build the enclosure. Particle board is acceptable, but it is more difficult to work with. Enclosures for 12" and larger subwoofers, or small subwoofers, driven by high power amplifiers should be constructed out of 1" (25mm) material. 3. All joints should be glued and screwed; do not use nails. "Deck" or "Zip" screws are recommended since they have coarse threads for better grip and don`t require pre-drilling holes. Once the box has been tested, it should be sealed with caulk around all interior joints. Apply a 1" thick sheet of polyfill (available at fabric and craft stores) to all inside walls except the wall where the subwoofer is mounted. If this is not done, increase the recommended box volume by 10 percent. Use PVC or ABS pipe (cardboard tubing is acceptable if the walls are over 1/16" thick). Keep in mind the openings at either end of the port must be at least one port diameter away from any obstructions inside or outside of the box. Minimum recommended port size is as follows: 8" 10" 12" 15" Subwoofer Subwoofer Subwoofer Subwoofer ­ ­ ­ ­ 2" 3" 3" 4" Tools you will need: · Straight-edge · Saw (circular or table) · Screwdriver (powered or screwdriver bits in a variablespeed drill are best) · Sabre saw or keyhole saw (to cut hole for woofer) · Measuring tape · Soldering iron and solder · Wire cutters/strippers · Utility knife (to cut carpet) · Pencil Materials: · 3/4" or thicker MDF · Caulk · PVC or ABS pipe · Deck screws · Carpet · Carpet Adhesive (aerosol-type works well) · Speaker wire (12 or 16 gauge for woofers) Take your time and mark the wood carefully before making any cuts. The old adage "measure twice and cut once" definitely applies here. Use the straightedge to make sure your lines are straight, and clamp it to the wood to use it for guiding the saw if you are using a circular saw. This will get you the straightest edges, the best fit and the best sound. Possible Perils Pertaining To Power Handling The power-handling capability of any woofer is related to both its ability to dissipate heat, and the maximum excursion limits of its cone. Power handling for subwoofers is directly related to the type of enclosure that is chosen. The JBL Power Series subwoofers are designed to meet their power ratings in properly designed, sealed, vented, and bandpass boxes. Please be aware of the following: · Voice-coil overheating and burning is typically caused by overdriving an amplifier into "clipping" This damages more . Damage occurs because the amplifier is too small rather than too large. Bass that sounds broken up and distorted at higher volumes usually indicates that the amplifier is being asked to deliver power beyond its capabilities. · Sharp "popping" sounds coming from a woofer indicate that the voice coil is "bottoming out" or hitting the back of the motor structure. Either your sealed box is too big or leaking air, the port tuning frequency of a vented box is too high or your amp may be overpowering the woofer. [. . . ] The following are not covered: Damage caused by accident, misuse, abuse, product modification or neglect; damage occurring during shipment; damage from failure to follow instructions contained in the instruction manual; damage resulting from the performance of repairs by someone not authorized by JBL; damage caused by installation of parts that do not conform to JBL specifications; units used for commercial or business use; any claims based on misrepresentations by the seller; products sold on an "as-is" or final sale basis; or the cost of installing, removing, or reinstalling the unit. JBL's liability is limited to the repair or replacement, at our option, of any defective product and shall not include incidental or consequential damages. JBL reserves the right to replace a discontinued model with a comparable model. Any replacement units or parts may be new or rebuilt. [. . . ]