[. . . ] Although these instructions explain in a general sense how to install Power Series loudspeakers, they may not show the exact installation methods for your particular vehicle. If you feel you lack the tools or necessary experience, ask your authorized JBL car-audio dealer about professional installation options. Installation Warnings and Tips · Always wear protective eyewear when using tools. [. . . ] · Turn off all audio systems and other electrical devices before you start. Disconnect the negative (­) lead from your vehicle's battery. When moving a speaker, always rest it with the cone or dome facing up. · Check clearances on both sides of a planned mounting surface before drilling any holes or installing any screws. · At the installation sites, locate and make a note of all fuel lines, hydraulic brake lines, vacuum lines and electrical wiring. Use extreme caution when cutting or drilling in and around these areas. Caution: In some cars, fuel tanks may be located directly beneath the rear deck. Check for adequate speaker-basket clearance before considering use of this location!Jumper Functions Lo Pass (Low Pass): You may engage or disengage the woofer low-pass filter with this jumper. Because the natural rolloff of the P-532 and the P-632 begin at a lower frequency than that of the P-432, this jumper should only be in the "on" position when the P-432 is being used. Twt Lvl (Tweeter Level): You may attenuate the level of the tweeter's output using this jumper. Twt Frq (Tweeter Frequency): Because the P-432 has usable frequency response higher than that of the P-532 or P-632, the optimum crossover frequency for the tweeter is slightly higher when the P-23t is used with the 4" woofer. Note: For the most accurate sound reproduction, the jumper positions should be set according to JBL recommendations. If an alternate setting better suits your preference or works better for your particular installation, you may position the jumpers as you like without affecting your warranty. Note: You may upgrade the performance of the P-432, P-532 or P-632 (when it is used as a multielement speaker) by utilizing the passive crossover contained in the P-Kit and leaving the tweeter mounted on the woofer. Figure 6b. Flush-mounting the P-23t (use a hole saw to cut a 1-9/16" hole in the mounting surface). Remove the top of the passive crossover by squeezing the sides and lifting off the top. [. . . ] Note: You may upgrade the performance of the P-432, P-532 or P-632 (when it is used as a multielement speaker) by utilizing the passive crossover contained in the P-Kit and leaving the tweeter mounted on the woofer. Figure 6b. Flush-mounting the P-23t (use a hole saw to cut a 1-9/16" hole in the mounting surface). Remove the top of the passive crossover by squeezing the sides and lifting off the top. Mount the crossover with screws or wire ties through the mounting holes. [. . . ]