JBL W12GTI Owners Manual English - Page 5

the other coil's magnetic gap. This will cause magnetic braking, which will slow the cone's motion and prevent damage due to overexcursion. For a GTi Series woofer, Xmax is determined by the amount of voice-coil overhang between the first and second top plates. See Figure 3. Thermal power handling is far superior to a conventional DVC woofer using voice coils of a similar diameter and length because Differential Drive provides twice the heat-dissipating surface area and two top plates to transfer heat to the magnet-cover fins. Figure 3. JBL dual-gap design Connecting Your Subwoofer to an Amplifier: Configuring the voice coils: Figure 4. Terminal locations TOP COIL IN GAP #1 DRIVES CONE FORWARD GAP #1 POLEPIECE GAP #2 BOTTOM COIL IN GAP #2 DRIVES CONE REARWARD CONE SPIDER 1st TOP PLATE MAGNET OVERHANG DETERMINES Xmax 2nd TOP PLATE ALUMINUM COVER PRO POWERTM Note: Unlike conventional DVC subwoofers, the two sets of terminals are configured so that both positive (+) terminals are on one side of the frame and both negative (-) terminals are on the other side. GTi Series subwoofers are shipped with terminal jumpers installed which configure the two 6-ohm voice coils in parallel for a 3-ohm load. Note: Both voice coils MUST be connected to the amplifier in series or parallel. Figure 5. Connecting the voice coils in parallel (3 ohms) Note: Connect the coils in parallel if you are connecting a single woofer to an amplifier. TERMINAL JUMPER INTACT RED TERMINAL TERMINAL JUMPER INTACT BLACK TERMINAL + Figure 6. Connecting the voice coils in series (12 ohms) TERMINAL JUMPER REMOVED RED TERMINAL + TERMINAL JUMPER REMOVED BLACK TERMINAL 05