408/508 MANUAL.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 2 Table of Contents Welcome to Club GTi .........................................................................3 About this Manual ..............................................................................3 Autosound at its Best .........................................................................3 Designing Your System ......................................................................4 Component Placement.............................................
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 3 Welcome to Club GTi About This Manual Autosound at its Best Thank you for purchasing the finest Automotive Component Systems JBL has ever produced. As a GTi Competition Series owner, you are a member of a select group of people who enjoy the most advanced mobile audio products available. We call this group “Club GTi.
08/508 MANUAL.QXP 7/17/98 11:21 AM Page 4 minimizing stray magnetic fields, this closed circuit magnetic assembly design concentrates the magnetic field on the voice coil where it provides superior performance. In the woofer/midrange drivers, this high concentration of magnetic power is coupled to a 2" Edge-wound Aluminum Wire Voice Coil on a High Temperature Fiberglass Former.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 5 and high frequency transducers in a high quality system, we recommend you use either a high quality active crossover such as JBL’s GTX47, GTX4 or GTX2 to provide optimum matching to your subwoofer or woofer/midbass loudspeaker. If you prefer passive crossovers, we recommend that you use only high quality audiophile grade film-type capacitors and Low DCR inductors to get the most out of your system.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 6 Mounting Instructions 2. Pick a mounting location after reading the recommendations in the Component Placement section of this manual. 3. Installing the GTi System Crossover The GTi system crossover should be mounted securely to prevent damage to the crossover or possible loosening of wiring connections. Choose one of the crossover mounting methods and follow the directions below: 4. 5. 6. Remove the crossover board from the plastic case.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 7 Woofer/Midrange Driver Mounting Mounting the Woofer/Midrange to Stock Hole Locations 1. Access the stock speaker location and remove the stock speaker. The 408 and 508GTi include mounting ring adapters which allow the speaker to be mounted in standard 4" and 51/4" holes respectively. 2. Attach the mounting ring adapter to the stock location using four #8 x 11/4" screws as shown in Figure C. 3. Attach the foam gasket to the back of the woofer/midrange.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 8 GRILLE FRAME Logo Orientation on Grille The orientation of the logo on the metal grille relative to the grille frame can be adjusted. Simply remove the metal grille and reassemble the metal grille to the grille frame utilizing a different tab slot. Mounting the 408 and 508GTi Tweeter METAL GRILLE Figure E Note: The metal grille is designed so that it can be covered with grille cloth if desired.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 9 Tweeter Surface Angle Mounting Instructions D A a) Using the Surface Angle Mount Template at the back of the manual, drill two screw holes at the desired mounting location, making sure to choose the correct tweeter orientation. Secure the Surface Angle Mount Adapter with two 3⁄4" sheet metal screws as shown in Figure G. C B b) Secure the mounting plate to surface angle mount adapter using two 5⁄16" screws.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 10 Tweeter Flush Mounting Instructions a) Use a hole saw or other tool and the Flush Mount Template at the back of this manual to make a hole for the flush mount cup in the desired location. Secure the metal spring to the Flush Mount Cup using one metal spring screw as shown in Figure H. Tighten the screw only enough to keep the metal spring from falling off. b) Push the Flush Mount Cup with the metal spring into the hole that was cut in step a.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 11 Tweeter Flush Angle Mounting Instructions a) Follow steps a through c in the Tweeter Flush Mounting Instructions. E D b) Secure the Flush Angle Mount Adapter to the Flush Mount Cup using two 5⁄16" screws as shown in Figure J. c) Connect the 408 and 508GTi speaker wires (from the crossover) to the tweeter, observing correct polarity (see figure K for details).
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 12 Wiring Use 2-conductor stranded type, insulated wire to connect the 408 and 508GTi Woofer/Midrange and tweeter to the included crossover, and the crossover to the amplifier as shown in Figure K. A minimum wire gauge of 18AWG is recommended, with larger size suggested for wire runs longer than 10 feet.
408/508 MANUAL.QXP OdB –2dB –4dB 7/17/98 11:21 AM Page 13 Tweeter Level Adjustment Switch Figure M System Connections There are a variety of system options available with the 408 and 508GTi. The simplest configuration is to use the 408 and 508GTi full range. Although this will yield good sound, the best performance will be achieved in a high-end system which includes subwoofers and, optionally, midbass transducers.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 14 used and at or above 3.5kHz if you are using an 18 or 24dB per octave crossover. In this configuration, the crossovers supplied with the 408 and 508GTi are not used. For tweeter protection, a 1.5A fast acting fuse should be installed in series with the tweeter. The maximum recommended RMS amplifier power routed directly to the woofer/midrange is 150 watts for the 408GTi and 200 watts for the 508GTi.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 15 crossovers near wires carrying high currents such as battery cables or wires leading to ammeters or tachometers. Distortion is usually the result of overdriving one or more components in the system. The problem is most likely insufficient amplifier power, or improper setting of gain controls. Refer to the instructions which came with the electronics for assistance.
408/508 MANUAL.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 17 Thiele-Small Specifications: 408 GTi Free Air Resonance (Fs): 125Hz 508 GTi 100Hz Electrical Damping (Qes): 0.52 0.51 Mechanical Damping (Qms): 5.17 5.14 Total Damping (Qt): 0.47 0.4 Equivalent Volume of Compilance (Vas): 0.0388 cu. ft. (1.10 liters) 0.1059 cu. ft. (3.0 liters) Effective Cone Area (Sd): 9.3 sq. inches (0.0060 m2) 14.26 sq. inches (0.0092 m2) Center to Peak Linear Excursion (Xmax): 0.126 inches (3.2mm) 0.126 inches (3.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 18 Drill 11/32" (8.7mm) holes for wire feed through Drill 3/32" (2.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page 19 Drill 11/32" (8.7mm) holes for wire feed through TWEETER MOUNTING PLATE TEMPLATE Drill 3/32" (2.
408/508 MANUAL.
408/508 MANUAL.QXP 7/17/98 11:21 AM Page B JBL Consumer Products, Inc. 80 Crossways Park West Woodbury, NY 11797 8500 Balboa Blvd.
