1. Introduction
The JBL GT5-10D is a 10-inch dual-voice-coil subwoofer designed for car audio systems. It features a vented motor structure and is engineered to deliver robust bass performance. This manual provides essential information for the proper setup, operation, and maintenance of your subwoofer.

Figure 1: Front view of the JBL GT5-10D Subwoofer.
Key features include:
- 10-inch Dual 4 Ohm GT5 Series Subwoofer
- Peak Power Handling: 1100 watts
- RMS Power Handling: 275 watts
- Recommended power range: 150 - 275 watts RMS
- Polypropylene woofer cone material
- Rubber-coated tinsel leads for enhanced durability
- Proprietary steel frame
2. Setup and Installation
Proper installation is crucial for optimal performance and longevity of your JBL GT5-10D subwoofer. It is recommended that installation be performed by a qualified car audio professional.
2.1 Enclosure Requirements
The subwoofer is designed to operate within a suitable enclosure. Consult the specifications section for recommended enclosure volumes and types. Ensure the enclosure is robust and sealed properly to prevent air leaks, which can degrade sound quality.

Figure 2: Subwoofer dimensions for enclosure planning. The subwoofer measures 12"D x 12"W x 10"H.
2.2 Wiring the Dual Voice Coils
The GT5-10D features dual 4-ohm voice coils, allowing for flexible wiring configurations to match your amplifier's impedance requirements. Common configurations include:
- Parallel Wiring: Connect both voice coils in parallel for a 2-ohm load. This configuration typically draws more power from the amplifier.
- Series Wiring: Connect both voice coils in series for an 8-ohm load. This configuration draws less power and is suitable for amplifiers that are not 2-ohm stable.
Always refer to your amplifier's manual for compatible impedance loads and wiring diagrams. Incorrect wiring can damage both the subwoofer and the amplifier.

Figure 3: Side view of the subwoofer, illustrating the terminal connections for wiring.
2.3 Power Connection
Connect the subwoofer to a suitable amplifier using high-quality speaker wire. Ensure proper polarity (+ to + and - to -) to avoid phase issues that can negatively impact sound quality. The subwoofer is designed for wired connectivity, typically via RCA inputs from your head unit to the amplifier, and then speaker wire from the amplifier to the subwoofer.
3. Operating Instructions
Once installed and wired correctly, the JBL GT5-10D subwoofer will enhance your car audio system's bass response. The primary control for the subwoofer will be through your car's head unit or external amplifier controls.
3.1 Initial Power-Up and Adjustment
- Ensure all connections are secure before powering on your audio system.
- Start with the amplifier's gain control set to its minimum (lowest) setting.
- Play a piece of music with a good bass range.
- Slowly increase the amplifier's gain until the desired bass level is achieved without distortion.
- Adjust the low-pass filter (LPF) on your amplifier or head unit to blend the subwoofer's output seamlessly with your main speakers. A common starting point is around 80-100 Hz.
- If your system includes a phase control, experiment with 0° and 180° settings to find the one that provides the most impactful and coherent bass.
While the product specifications mention "Touch" as a control method, for a passive subwoofer like the GT5-10D, this typically refers to controls on the connected amplifier or head unit, not directly on the subwoofer itself.
4. Maintenance
The JBL GT5-10D subwoofer is built for durability, but proper care will ensure its long-term performance.
- Cleaning: Use a soft, dry cloth to wipe down the subwoofer cone and surround. Avoid using harsh chemicals or excessive moisture.
- Inspection: Periodically check the speaker terminals and wiring for any signs of corrosion or loose connections. Ensure the rubber-coated tinsel leads are intact, as they protect against wear.
- Environmental Factors: While designed for car environments, extreme temperatures and direct sunlight can affect performance over time. Ensure adequate ventilation around the subwoofer.
5. Troubleshooting
If you experience issues with your JBL GT5-10D subwoofer, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| No Sound from Subwoofer |
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| Distorted or "Muddy" Bass |
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| Weak or Lackluster Bass |
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If problems persist, consult a professional car audio technician.
6. Specifications
| Feature | Detail |
|---|---|
| Model Name | GT5-10D |
| Speaker Type | Subwoofer |
| Subwoofer Diameter | 10 Inches |
| Speaker Maximum Output Power | 1100 Watts (Peak) |
| RMS Power Handling | 275 Watts |
| Impedance | Dual 4 Ohms (can be wired to 2 or 8 ohms) |
| Woofer Cone Material | Polypropylene |
| Product Dimensions | 12"D x 12"W x 10"H |
| Item Weight | 13.2 Pounds |
| Connectivity Technology | Wired (RCA or 3.5mm audio jack to amplifier) |
| Manufacturer | Harman Kardon |
| Item Model Number | GT5-10D |
| UPC | 050036931007 |
7. Understanding Your Subwoofer (Video)
This video provides additional insights into the design and technology behind JBL and Infinity speakers, including concepts relevant to your subwoofer's performance, such as materials and cone design.
Video 1: JBL & Infinity Speakers and Subwoofers: Bigger Bass. This video explains the importance of speaker materials and cone design for improved bass response and durability.
8. Warranty and Support
The JBL GT5-10D subwoofer comes with a standard manufacturer's warranty. Please refer to the warranty documentation included with your product for specific terms, conditions, and registration information. For technical support or service inquiries, please contact JBL customer service or visit the official JBL website.
Manufacturer: Harman Kardon





