Memphis MJM844 MOJO Series 8-inch Subwoofer Instruction Manual

1. Introduction

This manual provides essential information for the proper installation, operation, and maintenance of your Memphis MJM844 MOJO Series 8-inch subwoofer. The MJM844 is designed to deliver powerful low-frequency sound in a compact form factor, featuring Direct Vent Voice Coil (DVVC) cooling technology for enhanced thermal management.

2. What's in the Box

Verify that all items are present before proceeding with installation:

• One (1) 8-inch Subwoofer
• One (1) Rubber trim ring/gasket (pre-installed)
• One (1) User Manual (this document)

3. Key Features

The Memphis MJM844 subwoofer incorporates several design elements for performance and durability:

• Vented cast aluminum basket for structural integrity and cooling.
• Fiberglass reinforced cone for rigidity and accurate bass reproduction.
• Stitched foam surround for durability and excursion control.
• Heat dissipating aluminum heat sink for improved thermal management.
• 4-layer copper 2-inch voice coil for power handling.
• DVVC (Direct Vent Voice Coil) Cooling technology.

4. Specifications

Detailed technical specifications for the MJM844 subwoofer:

5. Installation and Wiring

Proper installation is crucial for optimal performance and longevity of your subwoofer. It is recommended that installation be performed by a qualified car audio professional.

5.1 Enclosure Requirements

The MJM844 subwoofer requires a suitable enclosure for proper operation. Consult with a car audio specialist or refer to Memphis Audio's official documentation for recommended enclosure types (sealed, ported) and volume specifications. Ensure the enclosure provides adequate clearance for the subwoofer's mounting depth (5.75 inches) and cut-out diameter (7.32 inches).

5.2 Mounting the Subwoofer

1. Carefully place the subwoofer into the prepared cut-out in the enclosure.
2. Align the mounting holes on the subwoofer frame with the pre-drilled holes in the enclosure.
3. Secure the subwoofer using appropriate screws, ensuring even pressure around the frame. Do not overtighten.

Image: Front view of the Memphis MJM844 8-inch subwoofer, showcasing the cone, surround, and MOJO branding.

5.3 Wiring Connections

The MJM844 features dual 4-ohm voice coils. Proper wiring is essential to match the subwoofer's impedance to your amplifier's capabilities. Incorrect wiring can lead to amplifier damage or poor performance. Common wiring configurations include:

• Parallel Wiring: Connects both 4-ohm voice coils in parallel for a 2-ohm total impedance.
• Series Wiring: Connects both 4-ohm voice coils in series for an 8-ohm total impedance.

Always refer to your amplifier's manual for stable impedance loads and consult wiring diagrams specific to dual voice coil subwoofers. Ensure all connections are secure and properly insulated to prevent short circuits.

Image: Rear view of the Memphis MJM844 subwoofer, highlighting the voice coil terminals for wiring connections.

Image: Side profile of the Memphis MJM844 subwoofer, illustrating its overall depth and cast basket structure.

6. Operation

Once installed and wired correctly, follow these guidelines for operating your subwoofer:

• Break-in Period: Allow a break-in period of several hours of moderate listening before operating the subwoofer at high volumes. This allows the suspension components to loosen and perform optimally.
• Amplifier Gain Setting: Set your amplifier's gain correctly to match the output voltage of your head unit. Incorrect gain settings can lead to distortion and potential damage to the subwoofer or amplifier.
• Crossover Settings: Use a low-pass filter (LPF) to ensure the subwoofer only reproduces low frequencies. A typical LPF setting for an 8-inch subwoofer might be between 60Hz and 100Hz, depending on your system and preferences.
• Subsonic Filter: If your amplifier or head unit has a subsonic filter, enable it to protect the subwoofer from playing frequencies below its resonant frequency, which can cause excessive excursion and damage.
• Listen for Distortion: If you hear any distortion, reduce the volume immediately. Distortion indicates that the subwoofer or amplifier is being overdriven.

7. Maintenance

The Memphis MJM844 subwoofer requires minimal maintenance to ensure long-term performance:

• Cleaning: Periodically wipe the subwoofer cone and surround with a soft, dry cloth to remove dust and debris. Avoid using harsh chemicals or excessive moisture.
• Inspection: Regularly inspect the subwoofer for any signs of damage to the cone, surround, or dust cap. Check wiring connections for tightness and corrosion.
• Environmental Factors: Protect the subwoofer from extreme temperatures, direct sunlight, and moisture, which can degrade materials over time.

8. Troubleshooting

If you experience issues with your subwoofer, refer to the following common troubleshooting steps:

If these steps do not resolve the issue, contact Memphis Audio customer support or a qualified service technician.

9. Warranty Information

The Memphis MJM844 subwoofer comes with a Limited Warranty. Specific terms and conditions of the warranty, including duration, coverage, and claim procedures, are typically provided with the product or available on the manufacturer's official website. Please retain your proof of purchase for warranty claims.

10. Customer Support

For technical assistance, service, or further information regarding your Memphis MJM844 subwoofer, please contact Memphis Audio customer support. You can typically find contact details, FAQs, and additional resources on the official Memphis Audio website.

Website: www.memphiscaraudio.com (Example link, actual link may vary)