1. Introduction
Thank you for choosing the Memphis Audio MJM812 8" MOJO Subwoofer. This manual provides essential information for the proper installation, operation, and maintenance of your new subwoofer. The MJM812 features Memphis FLEX technology, allowing for selectable impedance between 1Ω or 2Ω, and is designed to deliver powerful bass performance in a compact form factor.
Figure 1.1: Front view of the Memphis Audio MJM812 MOJO Subwoofer.
2. Key Features
- Memphis FLEX Technology: Allows selection between an impedance of 1Ω or 2Ω for versatile amplifier matching.
- Compact Power: Delivers intense bass performance in both 6.5” and 8” versions.
- Folded V-Groove Surround: Increases excursion without sacrificing effective surface area, enhancing bass output.
- Double Stitched V-Groove Rubber Surround: Ensures durability and consistent performance.
- Lightweight Ultra-Rigid Glass Fiber Dustcap: Contributes to precise and responsive bass reproduction.
3. Setup and Installation
Proper installation is crucial for optimal performance and longevity of your subwoofer. It is highly recommended that installation be performed by a qualified professional.
3.1. Choosing an Enclosure
The MJM812 subwoofer is designed to perform well in various enclosure types, including sealed and ported designs. Consult with a car audio specialist or refer to recommended enclosure specifications for your specific application to achieve the best sound quality and output.
3.2. Wiring and Impedance Selection
The Memphis FLEX technology allows you to configure the subwoofer for either 1Ω or 2Ω impedance. This flexibility enables compatibility with a wider range of amplifiers. Ensure your amplifier is stable at the selected impedance. Incorrect impedance matching can lead to amplifier damage or poor performance.
- 1Ω Wiring: Connect the included jumper wire between the two positive terminals and the two negative terminals to achieve a 1Ω load.
- 2Ω Wiring: Remove the jumper wire. Connect to either the 2Ω positive and negative terminals.
Figure 3.1: Side view of the subwoofer showing the wiring terminals and impedance selection options.
Figure 3.2: Detailed view of the wiring terminals, illustrating the 2Ω jumper connection.
3.3. Amplifier Selection
Select an amplifier that can provide sufficient power (RMS wattage) to the subwoofer at the chosen impedance. Overpowering or underpowering can lead to damage. Refer to the specifications section for recommended power handling.
4. Operating Instructions
Once installed, follow these guidelines for optimal operation:
- Break-in Period: Allow a break-in period of several hours of moderate listening before pushing the subwoofer to its limits. This allows the suspension components to loosen up and perform optimally.
- Gain Setting: Properly set the gain on your amplifier to match the output voltage of your head unit. Do not use the gain control as a volume knob; it should be set to prevent clipping.
- Crossover Settings: Use a low-pass filter (LPF) on your amplifier or head unit to send only low frequencies to the subwoofer. A typical crossover point for an 8-inch subwoofer is between 60Hz and 100Hz.
- Subsonic Filter: If your amplifier has a subsonic filter, set it slightly below your enclosure's tuning frequency to protect the subwoofer from over-excursion at very low frequencies.
- Listen for Distortion: If you hear any distortion, rattling, or unusual noises, immediately reduce the volume. Continued operation with distortion can cause permanent damage to the subwoofer.
Figure 4.1: Top view of the subwoofer cone and surround.
5. Maintenance
The Memphis Audio MJM812 subwoofer requires minimal maintenance to ensure long-lasting performance:
- Cleaning: Periodically wipe down 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, such as tears in the surround, dents in the dustcap, or loose connections. Address any issues promptly.
- Environmental Factors: Protect the subwoofer from extreme temperatures, direct sunlight, and excessive moisture, which can degrade materials over time.
6. Troubleshooting
If you experience issues with your subwoofer, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| No Sound from Subwoofer |
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| Distorted Sound |
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| Subwoofer Overheating |
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7. Specifications
| Specification | Value |
|---|---|
| Brand | Memphis |
| Model Number | MJM812 |
| Item Weight | 14.9 pounds |
| ASIN | B013SQ0B5Q |
| Date First Available | August 12, 2015 |
| Selectable Impedance | 1Ω or 2Ω |
| Customer Reviews (as of data capture) | 4.5 out of 5 stars (11 ratings) |
Note: Specifications are subject to change without notice.
8. Warranty and Support
Memphis Audio products are designed and manufactured to the highest quality standards. For specific warranty terms and conditions, please refer to the warranty card included with your product or visit the official Memphis Audio website. Keep your proof of purchase for warranty claims.
Memphis Audio Official Website: www.memphiscaraudio.com
You can also visit the Memphis Store on Amazon for more products and information: Memphis Audio Amazon Store
