1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of the Audison AP BMW S8-4 Prima Series 8-inch (200mm) Subwoofer. This subwoofer is specifically designed for direct replacement of OEM speakers in BMW vehicles, optimizing performance within the factory under-seat enclosure.
Image 1.1: Front view of the Audison AP BMW S8-4 Prima Series Subwoofer.
2. What's in the Box
Carefully unpack the contents and ensure all items are present:
- Audison AP BMW S8-4 Subwoofer(s)
- Two (2) 5 mm polyurethane gaskets
- Crossover (if applicable to your system configuration)
- Mounting screws
- User manual (this document)
- Warranty information
Image 2.1: Product packaging for the Audison AP BMW S8-4 Subwoofer.
Image 2.2: Included 5mm polyurethane gaskets for optimal fit.
3. Features
The Audison AP BMW S8-4 Subwoofer incorporates several design elements for enhanced performance and compatibility:
- Neodymium Magnetic Group: Maximizes performance while minimizing bulk and weight.
- BMW-Mini Optimized Electroacoustic Parameters: Engineered to deliver powerful and clear low frequencies, utilizing the acoustic load provided by the factory enclosure.
- 38 mm Voice Coil: Wound on an aluminum support for significant power dissipation and stability, even during high excursions.
- ABS Plastic Basket: Reinforced with fiberglass for durability and minimal installation depth.
- Front Magnet Design: Contributes to a minimal installation depth, ensuring compatibility with the entire range of BMW under-seat enclosures.
- 4 Ohm Impedance: The S8-4 model is designed with a 4 ohm impedance, suitable for system configurations where amplifiers can be bridged to deliver higher power.
Image 3.1: View of the subwoofer cone and central voice coil area.
4. Specifications
| Specification | Value |
|---|---|
| Model Number | APBMW-S8-4 |
| Component | Woofer |
| Power Handling (Continuous) | 150W RMS |
| Power Handling (Peak) | 300W |
| Impedance | 4 Ohms |
| Frequency Response | 35 ÷ 500 Hz |
| Item Weight | 3 pounds (1.36 kg) |
| Product Dimensions (L x W x H) | 9.41 x 9.41 x 7.52 inches (23.9 x 23.9 x 19.1 cm) |
| Voice Coil Diameter | 38 mm |
| Magnet Type | Neodymium |
Image 4.1: Technical drawing illustrating the dimensions of the subwoofer.
5. Setup and Installation
The Audison AP BMW S8-4 subwoofer is designed for a direct replacement installation in BMW vehicles, specifically fitting into the factory under-seat enclosures. Professional installation is recommended to ensure optimal performance and avoid damage to the vehicle's electrical system.
5.1. Pre-Installation Checks
- Verify the subwoofer's impedance (4 Ohms for S8-4) is compatible with your amplifier's output.
- Ensure the vehicle's battery is disconnected before beginning installation.
- Confirm the factory under-seat enclosure is clean and free of debris.
5.2. Installation Steps
- Carefully remove the existing OEM speaker from the under-seat enclosure. Refer to your vehicle's service manual for specific removal procedures.
- Place the provided 5 mm polyurethane gaskets onto the subwoofer's mounting surface. These gaskets ensure a perfect seal and decouple the subwoofer from vibrations within the enclosure.
- Position the Audison AP BMW S8-4 subwoofer into the factory enclosure. The design allows for a minimal installation depth, ensuring a proper fit.
- Secure the subwoofer using the provided mounting screws. Do not overtighten.
- Connect the subwoofer wiring to your amplifier. Pay close attention to polarity (+/-) to ensure correct phase.
- Reconnect the vehicle's battery and proceed to system testing.
Image 5.1: Side profile of the subwoofer, highlighting its compact design for under-seat installation.
6. Operating
Once installed, proper tuning of your audio system is crucial for optimal subwoofer performance. The AP BMW S8-4 is designed to integrate seamlessly with your vehicle's acoustics.
6.1. Initial Power-Up and Testing
- After installation, turn on your car's audio system at a low volume.
- Listen for any unusual noises or distortion. If present, immediately turn off the system and re-check all connections.
- Gradually increase the volume and adjust the subwoofer level on your head unit or amplifier.
6.2. System Tuning
For the best audio experience, consider the following:
- Crossover Settings: Set the low-pass filter on your amplifier or head unit to prevent higher frequencies from reaching the subwoofer. A common starting point is around 80-100 Hz, but this may vary based on your full-range speakers.
- Phase Adjustment: Experiment with the phase setting (0° or 180°) on your amplifier or head unit to achieve the most cohesive bass response with your front speakers.
- Gain Setting: Adjust the amplifier gain to match the output voltage of your head unit. Avoid setting the gain too high, as this can lead to distortion and potential damage.
- Digital Sound Processor (DSP): If using a DSP (e.g., Audison AP 8.9 bit), utilize its capabilities for precise equalization, time alignment, and crossover adjustments to maximize the subwoofer's performance.
7. Maintenance
The Audison AP BMW S8-4 subwoofer requires minimal maintenance to ensure long-term performance.
- Cleaning: Periodically clean the subwoofer's grille and surrounding areas with a soft, dry cloth. Avoid using harsh chemicals or abrasive materials.
- Environmental Factors: Protect the subwoofer from excessive moisture, extreme temperatures, and direct sunlight, which can degrade materials over time.
- Inspection: Occasionally inspect the wiring connections to ensure they remain secure and free from corrosion.
8. Troubleshooting
If you encounter issues with your Audison AP BMW S8-4 subwoofer, refer to the following common troubleshooting steps:
8.1. No Sound from Subwoofer
- Check Connections: Ensure all power, ground, remote, and signal cables are securely connected to both the amplifier and the subwoofer.
- Amplifier Status: Verify that your amplifier is powered on (indicated by a power light) and not in protection mode.
- Head Unit Settings: Confirm that the subwoofer output is enabled and the volume is turned up on your head unit.
- Fuse Check: Inspect the amplifier's fuse and the main power fuse for the audio system. Replace if blown.
8.2. Distorted or Weak Bass
- Gain Setting: Adjust the amplifier gain. If set too high, it can cause distortion. If too low, it can result in weak bass.
- Crossover Settings: Incorrect crossover settings can lead to distortion or a lack of impact. Adjust the low-pass filter.
- Phase: Incorrect phase can cause cancellation with other speakers, leading to weak bass. Adjust the phase setting.
- Enclosure Integrity: Ensure the subwoofer is properly sealed within its enclosure. Air leaks can cause poor performance.
8.3. Intermittent Sound
- Loose Connections: Re-check all wiring for any loose or corroded connections.
- Signal Cable Interference: Ensure RCA cables are routed away from power cables to prevent noise.
If these steps do not resolve the issue, contact Audison customer support or a qualified car audio technician.
9. Warranty and Support
The Audison AP BMW S8-4 Subwoofer comes with a 1-Year Manufacturer Warranty. This warranty covers defects in materials and workmanship under normal use.
9.1. Warranty Claims
To make a warranty claim, please retain your proof of purchase and contact your authorized Audison dealer or Audison customer support. The warranty does not cover damage caused by improper installation, abuse, accident, neglect, or unauthorized modification.
9.2. Technical Support
For technical assistance, installation guidance, or further inquiries, please visit the official Audison website or contact their customer support department. Contact information can typically be found on the Audison website or in the warranty documentation included with your product.
