1. Introduzione
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. Ciò chì hè in a scatula
Disimballate cù cura u cuntenutu è assicuratevi chì tutti l'articuli sianu presenti:
- Audison AP BMW S8-4 Subwoofer(s)
- Two (2) 5 mm polyurethane gaskets
- Crossover (if applicable to your system configuration)
- Viti di muntatura
- Manuale d'uso (stu documentu)
- infurmazione di garanzia

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.
- Impedenza 4 Ohm: 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. Specificazioni
| Specificazione | Valore |
|---|---|
| Numero di mudellu | APBMW-S8-4 |
| Cumpunente | Woofer |
| Trattamentu di putenza (Cuntinuu) | 150W RMS |
| Gestione di a putenza (piccu) | 300 W |
| Impedenza | 4 Ohms |
| Risposta di Frequency | 35 ÷ 500 Hz |
| Pesu di l'articulu | 3 liri (1.36 kg) |
| Dimensioni di u produttu (L x W x H) | 9.41 x 9.41 x 7.52 inch (23.9 x 23.9 x 19.1 cm) |
| Diametru di a bobina di voce | 38 mm |
| Tipu di magnetu | Neodimiu |

Image 4.1: Technical drawing illustrating the dimensions of the subwoofer.
5. Setup è Installazione
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. Cuntrolli Pre-Installazione
- Verify the subwoofer's impedance (4 Ohms for S8-4) is compatible with your ampl'output di liificatore.
- Assicuratevi chì a batteria di u veiculu sia scollegata prima di inizià l'installazione.
- Confirm the factory under-seat enclosure is clean and free of debris.
5.2. Passi di stallazione
- 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.

Imagine 5.1: Pro lateralefile of the subwoofer, highlighting its compact design for under-seat installation.
6. Uperativu
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 amppiù vivu.
6.2. Ottimizazione di u sistema
Per a megliu sperienza audio, cunsiderate i seguenti:
- Impostazioni di crossover: 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.
- Ajuste di fase: 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.
- Impostazione di guadagnu: Aghjustate u 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.
- Processore di sonu digitale (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. Mantenimentu
The Audison AP BMW S8-4 subwoofer requires minimal maintenance to ensure long-term performance.
- Pulizia: Periodically clean the subwoofer's grille and surrounding areas with a soft, dry cloth. Avoid using harsh chemicals or abrasive materials.
- Fattori ambientali: Protect the subwoofer from excessive moisture, extreme temperatures, and direct sunlight, which can degrade materials over time.
- Ispezione: Verificate di tantu in tantu i cunnessione di i fili elettrici per assicurassi ch'elli sianu sicuri è senza corrosione.
8. Risoluzione di prublemi
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
- Verificate e cunnessione: Ensure all power, ground, remote, and signal cables are securely connected to both the amplifier è u subwoofer.
- Amplifier Status: Verificate chì u vostru 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.
- Verificazione di fusible: Inspecciona u amplifier's fuse and the main power fuse for the audio system. Replace if blown.
8.2. Distorted or Weak Bass
- Impostazione di guadagnu: Aghjustate u amplifier gain. If set too high, it can cause distortion. If too low, it can result in weak bass.
- Impostazioni di crossover: Incorrect crossover settings can lead to distortion or a lack of impact. Adjust the low-pass filter.
- Fase: Incorrect phase can cause cancellation with other speakers, leading to weak bass. Adjust the phase setting.
- Integrità di u recintu: Ensure the subwoofer is properly sealed within its enclosure. Air leaks can cause poor performance.
8.3. Intermittent Sound
- Cunnessioni loose: 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. Garanzia è Support
The Audison AP BMW S8-4 Subwoofer comes with a Garanzia di u fabricatore di 1 anni. Questa guaranzia copre i difetti in i materiali è a manuvra in usu normale.
9.1. Reclamazioni di Garanzia
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. Support tecnicu
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.





