BMW 325 Li audio upgrade: Japan’s Biwei AM series three-way is equipped with an independent door mid-range cabinet, reshaping the mid-range acoustic characteristics

In the professional field of car audio modification, top audio equipment itself is often regarded as a “semi-finished product”. The logic behind this is that the more sophisticated the cutting-edge equipment, the higher its requirements for installation environment, debugging accuracy and system integration ability. Like a valuable Stradivarius violin, it can only shine with all its brilliance in the hands of top performers. Therefore, when customers are pursuing the ultimate sound effect, their vision has already gone beyond the simple selection of brand and model, and instead put the same or even higher weight into the crucial modification technology and engineering strength behind supporting this system. In addition to the recognition of exquisite craftsmanship, there is also a palace-level brand from Japan, which continues to attract real high-end audio enthusiasts with its persistent pursuit of sound purity and unique craftsmanship aesthetics-that is, Japan’s Bewith.

BMW 325 Li audio system in-depth customization solution configuration list:

1. Front soundfield core: Japan’s Biwei Am series three-way speaker set sets the precise and noble tone of the entire car’s sound.

2. Center and surround system: Thai QC brand 3-inch full-range unit, used to supplement the center channel and rear surround, creating an immersive surround feeling.

3. System-wide brain: Japan’s Biwei DSP-10-channel audio processor/power amplifier all-in-one machine is responsible for the precise reconstruction, frequency division management and power drive of the audio signal of the entire vehicle.

4. Ultra-low frequency cornerstone: Germany’s Ground Zero eight-inch subwoofer unit is equipped with an original factory-prefabricated optimized cabinet to ensure dive and strength.

5. Bass exclusive driver: Music System AU 500.1 D single-channel high-power amplifier provides abundant and pure energy for subwoofer.

6. Basic engineering and context: The whole door panel is made of Dishen sound insulation material for vibration suppression and sealing treatment; The full set of wires is Belden professional audio cable to ensure lossless signal transmission.

 

Next, we will share the core process details of this in-depth modification through detailed pictures and texts. Everything starts with laying a solid foundation-first complete the multi-layer sound insulation and vibration prevention project of the four doors to create a solid and quiet “audio box” for subsequent speaker installation.

 

In order to achieve more accurate and open front sound field positioning, we have carefully adjusted and fixed the angle of the installation position of the tweeter. Every slight angular deviation directly affects the condensation and height of the final sound image.

For midrange units, we didn’t settle for simple door panel installation. Instead, an independent acoustic cabinet is tailored for it. This measure can effectively eliminate the sound staining caused by the resonance of the door cavity, greatly improve the density and image-forming power of the intermediate frequency vocals and musical instruments, and make the sound stronger and cleaner, thus making the positioning stability of the entire front sound field reach a new height.

All wooden parts of the cabin are deeply waterproof, moisture-proof and anti-corrosion coatings to cope with the complex climate environment in the cabin and ensure its long-term stability.

Inside the cabinet, we attach appropriate amounts of sound-absorbing and tuning materials based on acoustic calculations to optimize the air flow in the cabinet, absorb harmful standing waves, and make midrange playback smoother and more natural.

The midrange box is finally perfectly integrated with the door panel structure, and the craftsmanship is rigorous, which reserves a perfect interface for subsequent restoration.

The midwoofer unit, located under the front seats, is equally critical to its installation. We have made an exclusive mounting base and sealing gasket for it to ensure that it is tightly coupled with the body sheet metal and effectively excites low frequencies.

The single-channel power amplifier that drives the subwoofer is cleverly hidden and installed in the decorative panel on the left side of the trunk, which not only saves space, but also maintains the overall beauty and tidiness.

As the core of the system, the Biwei ten-channel DSP power amplifier is placed in an exclusive position on the side of the spare tire slot in the trunk. The layout is reasonable and is easy to connect and debug.

In order to ensure the electricity safety and stability of the entire high-power audio system, we have installed a high-performance safety seat at the power input end, which is an indispensable safety link for professional modification.

Germany’s 0.8-inch subwoofer cabinet is placed in the trunk, and its high-quality original cabinet can ensure that the woofer unit works in the best condition, providing a deep and flexible low-frequency supplement.

When all the top hardware is installed to the highest standard, the whole system engineering ushered in the final and most decisive link-professional audio debugging. Only through precise measurement and delicate manual adjustment can all “semi-finished” equipment be integrated into a harmonious whole, awaken its soul, and finally present the sound of nature that car owners expect.