Acoustic reconstruction of the German cockpit: the art and science of in-depth modification of the Audi A 4 three-way system

In the professional field of car audio modification, there is a wise saying widely circulated by both senior practitioners and enthusiasts outside the industry: “Three points of equipment, seven points of modification”. This concise summary accurately reveals the unique attributes of car audio products-they are essentially “semi-finished products”. The performance of audio equipment itself is only the foundation, and the final sound effect depends to a greater extent on complex and diversified modification work. This project not only involves rigorous acoustic design and fine installation technology, but also needs to deal with the ever-changing internal structure of different models. Its high difficulty comprehensively tests the technical experience, aesthetic judgment and even deep understanding of the scientific collocation of the entire system of the modification team. It is this characteristic that makes the value of professional modification irreplaceable. The modification scheme to be introduced below is not an armchair strategist idea, but a mature system that has been verified by repeated practice of many different models. It has achieved an excellent balance between sound quality and modification investment, and has a very high cost performance. This scheme, known as the “signature package”, has a good reputation that is by no means groundless, but is accumulated by the real listening experience and word-of-mouth of satisfied car owners. It is a veritable cost-effective choice.

 

The Audi A 4 owners who came to upgrade this time came here through the word-of-mouth recommendation of their changed friends, and chose this highly acclaimed modification package with a clear goal. Among the three German luxury brands, Mercedes-Benz, BMW and Audi (BBA), the sound performance of Audi’s original audio system is usually considered to be quite standard among models of the same class. However, in the new Audi car series, there is a common technical problem in its original car playback host: an inherent and extremely low-level circuit noise floor will be generated inside the system. This kind of noise floor is an inherent characteristic at the hardware level. When the audio signal is not amplified by an external high-power amplifier and only the original car system directly drives the speaker, it is basically undetectable to the human ear. However, after the subsequent installation of high-gain power amplifiers and processors, if the signal extraction, grounding processing or system debugging links are not operated properly, this noise floor may be amplified and become audible. What needs to be clear is that this noise floor originates from the host itself, and professional modification and debugging can control it at a very low level, so that it does not affect the purity of the main music signal and the perfect performance of the overall sound quality. Next, let’s take a look at the operation process and process details of this Audi A 4 audio upgrade through detailed picture records.

 

The standard “signature package” is the basic configuration, which does not include a subwoofer system or an eight-channel DSP processor. Instead, it comes standard with a six-channel system, which is designed to provide core high-quality sound improvement. Subwoofer and higher-level audio processors (such as eight-channel DSP) are usually used as late options for car owners according to their personal preferences and budget. The picture below shows a group photo of the “family photo” of the main equipment used in this modification.

The core step of sound field construction-A-pillar positioning and inverted formwork construction for the treble and midrange units of the three-way system. The technician is accurately measuring and fixing the position and angle of the unit according to the acoustic principle and the optimal listening point of the driver’s seat.

The overall rendering of the A-pillar three-way inverted mold modification is completed. The shape is smooth and natural, and the covering technology is exquisite, which perfectly blends with the original car interior style while ensuring the best radiation direction of sound.

 

The installation of the woofer unit in the door is the basic link that affects the overall sound quality. The first is to customize a high-density waterproof wooden gasket for the horn, and its size is precisely made in strict accordance with the structure of the original door panel horn position and the installation requirements of the horn. The quality of the installation process is directly related to the final presentation of the sound effect, and the installation of the middle and bass unit is particularly important. It profoundly affects the clarity and elasticity of the middle and low frequency bands, the thickness of the human voice and the solidity of the musical instrument performance, which can be called the cornerstone of the system sound.

Customize the process of installing gaskets on the door sheet metal to ensure stability and sealing.

The renderings after the installation of the mid-woofer unit are completed. The terminal blocks are protected in place and the installation is firm.

Special note: The golden yellow sound insulation and shock-proof material visible on the inside of the door was previously completed by the owner in other stores. The basic content of this “signature package” does not include the sound insulation project of the whole vehicle, and car owners can choose according to their own needs.

In order to further improve the quality of signal transmission, the owner additionally opted for a high-quality speaker cable from the British Van den Hul brand.

All terminal blocks of power and signal lines are made of professional-grade “Acura” brand consumables to ensure firm connection, minimize resistance, and ensure the safety and stability of long-term use.

The safety seat that independently supplies power to the entire sound system is installed for real shots, which is the core component to ensure the safety of the circuit.

 

Two power amplifiers and DSP audio processor are centrally installed on the side wall or baffle of the trunk. First, it is necessary to customize a high-strength fixed back plate (wooden board or other material) according to the installation space, and then install all equipment on this back plate in an orderly manner to achieve a clean, stable and easy-to-maintain layout.

As a later option, the owner installed a German Ground Zero 8-inch subwoofer and tailored a special box with acoustic calculations for it.

In addition, the owner also chose to install professional sound insulation materials for the hood to reduce the transmission of engine noise to the cabin and improve the overall driving quietness.