Land Rover Discovery Shenxing: Using “invisible art to reshape low frequencies, in-depth analysis of the 0.8-inch spare tire bass system

In the upgrade scheme of car audio, using the trunk spare tire space to customize the exclusive bass cabinet is a very intelligent and efficient solution to use space. The key to the success of this modification method lies in whether it can achieve scientific matching and collaborative optimization among woofer unit, driver amplifier and cabinet design. Only precise matching can stimulate the majestic energy, deep dive and precise transient that low frequency should have, rather than just increasing the volume. Below, we will deeply analyze the construction philosophy and implementation details of this “spare tire bass system” through an actual modification case of a Land Rover Discovery Shenxing.

The core idea of this solution is to significantly improve the overall sound quality by installing professional equipment on the basis of retaining all speaker units of the original car, especially to make up for the low-frequency performance that the original system generally lacks. We have matched it with a set of cost-effective and outstanding combinations: First, add a high-performance DSP power amplifier to drive the original speakers of the whole car. This device is not only a power amplifier, but also the “brain” and “mixer” of the system. It can accurately digitally process the audio signal, correct the phase and frequency response problems caused by the complex acoustic environment in the car, and greatly improve the clarity, image and layering of the sound.

What’s more ingenious is that this DSP power amplifier has two low-level signal outputs (RCA outputs) specially designed for subwoofer. We will use this “pure” bass signal optimized by DSP and transmit it to the subsequent independent bass amplifier. The advantage of this is that the bass signal has undergone fine frequency division (frequency division), balance adjustment and phase alignment processing at the source, which ensures that the final output bass can be seamlessly connected with the middle and high frequency bands, and the sound is clean and flexible, and there will never be procrastination, turbidity or disconnection from the main body of music.

In terms of woofer unit, we chose an 8-inch woofer from the German brand Zero. This size not only ensures sufficient low-frequency sense of volume and dive depth, but also has excellent response speed and control, which is very suitable for the pursuit of quality in limited space. What drives it is a two-channel power amplifier also from Zero Point brand, which provides abundant, stable and fully controlled power support for this woofer unit, ensuring that its potential is completely released. The following is a record of the complete process from customizing the box to system installation.

Precision customization and installation of exclusive bass cabinet for spare tire space

All successful customization begins with accurate measurement and design. First, we collected three-dimensional data of the spare tire slot of the trunk of Land Rover Discovery Shenxing, and then designed the optimal internal volume and structure of the box according to the speaker parameters (such as equivalent volume, resonant frequency, etc.) of the selected 0.8-inch bass unit through professional acoustic software simulation calculation. The outer contour of the finished box body is millimeter-level consistent with the spare tire groove space, truly achieving a “perfect fit”. It is particularly worth mentioning that this box is not a simple closed design, but a carefully designed inverted hole (air outlet hole) with a specific size and structure. This inverted design can use the sound waves inside and behind the cabinet to adjust the phase through the inverted hole and then radiate forward, which is superimposed with the sound waves in front of the speaker, thereby effectively improving the low-frequency efficiency and enhancing the low-frequency sense of volume and dive depth under the same unit and power, and making the bass sound more elastic, relaxed and natural. Of course, this design is indeed much more complicated in calculation and manufacturing process than a simple closed box.

The effect of installing the box to the spare tire position is perfect. The bass unit is installed upward, and the box body is completely sunk into the spare tire groove, and its top surface is flush with the bottom plate of the carriage. Finally, the trunk cover of the original car was covered, and everything was restored as before. There was no trace of modification at all. The “invisible installation” was truly realized, and the complete storage space and aesthetics of the trunk were 100% retained.

The installation of electronic equipment also pays attention to concealment and regularity. The DSP power amplifier that drives the whole car horn and the zero-point two-channel power amplifier that specially drives the bass of the spare tire are fixed side by side in a safe corner. It can be clearly seen from the picture that next to it is the external power amplifier that comes with the original car. All newly added equipment coexists harmoniously with the original vehicle system, and the line connections are standardized and neat, showing professional installation standards.