The owner of this 2015 5-Series BMW contacted the team at Extreme Audio in Mechanicsville to inquire about upgrading the factory stereo system. After talking with the client about what he liked about the sound system and what he wanted to improve, we inspected the 528i to confirm which audio system it came with. Armed with this information, we designed a high-power amplifier and subwoofer upgrade that would sound amazing. Since the client liked the plan and was confident in our abilities, he gave us the go-ahead to schedule an appointment to begin the project.
JL Audio System Amplifiers
We started the stereo upgrade on this 5-series BMW by removing the factory audio system amplifier from the left-hand corner of the trunk. Next, we added a custom-made interface harness to the cable that comes from the factory-installed radio. This harness extracts a full-range audio signal from the radio and allows us to feed this signal to the inputs on a JL Audio VX600/6i amplifier. This six-channel amp provides a healthy 75 watts of power from each channel and will drive the speakers in the front of the vehicle. Our integration technicians mounted the VX600/6i on the left side of the trunk and made a secondary bracket to secure a JL Audio XD600/1 600-watt monoblock amplifier on top of it. Once we had the system tuned, the factory trim panels went back in place, making the electronics completely invisible.
Musicar BMW Subwoofer System
An important part of this stereo upgrade was to add a premium subwoofer to the car. To make things simple, we ordered one of the OE-Look subwoofer enclosures from Musicar Northwest. This enclosure features thick fiberglass construction that is contoured to the shape of the trunk to provide as much internal air volume as possible for the given space. The face of the enclosure is finished in a gray carpet similar to the rest of the trunk interior. The shape of the enclosure and the position of the woofer make the system look as though it was a premium option from BMW. We installed a JL Audio 10W6v3-D4 10-inch subwoofer in the enclosure. This sub, combined with the 600-watt amplifier, will deliver low-frequency extension that no factory-installed stereo could ever dream of producing.
The Importance of Signal Processing for Great Sound
The JL Audio VXi amplifiers have a built-in digital signal processor that our technicians used to set the crossover points, output levels and signal delays for the midrange speakers and tweeters in the doors and the woofers under the front seat. They also configured the preamp output of the amp to drive the XD amp and the subwoofer on the right side of the trunk.
The settings in the digital signal processor allow us to compensate for the different distances between the listening position in the driver’s seat and the variations in speaker placement around the vehicle. We adjusted the output level of each speaker and applied a delay to the signal.
The next step was to apply equalization to each speaker in the car to adjust for reflections and resonances in the vehicle. As you can see from the photo of our audio signal analyzer, the result is a smooth and balanced frequency response with no dips or peaks at any frequency.
BMW 5-Series Stereo System Upgrade
Our team of technicians finished the installation and configuration process on this 5-Series BMW and we called the client to let him know his vehicle was ready to go. He got in the car for a listen as soon as he arrived at the store. The system now had the volume capability he wanted as well as an appropriate amount of bass to make the music he enjoys come to life. After a quick listening session, we showed him the work we had done in the trunk. He was thrilled that we were able to make the stereo sound so much better without the need for a big subwoofer enclosure that would take up cargo space.
If you’re interested in enhancing the performance of the audio system in your car or truck, we invite you to visit Extreme Audio in Midlothian or Mechanicsville and speak to a member of our team. You can also contact us using the e-mail form on our website.
So glad to come across this article. I’m a military servicemember and stationed in Memphis, TN and just purchased a 2019 BMW 540i last that’s in serious need of and audio upgrade from factory. Do you sell the custom-made interface harness to the cable that comes from the factory-installed radio and the amp mount. Did you have any problem with the ohm load as i hear the BMWs are unique in that area? Thanks again for a great read and giving me some hope that i might be able to solve my problem.
We definitely have access to the cables and some pre-done for BMW DSP amplifiers depending on how big of an upgrade you’re looking to do. If you’re looking to DIY the installs, I would talk to Jack at our Midlothian location. He can be reached at 804-302-4488 or jack@extremeaudio.org. If you’re looking to have a shop do the work, we have a good friend in Jackson, TN that you can work with. It’s called JC Audio, and we’ve known the owner Jeff there for a long time. They would do great work and could be reached at 731-660-2834