Contact us
Close contact box
Connect ID #
426 236 246 3
Connect ID #
426 236 246 3
All finished with your chat session?

We’ll email you a transcript of this conversation for your records.

All of our representatives are
currently chatting with other customers.

Please enter your name.  
Please enter a valid email address. Why is this required?
Please enter your US phone number.  

For Tech Support, call 1-888-292-2575

Thank you, !
Our conversation will be emailed to
Chat Advisor Image

Your Advisor,

More about me
Please enter a question  
Don't wait on hold. We'll call you back when it's your turn to talk with the next available .
Please enter your name  
Please enter your phone number  

Please enter a message  

Calls may be recorded for training and quality control purposes.

We are located in Virginia USA.

Rick S's 2004 BMW 330i

Stereo upgrade using a JBL MS-8 processor

Heads up!

Welcome to this article from the Crutchfield archives. Have fun reading it, but be aware that the information may be outdated and links may be broken.
Rick in his car

Rick in his car

Items installed:

Upgrading the sound without changing the look

Would you believe the car pictured below had its sound system completely overhauled, yet kept its factory stereo? These days, you can add high-performance upgrades and get luxurious sound without having to tear your dash apart. Rick, one of our vice presidents, put this concept to the test by adding a JBL MS-8 system integration processor to his 2004 BMW 330i, then replacing his factory speakers and adding a JBL amp and an Infinity sub. The result is one happy VP. After hearing about it, I had to take a few minutes to talk to him about his new system.

BMW dash

The dash of Rick's BMW is unchanged after the audio upgrade

Even "premium" factory systems can stand improvement

Buck: Why did you decide to upgrade your A/V system?

Rick: I didn't want to touch the dash of my car. I like the look of it and I don't want anything messy hanging off it. So, nothing's changed as far as the factory radio is concerned — all the controls are exactly the same. What has changed is the sound — the experience of listening to music is new and exciting again.


Buck: Why did you decide to upgrade your A/V system?

Rick: My car came with a Harman Kardon premium system from the factory. It sounded okay, but not as good as I wanted.


Buck: Why did you choose these products?

Rick: What's in there now are higher-quality aftermarket products made by the same company. Harman International also owns JBL and Infinity, and the results are like night and day. I knew going into it that just adding the processor would improve my sound. But upgrading the other parts of the system at the same time made it sound really super.

MS-8 display

The MS-8 processor's display

Buck: Did the installation accomplish what you wanted?

Rick: Absolutely. The new Infinity Kappa component speakers sound brighter, and the stereo imaging is so much better than it used to be. The subwoofer and that powerful little amp add a complete bottom end to all my music that I just didn't have before. The MS-8 has this little display we used for the automatic calibration process. If I wanted, I could mount it on the dash and adjust the 31-band EQ manually as I listen.


Buck: How difficult was the installation of the processor?

Rick: It's not that hard to integrate. You plug the MS-8 into the end of the system, after the factory stereo, or in my case the factory amp.


Buck: How about the amp? Anything special?

Rick: It's small, so it's easy to find a place to install it. You should see my car. It's really slick. The amp's in there to power the sub. The MS-8 contains a smaller amplifier that takes care of and improves the sound of the other speakers.

Inside the trunk

Thanks to the compact designs of the amp and processor, and this neat installation, Rick still has plenty of room in his trunk for luggage.

A closer look at the products

It's clear that Rick is in love with the way his new audio system sounds. Below is a more in-depth run down of the products he's using.



The JBL MS-8 System Integration Digital Processor is one of the best ways to improve your sound quality dramatically, especially if you want to keep your factory stereo, or have a system with more than four speakers. The MS-8 automatically equalizes and time-corrects your audio so you'll hear the entire spectrum of your music's notes evenly, with no distorting peaks or echoes, exquisitely balanced and tuned for every seat in your car. The MS-8 can drive up to eight speakers with its built-in amp, and includes individual preamp output control, a 31-band graphic equalizer, and a wireless remote for fine-tuning while you cruise.

JBL MS-A5001 amplifier

JBL MS-A5001 amplifier

JBL's stylish 7" by 7" Class-D MS Series amps (Rick used the single-channel MS-A5001 amplifier) can tuck into virtually any hiding place that has adequate ventilation. A bright digital display shows the filter slopes, crossover points, and gain settings for each channel. These amps come with a set-up CD and have built-in indicator lights that help you set the input gain perfectly. They also feature preamp and speaker-level inputs so you can hook them up to almost any system.

Infinity component speakers

Infinity component speakers

The Kappa component speaker system features woofers with responsive woven glass-fiber cones that won't flex during a hard workout. The soft dome tweeters handle an impressively wide range of frequencies which help define the intricate details in your music. Rick's car used a set of 5-1/4" Kappa components in the front doors.

Infinity Kappa subwoofer

Infinity Kappa subwoofer

Each 10" Infinity Kappa subwoofer features the Selectable Smart Impedance design, which lets you build exactly the system you want, high-power or multi-sub, for the kick you like. The Sound Ordnance sealed enclosure focuses the subwoofer's output to create tight, well-defined bass.

the car

Rick's BMW 330i — a rolling concert hall

Most vehicles in the Customer Car Showroom are submitted by customers and fans, and edited by Crutchfield writing staff. You can find more of these articles on the Showroom main page.

  • TJ from NORWALK, CT

    Posted on 10/15/2019

    Is that a ZHP? It may be older but those are one of the slickest BMWs they have ever made. I just purchased an 03 330xi (5-speed) woth 60k mikes on it and I'm in the process of overhauling the system in it. I'm using JL Audio VXi (8 channel) amp/DSP. What I'm wondering is if I unplug the HK amp from the head unit , will I have any problems with any of the existing functionality? Note: I do have an aftermarket unit (XTrons) that was originally using an adapter to connect to the OEM wire harness but it also has RCA outputs, so I'd like to take advantage of that if possible. I just don't want to disconnect the HK amp and find out that other things were routed through it. Any info/guidance you can provide would be greatly appreciated! Thanks, TJ

    Commenter image

    Alexander H. from Crutchfield

    on 10/18/2019

    TJ, we're not seeing anything in our vehicle guide that would trip you up. The only thing that might be an issue is if that HK system utilizes load sensing, but if you're replacing speakers too, you might be working around that potential problem. That XTrons unit sounds like it might allow you to run some tests without totally uninstalling that factory amp -- probably a worthwhile endeavor. If you need any assistance with gear, give us a call. If you bought your gear from Crutchfield, you can call Tech Support for free help troubleshooting your system. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Check out our tech support page for details.
  • Commenter image

    Buck Pomerantz from Crutchfield

    Posted on 3/3/2016

    Philip, Most of the items mentioned in this article are discontinued, but Crutchfield carries similar, and more up-to-date digital signal processors and amplifiers that may suit you and work well in your car. I've forwarded your questions to Crutchfield's Sales Advisor Team, and a member will get in touch with you by email to offer suggestions and help you choose the right gear for you and your vehicle. For immediate help, you can contact them via phone or chat - just click on the phone icon at the very top of this page.

  • PHILIP LAWLER from west chester pa 1938

    Posted on 3/2/2016

    i would like a similar system.could you give me price range.I DRIVE A 2004 BMW 330CI THANK YOU FOR YOUR EXPECTED RESPONSE.

  • Commenter image

    Buck Pomerantz from Crutchfield

    Posted on 10/13/2015

    Gary, Sorry to say that most of the items mentioned in this older article are indeed discontinued. We'd like to leave the article up so everyone can see how this kind of upgrade looks and works. We will probably edit it, in the future, so we can point out the other digital signal processors we now have available.

  • Gary Hughes from Stockton CA

    Posted on 10/12/2015

    nothing was available except the 10" subwoofer and the bass bunker. Pretty useless info.