The 1994 Mercedes Benz Convertible, particularly the E320 Cabriolet (W124), represents a pinnacle of classic automotive engineering, blending open-top freedom with renowned Mercedes luxury and performance. For owners of these iconic vehicles, maintaining and enhancing their classic charm while integrating modern technology is a common passion. One area where many owners seek improvement is the original sound system. While functional in their time, the factory audio setups often fall short of contemporary expectations, especially for enthusiasts accustomed to modern audio fidelity and connectivity.
This guide addresses common questions and considerations for upgrading the stereo system in a 1994 Mercedes Benz Convertible, focusing on enhancing audio quality while respecting the vehicle’s original design and electrical systems. We’ll explore options for replacing the head unit and speakers, addressing compatibility concerns, and offering insights for a seamless and satisfying audio upgrade experience.
Understanding the Stock Audio System of a 1994 Mercedes Benz Convertible
To effectively upgrade your 1994 Mercedes Benz Convertible’s sound system, it’s crucial to understand the original components. Decoding the VIN often reveals valuable information about the factory-installed audio equipment. For models of this era, you might find components like:
- Becker Radio Head Units: Mercedes frequently used Becker radios, known for their integration and classic aesthetics. These could range from the Becker Mexico cassette players to more advanced models like the Becker Grand Prix TR or MB-Exquisit for the USA market.
- Active Bass Loudspeaker System: Some models were equipped with an active bass system, indicating a separate amplifier likely located in the trunk, powering dedicated woofers, often found in the doors.
- Speaker Configuration: Typically, the system includes speakers in the dash, doors, and potentially rear locations. Factory speaker sizes were often around 5″ in the dash and 5.25″ in the doors and rear.
The original poster of the forum mentioned a VIN decode revealing “Becker Radio Mexico cassette,” “radio MB-Exquisit – USA,” and “Active bass loudspeaker system,” which is typical for a 1994 E320 Cabriolet destined for the US market. The key takeaway is that these systems, while advanced for their time, often lack the features and sound quality of modern aftermarket options.
Addressing Common Upgrade Questions for a 1994 Mercedes Benz Convertible Stereo
Many owners of 1994 Mercedes Benz Convertibles considering a stereo upgrade have similar questions. Let’s address these systematically:
1. Aftermarket Head Unit and Wiring Harness Compatibility
Question: “Can I just use an aftermarket adapter harness with the Alpine head unit, and access the current speaker wiring and amp that way?”
Answer: Yes, generally, you can use an aftermarket adapter harness. For the W124 chassis, including the 1994 convertibles, wiring harnesses are available that bridge the gap between the Mercedes’ factory wiring and standard aftermarket head unit connectors (typically ISO connectors). These harnesses simplify installation by providing plug-and-play connectivity, eliminating the need to cut or splice factory wiring.
Using a harness allows you to tap into the existing speaker wiring. However, the complexity increases if your car has the active bass system. In such cases, the factory amplifier receives a pre-amplified signal from the head unit and then powers the door woofers. When installing a modern head unit, which also has its own amplifier, you need to consider how to integrate or bypass the factory amplifier.
Recommendation: For a straightforward upgrade, bypassing the factory amplifier is often recommended, especially if you plan to upgrade speakers and potentially add a more powerful aftermarket amplifier later. Harnesses are available that facilitate this bypass. If you intend to retain the factory amplifier initially, you’ll need a harness that correctly interfaces with the low-level input of the amplifier. Consult with a car audio specialist or the harness manufacturer to ensure compatibility.
2. Speaker Size and Fitment: Dash, Doors, and Rear
Question: “Assuming that’s the case, I could install new dash and rear seat speakers. I’ve read that some folks are putting 5.25″s in the dash with minor shaving – any specs available on depth, magnet width, etc that will fit in there? Additionally, how much depth and magnet width space is available back there? Anyone have any tips on speakers they’ve actually used in a Cab, and how they sounded?”
Answer:
- Dash Speakers: The factory dash speaker size is approximately 5″. While some owners have successfully installed 5.25″ speakers with minor modifications (shaving the speaker mounting points), it’s crucial to be cautious. Depth is a significant constraint in the dash. Look for shallow-mount 5.25″ speakers or stick with 5″ speakers to avoid fitment issues. Magnet width should also be considered, as space is limited. Precise depth and magnet width specifications vary slightly by model year and specific location, but generally, you have limited space.
- Door and Rear Speakers: The doors and rear locations typically accommodate 5.25″ speakers without modification. Depth is less of a concern in the doors compared to the dash, but still, it’s wise to check the mounting depth specifications of any speaker you consider. For the rear, similar 5.25″ speakers will fit.
- Speaker Recommendations: For a 1994 Mercedes Benz Convertible, component speakers are often a good upgrade choice. These separate the tweeter and woofer, allowing for better sound staging. Brands like Infinity, Alpine, JBL, and Focal offer component sets in 5″ and 5.25″ sizes that are popular for car audio upgrades. When selecting speakers, consider their sensitivity rating. Higher sensitivity speakers will produce more volume with the same amount of power, which is beneficial if you are initially running them off the head unit’s power.
Tip: Before purchasing speakers, measure the available mounting depth in your specific vehicle or consult online resources and forums dedicated to W124 Mercedes Benz audio upgrades. User reviews and recommendations from other convertible owners can be particularly helpful.
3. Retaining Factory Amp and Door Woofers
Question: “A guy at a local (fairly respected) audio shop said that in these cars, they’ll often leave the amp and woofers in the door, rather than running new wiring to those, since the speaker placement is kinda poor anyway, and the woofers will give some additional bass. Thoughts on this? Assuming the answer to 1 is yes, this would greatly simplify things. I can always add an amp and other speakers in there later on.”
Answer: The suggestion to retain the factory amplifier and door woofers is a mixed bag. While it simplifies the installation initially, it often compromises overall sound quality.
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Pros of Retaining Factory Amp/Woofers (Initially):
- Simpler installation: Less wiring is required.
- Cost savings (short term): No need to buy a new amplifier or door woofers immediately.
- Some bass reinforcement: Factory door woofers do provide some low-end frequency response.
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Cons of Retaining Factory Amp/Woofers (Long Term):
- Sound Quality Bottleneck: Factory amplifiers and woofers from the 1990s are not designed to deliver high-fidelity sound compared to modern aftermarket components. They may become the weakest link in your upgraded system.
- Potential Impedance Mismatch: Connecting a modern head unit to a vintage amplifier can sometimes lead to impedance mismatches, affecting sound quality and potentially causing damage.
- Limited Power Handling: Factory woofers may not handle the increased power output from a modern head unit or a future aftermarket amplifier, leading to distortion or speaker damage.
- Speaker Placement: While door speaker placement in the W124 might not be ideal by today’s standards, modern aftermarket woofers and component sets are designed to perform well even in less-than-perfect locations.
Recommendation: For a significant audio upgrade, replacing the factory amplifier and door woofers is highly recommended in the long run. However, if you are on a budget or prefer a phased approach, you could initially retain the factory amp and woofers while upgrading the head unit and dash/rear speakers. This will provide some improvement. However, for the best sound quality, plan to replace the amplifier and door woofers (or install new component woofers in the doors) as the next step. Running new speaker wire to the doors for better quality aftermarket woofers will yield a much more satisfying bass response.
4. Functionality: Antenna, Amp Switching, Speed Switch
Question: “Again, assuming the answer to 1 is yes, will I lose any functionality, such as antenna up and down, amp switching, etc? And what’s up with that speed switch business? I’m assuming the new head unit won’t accommodate that, which is not necessarily a bad thing.”
Answer:
- Antenna Up/Down: Yes, typically, aftermarket wiring harnesses will include a wire to trigger the factory power antenna to go up and down when the radio is turned on and off. Ensure your chosen harness specifically supports this function for Mercedes Benz models with power antennas.
- Amp Switching: If you bypass the factory amplifier, amp switching becomes irrelevant. If you retain it (against the general recommendation for optimal sound quality), the harness should handle the remote turn-on signal to the factory amplifier. Again, verify this with the harness specifications.
- Speed Switch (Volume Adjustment): Some older Mercedes models had a speed-sensitive volume control, where the radio volume would automatically increase as the car speed increased to compensate for road noise. Modern aftermarket head units generally do not support this specific factory feature. However, many modern head units have their own automatic volume adjustment features based on ambient noise levels or user-adjustable settings, which can be a suitable, if not identical, replacement. Losing the factory speed-sensitive volume is generally not considered a significant loss in functionality, especially given the improvements in other audio aspects from a modern head unit.
5. Head Unit Removal in a 1994 Mercedes Benz Convertible (W124)
Question: “I checked out the W124 stereo article at http://www.peachparts.com/Wikka/W124Stereo. My understanding is that article is for earlier models… specifically, how does the head unit removal process differ from that article? Is it still necessary to yank the center shift console bits?”
Answer: The head unit removal process for a 1994 Mercedes Benz Convertible (W124) is generally similar to other W124 models of that era, but there can be minor variations. The PeachParts article you linked is a good general guide.
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Center Console Removal: Yes, in most cases, you will need to remove some portions of the center console trim to access the head unit mounting points. This typically involves:
- Removing the shift knob.
- Carefully prying up and removing the wood trim surrounding the gear selector.
- Potentially removing the ashtray and surrounding trim pieces.
- Unscrewing and removing side trim panels of the center console in some cases.
The exact steps can vary slightly depending on the specific year and trim level, but accessing the head unit usually requires partial disassembly of the center console area.
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Head Unit Release: Mercedes often used special release tools (radio removal keys) to extract the head unit. These keys are inserted into slots on either side of the radio faceplate, which release spring clips allowing you to pull the unit out. Aftermarket radio removal keys for Mercedes are readily available and inexpensive.
Tip: Before starting the removal process, consult a W124-specific repair manual or online video tutorials that demonstrate head unit removal for your model year. Work carefully and patiently with trim pieces to avoid damage. Plastic trim tools are highly recommended for prying and removing trim without scratching or breaking it.
Conclusion: Modernizing the Audio in Your Classic 1994 Mercedes Benz Convertible
Upgrading the stereo in a 1994 Mercedes Benz Convertible is a rewarding project that can significantly enhance your driving enjoyment. By understanding the original system, addressing compatibility questions, and planning your upgrade in stages (head unit and speakers first, amplifier and subwoofers later), you can achieve a modern sound experience while respecting the classic character of your vehicle.
For the best results, consider consulting with car audio professionals, especially if you are unsure about wiring or more complex aspects of the installation. With careful planning and the right components, you can bring the audio system of your 1994 Mercedes Benz Convertible into the 21st century, making every drive a pleasure for both the eyes and the ears.
