Upgrading The W205 Burmester Audio

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This blog details upgrades I made to the Burmester audio system in my 2016 C300. I knew right away that, while the stock system didn’t sound hopeless, I wasn’t going to be satisfied with it. The bass was too loose and sloppy, and the mids were too bright and harsh. Frankly it didn’t sound “premium” enough for my tastes. I want clean, powerful, accurate reproduction with distinctive and punchy mid-bass, a solid “thump” for the kick drum sound, and mids/highs that are clear without being brassy or harsh. I also like a wide sound stage, where the stock system seems to sound very directional and and overly focused to the front door speakers.

When I’m evaluating an OEM car audio system I trust my ears. I don’t care whose name is on the equipment necessarily.  I’ve been a musician professionally and for fun for thirty years, and while my tastes lean toward audiophile, my budget generally does not. But I am a hardcore audio geek with experience performing and mixing sound in the studio and live venue settings.

When I first get into a new car, I’ll spend a couple of weeks just listening. I’ll play source material I’m really familiar with, try the various settings, see if different sources sound better than others, and really try to pin down any deficiencies.  I’m never doing a “gut job” and replacing otherwise good gear. It’s more a surgical approach based on where I perceive any shortcomings.

I’ve learned that there are two potential areas of deficiency in any car audio system. Physical deficiencies, such as a lack of a full compliment of speakers due to space or design limitations, a lack of sufficient power, over-reliance on inexpensive components with inherent flaws, and a lack of sufficient user control over equalization.

Tuning deficiencies almost always result from a manufacturer’s attempt to compensate for physical deficiencies by equalization, delay, and other processing. Tuning deficiencies are “baked” into the system and cannot be modified by the user. Sometimes manufacturers do a convincing job. (Bose, for example, is notorious for coaxing somewhat decent audio from inexpensive hardware using equalization and post processing and then charging a fortune for it.)

W205 Burmester Deficiencies: No True Woofers, Too Many Midrange Speakers, Inadequate EQ controls.

Most of the deficiencies in the W205 Burmester result from a lack of a full-range array of speakers, inexpensive components used for the speakers it does have, and tuning deficiencies created by the equalization scheme necessary to compensate. In short, the Burmester lacks any conventional woofers necessary to accurately reproduce the mid-bass range, which is what woofers do best. Additionally, the speakers that do exist are flimsy and cheap. (There are no “Burmester” components in the W205 Burmester system. Burmester was responsible for designing and tuning using  existing off-the-shelf parts from other manufacturers, a common practice in branded premium car audio systems.)

The W205 Burmester is essentially a sub/sat design, much like those all-in-one, “home theater in a box packages” that rely on a bass module for the lows and a bunch of little satellite speakers for everything else. Inexpensive and space efficient but not ideal.

Here’s the speaker array in the W205 Burmester, clockwise from the driver’s side front door.

• 4” midrange & 1” tweeter left front door passive crossover*
• 6” subwoofer left front footwell
• 4” midrange center dash
• 6” subwoofer right passenger footwell
• 4” midrange & 1” tweeter right front door passive
• 4” midrange & 1” tweeter right rear door passive
• 4” midrange left parcel shelf (left surround)
• 4” midrange right parcel shelf (right surround)
• 4” midrange and 1” tweeter left rear door passive

*A “crossover” is a device that routes signal based on a frequency range to the speaker most optimal to play that range. So in a two way system, only lower frequencies would go to the woofer, and only highs to the tweeter. The cut off points are determined by the crossover. A “passive” two way or three way component speaker system has a physical crossover with fixed settings. An active multi-speaker system has separate channels wired directly from each speaker in the set back to the amp and the settings can be manipulated electronically. Active crossovers are preferred for their tuning flexibility.

One  look at the speaker array in the Burmester system and it becomes obvious that the W205 got a lot of 4” mid range drivers, seven in total, and four tweeters. So plenty of mids and highs.If I had to boil down the main problem with the Burmester, it’s the glaring lack of any proper woofers. Typically you’d use the nice cavities in the lower doors for a 6″ woofer, ideally suited for bass and mid-bass. For whatever reason, Mercedes decided to use that real estate for other purposes, namely an awkwardly placed and superfluous cup holder and a map pocket. It may have solved the “where do I put my second beverage?” problem but it ham-strung the audio designers. The major flaw in the C Class Burmester is that Mercedes got too clever by half when they relied entirely on Frontbass for the mid-bass down to the lows. It’s just not a great solution.

To cover the mid bass gap that exists physically between the 6 inch “subs” in the footwells and the 4” mids that are everywhere else, the Burmester relies on a “baked in” equalization and surround processing scheme. It forces the mids to play a little lower than they’d like, and it forces the “subs” to play way both higher and lower than ideal. But there’s only so much digital hocus pocus you can do to compensate for an incomplete speaker array and a flawed bass scheme.

Which is why, when you’re listening to the Burmester and you’d like punchier, more well defined bass, adding more bass via the COMAND “Equalizer” makes the sound become loose and boomy. If you increase volume to get more grunt in the bass, the mid range becomes intolerably bright and harsh: A tuning deficiency necessitated by a physical deficency.

Here’s what we saved/replaced/added 

• 4” midrange & 1” tweeter front doors (FOCAL KRS100)
• 6” subwoofer left front footwell
• 4” midrange center dash
• 6” subwoofer right passenger footwell
• 4” midrange & 1” tweeter rear doors
• 4” midrange left parcel shelf (left surround)
• 4” midrange right parcel shelf (right surround)
• Dual 8″ Subwoofer (Trunk)

So not a total gut job as far as the speakers. Most of the work involved gaining control over the factory equalization.

Where’s the Burmester Stuff?

Not surprisingly, there is no actual Burmester sourced hardware in the W205. If I had to guess, based on their form factor, tri-lobe mounts and sound, the speakers are harman/kardon. The amp is not Burmester either. Burmester’s contribution appears to have been limited to design and tuning, and most importantly, lending its name to Mercedes to stamp on the speaker grilles.

Here’s a side-by-side of the “Burmester” 4″ door speaker and 1″ silk dome tweeter with a common harman/kardon 4″ woofer and 1″ silk dome speaker, found extensively in Mercedes and BMW systems dating back ten years.

From Top Left, Clockwise.

Rear view of Harman Kardon Tweeter (left) and Burmester Tweeter (right)

Front view of Harman Kardon Tweeter (left) and Burmester Tweeter (right)

Rear view of Harman Kardon 4″ woofer (left) and Burmester 4″ woofer (right)

Front view of Harman Kardon 4″ woofer (left) and Burmester 4″ woofer (right)

It’s common for manufacturers to use high efficiency, wispy little nothings for speakers in their systems. They’re inexpensive, and very easy to drive without a lot of amp power. That allows the amps to be smaller, be low heat producers and cost less.

I point this stuff out not to bum anyone out on their Burmester system. But if you were feeling bad about messing around with Dieter Burmester’s masterpiece, don’t.

The Cure: Use The Footwell Subs As Conventional Woofers, Add A Trunk Sub For The Lows, Strip Out The Factory EQ And Start Over.

Once I knew what I was working with, I was able to design the upgrade.  My goal is always greater fidelity and accuracy, not necessarily more power. I avoid adding big sub-woofer boxes (or subs at all if I can), and I’m not interested in huge impressive looking amplifiers in special custom enclosures.  I also avoid making any modifications to the factory system that would ruin the integration and controls. Any changes I make happen very late in the signal chain, right before the connections to the speakers. My systems are pure stealth and use the factory speaker locations and sizes, and the factory grilles.

To re-mediate the lack of “proper” woofers, it was necessary to re-purpose the dual 6” Frontbass subwoofers to become conventional mid bass woofers by changing their crossover points to cut out a chunk of the low bass signal to them. (This is all done by software…no physical changes are being made to the Frontbass subs themselves.)

Making the subs into  woofers allowed me to create a proper 3 Way component system for the front sound stage, consisting of the 6” woofers in the footwells, 4” midranges in the doors and 1” tweeters in the sail panels. However, the low bass signal being redirected away from the front subs had to be reintroduced, and that necessitated a subwoofer box in the trunk. That allowed me to tune the fronts to play a nice full-range sound without the bass getting loose or sloppy, but still have sufficient low end reproduction.

For this install I chose to replace the front door 4” and tweeters with a set of Focal KRS100 components which I already had on hand. The other speakers in the car were left stock.

Edit: Since originally writing this article I’ve acquired an ’18 BMW 430i Coupe. The Harman Kardon system in that car would break your heart. They put two 8″ shallow mount subs under the front seats that hit like crazy, and IDrive includes an excellent built in seven band equalizer that makes tuning a breeze. It also has CarPlay and can play Hi Res 24bit audio in FLAC and ALAC from a USB stick. I’m pretty much in audio heaven with the 430. Still I felt like I had to do something to it, so we replaced the front and rear 4″ two-ways with Morel 402 Hybrids. I prefer them to the Focals. The woofers can actually play low and the mids and highs are warmer, which would be a big help in the 205. Cost is comparable. 

With the speaker array sorted out, my attention next was focused on removing  the factory equalization and tuning, so I could start from scratch with a clean, flat stereo signal from COMAND. There is unfortunately no way around this, and it’s expensive to do it right. You could replace every speaker in the car with high end alternatives and you’d still be stuck with the many of the same issues if you didn’t also address the factory EQ. If you had to pick the most efficient way to improve the system, start with a digital signal processor rather than speaker replacement.

For processing duties I’m using the  Audison Prima 8.9 DSP Amp already on hand, which combines a robust digital signal processor and an integrated 8 channel amplifier, with an un-powered 9^th channel output for a sub amp and speaker. It’s a compact unit, about the size of a hard cover book. While the power output is relatively tame at 35 watts per channel x 8 into 4 ohms. it’s an honest 35 and proved more than enough for the W205. (In fact, it was more than enough for my 2010 S550, with a much larger cabin.)

The Prima is tuned by temporarily connecting a USB cable from it to a Windows laptop and running the Bit tuning software application. Each channel can be tuned individually for level, EQ, time correction, and crossover. Here’s a sample tuning screen for a single channel. On the upper left, clicking on a speaker in the car diagram brings up EQ, Crossover filter and Time Correction (delay) for that speaker. Here, the left front door midrange is being tuned.

Don’t get turned off if none of this stuff makes any sense to you. I’ll include the Prima tuning file for this W205 installation here. You can simply download it, load it to the Prima and save, and its done. If you want to play around with it as a starting point, just save your changes with a new file name.

To handle sub-woofer duty I used a 300 watt JL mono amplifier (also on hand), and a small JL sub box for the trunk. My preference would be to avoid a box entirely. They look aftermarket and take up trunk space, but one was necessary for the 205. I was able to find a shallow depth JL box with two 8” subs that fit perfectly and snugly up against the back seat of the 205. (Quick disconnects make it possible to remove the sub to gain access to the folding rear seats.)

One extra component I didn’t anticipate needing was necessary to defeat the Burmester’s Vehicle Noise Compensation circuit, which is supposed to listen for road noise and bump up certain audio frequencies to mask the noise. VNC got all discombobulated once the Prima was installed and was just throwing out random bursts of low bass. The cure was to add a JL Fix 82 OEM integration module, which was able to strip out the VNC interference. We hunted endlessly for the presence of a cabin mic that might be used by VNC but had no success. If anyone does figure it out, let me know.

The equipment list then is as follows. Prices are estimates.

1. Audison Prima 8.9 DSP Amp OEM Integration Unit ($900)
2. Focal KRS100 K2 Power 4” OR Morel Hybrid 402 2-Way Component Speakers ($750)
3. JL Fix 82 Processor ($300)
4. JL Dual 8” Shallow Depth Ported Subwoofer ($400)
5. JL 300 Watt Mono Sub Amp ($300)

The Sub amp and box are optional here. While it’s nice to have the bass drum sound reinforced, simply tuning the existing front woofers is a huge help. If you were approaching this in stages, just the JL Fix 82 and Prima are the only “must-haves”

Morel Hybrid 402 as an alternative to the Focal KRS100

Installation included applying Hushmat sound dampening material on the interior panels of all four doors, plus the usual battery power kit, cables, ties, etc. I handled the Prima’s initial configuration and the tuning myself.Get a quote on installation from you nearest authorized Audison retailer/installer.

The signal-processing chain is as follows:

• Speaker Outputs from the 9 channel Burmester amplifier are fed to the Fix 82.

• The Fix 82 converts the powered speaker level signal back down to low voltage (line level). It digitizes the signal, removes the factory equalization, time correction and VNC and outputs flat 2 channel stereo via a single fiber optic Toslink cable to the Prima.

• The Prima’s DSP stage is where the tuning magic happens, with immense control over every aspect of the sound on an individual channel level. Equalization, crossover points, level, phasing, and time correction can all be customized using a Windows laptop and a USB connection. Tuning the Prima in my 205 took four hours, but if this process is entirely foreign to you, I’ve included the W205 specific tuning map file below. Your installer can simply load it into the Prima and you’re done.

• The Prima’s eight powered output channels are configured as follows:
  • Channel 1: Left front mid range and tweeter 35 watts
  • Channel 2: Right front mid range and tweeter 35 watts
  • Channels 3-4: (Bridged ) Left front subwoofer 70 watts
  • Channels 5-6: (Bridged) Right front subwoofer 70 watts
  • Channel 7: Right rear mid range and tweeter 35 watts
  • Channel 8: Left rear mid range and tweeter 35 watts

• The 9^th output channel is used to send signal to the outboard JL sub amp and box. The center channel and two rear deck surround speakers remain on the factory amp. The tuning blends these “orphaned” speakers into the mix.

Here’s everything, installed in the trunk.

And the sub box, which squeezed perfectly up against the rear seatback, leaving plenty of trunk space:

So there you have it. A system that now sounds as good as its speaker grilles look, all invisible and with no loss of COMAND control or functionality.

Installation:

Burmester_WiringDiag (1)

• Come off the high side of the factory amp, and using the Burmester wiring diagram identify the speaker wires by color code as follows:
  • Left front door
  • Left front sub
  • Right front sub
  • Right front door
  • Right rear door
  • Left rear door
• Cut those leads and run them to the input side of the Fix 82.
• Run the Fix 82 set up CD.
• Connect a Toslink fiber optic cable from the Fix 82 to the optical input on the Prima.
• Run leads back from the high (output) side of the Prima and connect them back to the car’s speaker wires.
• Run a cable from the subwoofer out of the Prima to your outboard sub amp and speaker.

Prima Configuration Wizard

• Set the physical configuration switch on the Prima to Zero.
• Connect a USB cable from the Prima to a Windows laptop and run the set up software.
• Skip the level set up and de-equalization as the JL Fix 82 has that handled.
• Here’s the speaker configuration. Note the boxes checked beside the front subs, denoting a bridged connection (two channels combined to double the power). Also note that each speaker set connected together by a passive cross over has a green bracket. To combine two speakers, click each one. A white bracket will appear joining them. Click the X in the middle of the bracket to tie them together, and the bracket will turn green.

Here’s the output configuration channel assignments. Note that two channels are assigned to each front sub.

Be sure to select Optical for the input.

Tuning

The first time you turn this system on you’re not going to like what you hear at all. With the factory EQ removed, the raw sound is pretty awful. All of those mid range speakers doing their thing. Luckily you have a monster digital signal processing suite at your finger tips and all of those speakers can be bent to your will.

Save this file to your laptop:

W205 Prima Tune

In the AP Bit program, select “Load” and browse to this file. Select Device>Finalize The Device to write the tune to your system. Feel free to poke around in the tuning app and see how changes to things like the filter and EQ affect the sound. Use the Solo feature (yellow light at the top of each channel’s level fader) to see how each individual speaker sounds in isolation and how it contributes to the overall mix.

Try soloing the front subs plus the subwoofer to tailor the bottom end. Do the same with the four doors to fine tune the mids and highs. If you get something you like, save it with a new file name. Use the car’s COMAND equalizer and surround functions to make fine adjustments. I have Treble on 6+, Midrange -8, Bass +2. My most common source are AAC files on an Iphone, both local and streaming, and Tidal.  Fine tune to whatever you listen to most often. Every source imparts its own characteristics. If you’re using Bluetooth Audio, pull the jog wheel down to bring up the bottom menu, select Options>Volume>Boost.

I use Front Surround, and have the Automatic Volume Control on. (Vehicle screen, pull down on the jog wheel to bring up the lower menu, go to Vehicle Settings and scroll down.

Burmester himself famously stated that the best system is the one you never need to touch, because everything sounds good on an accurate, balanced, neutral system. I agree!