NEW: Visit my write up and walk-thru to create your own Dolby Digital 5.1 Surround, and 24 Bit Hi Res Stereo Audio DVDs for your S550

This blog chronicles my experiences with upgrading the performance of the Harman/Kardon Logic 7 audio system that came standard in 2007-2012 Mercedes Benz S Class & CL Class. While I’m dealing specifically with the S Class here, the system in the CL is similar, and generally all Logic 7 systems in Mercedes of the same era share most components. The Logic 7 suffers from the following shortcomings:

  • The midrange is over emphasized, resulting in a sound that is too bright, too thin and too brassy. Turning up the volume just exacerbates the problem.
  • There is inadequate bass response, despite the car having three subwoofers. Overall the sound is weak and thin, and not in character with the car itself.
  • There are insufficient tone controls in COMAND to compensate.

I’ve spent two years methodically chasing down the Harman Kardon’s shortcomings with an eye on getting high end sound, but also on the budget, trying to salvage anything I could, and making sure not to do anything that would devalue the car or interfere with the audio system’s integration.

I discovered that hidden behind a lousy factory EQ and a few notably terrible sounding speakers is a really spectacular sounding system, and the solution was a Prima 8.9 digital amp/signal processor and replacing the door speakers.

The blog begins with the oldest post, so scroll down if you want to follow the process and see the steps along the way. If you just want the good stuff, review the earliest post regarding the speaker upgrade, and the most recent post regarding installation of the Prima 8.9 OEM integration module/DSP amplifier.

Audison Dealer Locator: Audison US Dealer Locator 

The Whole Enchilada: Audison Prima 8.9 Completes The Premium Audio System

After two years of half measures and incremental improvement, last week I decided to go all-in for an aftermarket OEM integration unit, and I’m beyond satisfied with the results. OEM integration is a solution for cars like the 221 with complex and deeply integrated infotainment systems that do not play well with normal aftermarket gear. I chose the Audison Prima 8.9. It combines a digital signal processor with an integrated 8 channel power amp. An additional un powered 9th channel is available for a subwoofer and outboard amp. (Hence the “8.9” model designation. Really it’s an 8.1 channel amp.)

The Prima is a great fit for late model Mercedes like the 221 where owners want aftermarket sound but are reluctant to do a “gut job”. It gives you the extra power and sound shaping flexibility of aftermarket signal processors and amps in a compact unit that installs after the factory amp and before the factory speakers. It essentially intercepts the output from the factory amp, cleans it up, fixes the EQ, and sends it along to the factory speakers using the factory speaker wires. (You could of course upgrade the speakers as well but may not feel the need to once the Prima is installed.)

Because the Prima installs very late in the signal chain, all of the car’s COMAND functionality is unchanged.

I decided to use an extra outboard amp to drive the existing factory subwoofer on the rear shelf rather than an aftermarket subwoofer box. While I was prepared to go to a box if necessary, I found the factory sub performed well on its own amp and left it in place. Saved some money and maintained the factory look of the system.

The Prima accepts high level (powered) inputs, which is essential since the factory Harman/Becker amp is fiber optic on the low level side. Great for no noise but impossible to splice into. Taking signal from the high level side is the only option.  The Prima drops the incoming voltage back to line level, removes the factory EQ, and then applies a suite of powerful, adjustable signal processing tools.  Because the factory amp has a dedicated channel and dedicated wiring for each individual speaker in the car, it just becomes a matter of choosing how to best utilize the Prima’s 8 channels, and routing those channels from the OEM amp’s outputs to the Prima’s inputs, and back from the Prima to the car’s speakers.

Yes, Tons More Volume!

These Go To Eleven!

Clearly owners feel there is a lack of volume in the stock system, since I get that question a lot. The Prima as I have it configured, plus the little 300 watt sub amp, is loud as hell. I’ve played drums in rock bands professionally and for fun since I was 16. Trust me when I tell you I know “loud”. Also, I’m probably half deaf from playing drums and the Prima is still louder than than I’d want to listen to for protracted periods. But the Prima’s real advantage is the digital signal processing and the ability to precisely shape the sound. The power boost is a nice side benefit.

To a certain extent, it’s impossible to get good performance from good speakers without feeding them a decent amount of power, but it’s so easy for manufacturer’s to play with amp wattage specs because that’s all 90% of buyers care about. What matters as well is the speaker’s loads and resistances (measured in ohms), and the speaker’s rated efficiency. For example, as a matter of physics, an amplifier rated at 100 watts per channel into 2 ohms is producing closer to 50 watts per channel into a 4 ohm load (the conventional resistance of automobile speakers) and 25 watts into an 8 ohm load (the conventional resistance of home audio speakers). Likewise, a speaker with a 97db efficiency rating will play louder given the same wattage as one with an 87db rating.

Remember too that an amplifier rated at 100 watts per channel playing at a normal or even moderately loud setting is likely producing less than 40 watts per channel at that volume level.

So try not to get hung up on amplifier wattage as a measure of quality or loudness. An honest 35 watts per channel over 8 channels into a 4 ohm load (the Prima’s rated output) with high efficiency speakers is plenty of power for an environment as small and insulated as a car’s cabin, particularly one like the S/CL.


The Prima comes with several built in, selectable configurations, however Preset 5 works best for the W221. That configuration assigns an independent channel to each of the six front door speakers, and another channel for each two way component set in the rear doors. The OEM subwoofer output gets routed to the Prima’s 9th channel and then to a small sub amplifier. This allows you to use the Prima’s DSP to precisely control the sub,

Click the image to open in full size.

This configuration leaves the dash center speakers (a midrange and tweeter) and the rear deck midrange surround speakers on the factory amp. They blend perfectly with the Prima’s output, but cannot be controlled individually by the Prima.

The Install

I recommend having an authorized Audison retailer handle the installation, because it’s a bear.  My shop chose to build a simple amp rack and locate it in the vacant space on the passenger side of the trunk against the rear seatback. The speaker outputs from the OEM amp were cut, new leads soldered on to extend them over to the new amps, and the process was repeated to send the signal back to the car’s speaker leads. They did a first class job and spent a lot of time. Here’s the Prima installed against the rear seatback and the small 300 watt JL sub amp.


The factory amp. The blue wrapped cables are new and carry signal to and from the Primaimage3.JPG

Once the trunk liner was reinstalled there was no visible evidence the car had been modded at all.

Now the real fun began. The Prima is configured by connecting a Windows laptop to it via a standard USB cable. The installer routed the USB cable into the cabin between the rear seats in the nook for the armrest, and coiled it up under the cover for the fuse panel that lives in there. A simple 6′ extension cable allows you to sit in the drivers seat to set up the system. The Prima’s Windows software comes with the unit on a CD. The following screen grabs show the settings for each speaker set.

Tuning The 221
There’s some technical stuff that may not be familiar here, however if anyone actually does this mod and wants this tune, the entire configuration can be downloaded from the link at the bottom of this post and you can skip this bit before it causes you to fall asleep.

I start tuning at the bottom, literally, and work my way up, beginning with the bass or “kick” drum. I want ito hear it distinctly rather than it being mixed into a lot of bass and midbass slop, and I want to physically feel it “hit”. Here’s the sub’s tuning. It’s cut off very low at 50hz (meaning nothing over 50hz gets to it) Human hearing begins roughly at 20hz on the low end. A 50hz cut off allows almost nothing but kick drum in the subwoofer. As a result I can keep it very clean, powerful and distinct without boominess. A little EQ to emphasize the “hit”.

Click the image to open in full size.

Next I want the bass guitar (or low octave keys and synths) to be heard so that I can pick out the actual bass player’s performance in the mix. The front door subwoofers get a band pass filter and play a range between 80hz and 800hz. Some EQ was used to beef up the 50hz to 200hz range. Although the 50hz range is actually below the 80hz the band pass filter is set to, there is a 12db roll off between bands so some lower stuff does sneak in there.

Click the image to open in full size.

The rear doors are actually the only “full range” speakers in the car, but I just wanted them mainly for midbass reinforcement. They start out fairly low at 100hz and play all the way up to 20,000 htz (the theoretical high frequency limit of human hearing) but they’re equalized to push the midbass and kill most of the mids and highs. I could have cut them off on the high end way sooner but I want a little bit out of the tweeters for ambiance.

Click the image to open in full size.

Between the rear deck sub, the front door subs and the rear door components the bottom end is taken care of. Next is the midrange.

The midrange is where most of the melodic instruments (guitar, keys etc) and vocals are. If it’s not represented well, performances will sound flat and lifeless. If it’s too hot, the lead guitar, horns, higher octave synth and vocals will sound brassy and harsh. Because of the limit on available powered channels, four speakers bypass the Prima and remain on the factory amp (a mid and a tweet in the dash, two 4″ mids on the rear shelf.)All of those speakers play in the midrange. Those 4 speakers form the surround circuit for the Logic 7 multichannel synthesizer. With Logic 7 activated in surround mode, signal is boosted to the center dash and rear surrounds. This brightens up the mids and also lifts the soundstage, so there is already plenty of mid in the car by design and it became more an issue of controlling it.

The mids in the front doors are band pass filtered from a relatively high 800hz right up to the 3000hz point, where the tweeters begin, but their volume level is decreased by -7.5db. That gave me the presence I was looking for but the 7.5db attenuation pushed the harshness down.

Click the image to open in full size.

The tweeters pick up everything north of 3000 hz up to 20000 hz. I have Focal tweeters that are a little aggressive so they’re pushed down 3db as well. The tweets are almost all cymbal sound.

Click the image to open in full size.

When I’m fine tuning my logical frame of reference is the drum performance, since I know what drums sound like live and in the studio. It actually works out, since drums have the greatest dynamic range (soft vs loud) and they play across the frequency spectrum with the bass drum at the low end and the cymbals at the high, with the snare and toms filling out what’s in between. I’ve found that once the drums are “right”, the other instruments also sound right as well.

The Results

This was the astonishing transformation I’d been looking for. Plays very loud and very clean with lots of low end grunt, beautiful midrange and high end detail and a wide sound stage. I have to credit the Focal KRS100 components for the overall quality of the midrange and highs. At $750 they should sound good, but I’m glad I spent the money. Most surprising was how well the Hertz DSK 653 two way components ($79 set) sounded on the Prima. In the stock set up the rear door speakers get relatively little signal and I didn’t want to spend a ton on them. But on the Prima, where they can be set for a full range signal and full power, they contribute a lot of the clean, smooth midbass I was hoping for.

The three orphaned speakers…a 4″ midrange and 2″ tweeter on the dash, plus two more 4″ midrange speakers on the rear deck, remain on the stock amp so they’re only affected tonally by the bass/treble controls in COMAND. Still, they blend in perfectly. I use the Logic 7 fake surround  mode because it pushes more signal to the center dash and rear deck speakers, which lifts the soundstage from down low on the doors where the main 4″ speakers live to up on the dash where it belongs.

My custom Prima configuration file for download. Saves you having to play with all those buttons and sliders:

Prima Config For W221

Some handy PDF’s:

The Audison Prima 8.9 Users Manual: ap8.9_bit_user_manual

The 221’s Speaker Wiring color codes and schematic:Wiring diagram of loudspeakers


Prima 8.9, $900, JL sub amp, $350, Install and materials $600.

Previous upgrades: Focal KRS100 speakers $650, Hertz 6.5 components, $79, MTX 4″ coaxials  $50, Hushmat sound deadening and labor $500. Scroll to the bottom of this blog for details on the speaker upgrades.

Budget Version:

1) Just do the Prima and leave the factory speakers in place. The Prima has more than enough processing power to get good results from the factory speakers. Had I done the Prima first, I may not have done the speaker upgrades.

2) Do speaker upgrades using less expensive speakers. Here’s a write up on some bench testing I did comparing the OEM Harman speaker with very inexpensive off brand speakers:

A couple weeks ago I was browsing a wholesale speaker component catalog (what can I tell you…I’m not a big sports guy and I need something to read in the crapper when my wife throws away the Victoria’s Secret catalogues) and I came across the Goldwood GW-204 4″ woofer. Goldwood typically makes 8 ohm drivers for home speaker building, but the 204 is a 4 ohm version, which is the standard for car audio.

Click the image to open in full size.

As you can see, the Goldwood is quite a bit heftier than the stock Harman 4″, with a huge shielded magnet and motor assembly. Some of that heft is actually the shielding but overall it’s quite a bit more robust. But the best part is that the speaker cone on the Goldwood is conventional treated paper while the Harman is a plastic coated aluminum material Harman calls “Alumaprene”. The metal cone material is why the Harman system sounds as thin and harsh as it does. There are five 4″ Alumaprene speakers, and two 6.5″ Alumaprene speakers in the W221.

I went ahead and ordered one and did a quick A/B listening test, adding a 1″ silk dome tweeter to replicate the set-up in the front doors of the 221. My concern was that the much heartier Goldwood would be a power hog, but it was fine, taking only a little more volume than the Harman. It sounds warm, full and even develops a bit of midbass where the Harman bottoms out and distorts. Paired with the tweeter it sounded great. I wouldn’t hesitate to install the Goldwoods in my car.

Mounting wise I tested the depth in my spare 221 front door module and it’s fine. The Goldwoods (and every replacement 4″ including my Focals) have a square 4 hole mount, where the stock speaker is a 3 hole triangular mount. You’d need to Dremmel off two of the mounting ears, like so:

Click the image to open in full size.
Goldwood on left.

Now the price. Understand that Goldwood has no marketing expense at all. They don’t have the hype of a name like “Bose” or “Harman/Kardon” where they could charge exorbitant prices for otherwise cheaply made components.

The Goldwoods are $22.56. For a pair. If you want to buy four and replace the two surround speakers on the rear deck, the per unit price drops to $10.19.

Link: http://www.parts-express.com/goldwoo…4-ohm–290-370

Here’s a matching set of 6.5’s for the W221 rear doors, $46.20 for the set.

Link: http://www.parts-express.com/goldwoo…4-ohm–290-35

The $49 Glove Box EQ Mod, and a $189 DAC for Apple Devices

This is my all time favorite W221 audio fix just in terms of pure bang-for-the-buck. It does have some limitations, but if you can live with those, you’ll be amazed at how good your system sounds, It’s also about a simple a mod imaginable and can be done without tools in about ten minutes.

  • This mod requires that you have a 12v power source and an aux-in connection to the car in proximity to each other. In the 2010+ W221 that would be in the glove box.
  • It will only affect sound for the aux-in jack, so none of your other sources will be improved.
  • You’ll lose the ability to control your device in COMAND, so the device needs to remain accessible in the cabin. (See prior post about mount options.)
  • No song info will display on COMAND.

The heart of the mod is the Clarion EQS746, a great sounding compact 12v 7 band equalizer. You’ll need a few bits from Radio Shack as well.

Set up is pretty straightforward.

  • Connect a positive and negative lead from a 12v cigarette lighter adapter to the + and – posts on the EQ.
  • Run a short jumper wire from the + terminal to the Remote terminal on the EQ. (Unit won’t power on otherwise)
  • Run a long RCA Stereo male (Red & White) to 3.5mm male stereo jack Y adapter from the “Main In” on the EQ out jacks into the cabin wherever your phone will be.
  • Run a short RCA Stereo male (Red & White) to 3.5mm male stereo jack Y adapter from the Front (or Rear) output of the EQ to the female Aux In jack on the car.
  • On the EQ, set the Fader fully to whichever output you connected to..Set Volume to full.

Bam! Now you can fiddle around with the EQ knobs and get exactly the sound you want EQ knobs 4, 5 and 6 should be turned all the way down to compensate for the Alumaprene speakers. Connect your phone’s headphone jack to the cable and you’re in business.

User comments:

“I read your post over the weekend and ordered the same EQ. Just installed it and it made a tremendous difference (thank you)! Before the volume was so low that I couldn’t hear PANDORA w/out turning up the volume so loud that I got feedback through the speakers from the engine. This has solved 95% of that problem (thank you again, I can listen to PANDORA again)!!! I recommend this upgrade (very easy to do). This weekend I’m going to add a 12 volt plug in the glove box so I can plug my phone into the one near the shifter. Thanks again for all the detailed info!”


“I did this over a weekend ago. Bought the EQ, noisefilter, and bluetooth adaptor.
Pandora from the iphone5 to the bluetooth sounds fantastic !!!.


“I went to an audio shop to have it done. I did this because the first Radio Shack store I shopped at didn’t have all of the parts and I didn’t want to spend the time to track down which stores did and drive around to get them. I figured an audio shop would have the necessary on hand, and they did.

When I told the audio shop owner what I wanted to do, the response was along the lines of “You’ve got a $70000 car and you want to ***k it up with a $50 piece of ***t?” and “I don’t recommend you even try this.”

When I told him to go ahead anyway and that I could simply remove it if I didn’t like it since there were no holes drilled etc. he gave me a look like “OK, idiot, I will take your money if you insist.”

When it was all done he was quick to admit he was wrong and that the mod made a significant difference. It was my turn then to give him grief (with a smile) about how he was too quick to be harshly critical.”

For detailed set up and additional add-on options check this thread:

Add In A DAC For Even Better Sound,,,

If you’re using an Apple device, you can get even better sound quality using an outboard DAC (digital-to-analog convertor). The DAC is the circuitry that takes your digital media files and converts them into analog sound for playback. It’s a pretty important part of the process, and its usually handled by a little chip in the device itself. A dedicated DAC features heartier circuitry and will give you a more high end sound from your digital files.

Another benefit of the DAC is that it bypasses the little headphone amp in the device entirely, which also improves fidelity. The IStreamer 12v by High Resolution Technologies is a great sounding external DAC and one of the few I’ve found that will simultaneously charge your Iphone while its playing. The mids and highs sound especially good on the IStreamer, and the sound overall feels more open and airy.

To add it to your EQ mod, run a charge/sync cable from your device to the USB input on the Istreamer. Run a standard RCA stereo cable from the Istreamer outputs to the EQ Main In inputs and enjoy. (You’ll also need a USB power supply in the glove box to power the Istreamer)

Iphone: Streaming Bluetooth, Mounts

If you use your Iphone as your music player, there are a couple of options for connecting with the car. For connecting via Bluetooth Audio, which the S Class lacks, the Tune2Air adapter works wonders. Its female 30 pin input mates with the car’s Iphone cable. where it draws its own power. The Tune2Air is then paired to your device. If it’s an Apple device, you’ll have all of the functionality of a direct connection, including COMAND display of track and artist, and steering wheel controls.

Of course, it pauses and mutes when a call comes in, and if you leave and return to the car it pairs automatically and begins playing where it left off.

Available on Amazon here:

Tune2Air Bluetooth Audio Adapter ($80)

Tune2Air Bluetooth Audio Adapter ($80)

There’s some debate about the quality of BT audio versus a direct connection. A lot of the confusion stems from failing to understand that BT audio and the BT connection for your phone are completely different, independent systems that both happen to share Bluetooth protocols.  So while phone sound in the car is universally terrible, BT audio can sound as good s a wired connection in most cases.

The current protocol for BT audio is A2DP. A2DP is a full frequency range system, however it does use a form of compression to make streaming possible.The current default compression system is SBC. All devices transmitting and receiving BT audio must support SBC at a minimum.

SBC has an effective bitrate of 328 kbs, which from a digital file compression standpoint is quite high. Music on your device encoded at 320kbs or less should play back with no audible compression artifacts. However, not all BT audio playback circuits are created equal. Apple device, especially the 5 and 6 series, have excellent, natural sounding BT audio output. The Android devices I’ve auditioned did not.


The other option is a direct connection to the car’s IPod cable and a device mount in the cabin. I use a hybrid of two mounting systems: A W221 custom mount by Kuda (available in Black, Gray and Cashmere), and an IPhone cradle by ProClips USA. To route the connection from the cradle to the car’s very short IPod cable, I use a dock extender (basically an extension cord) by CableJive that runs into the glove box with a female end that connects to the car’s Ipod cable. If you have an Iphone 5 or above, you’ll need to add a 30 pin to Lightning Adapter at the Iphone end of the CableJive dock extension cable.



ProClips IPhone cradle mounted directly to the face of a Kuda W221.

CableJive Dock Extender

CableJive Dock Extender

Of course, you can have the best of both worlds by using the cabin mount as a charging station only, and connecting the device via Bluetooth Audio.

Love The Car… Hate The Stereo? Read On.

It’s hard to complain about a world-class German luxury sedan like the W221 S Class, but I found a way. The audio system just isn’t up to par. I can think of several adjectives that describe the output of the stock Harman/Kardon Logic 7 stereo. Thin. Shrill, Weak, Hollow, Pick one or pick them all.  The culprits are an overly bright and metallic midrange sound, underwhelming bass, and insufficient tone control range on the head unit (COMAND).

One problem lies in Harman’s odd choice for a speaker cone material used extensively in Mercedes Logic 7 systems, called “ALumaprene” or “Metal Matrix”. The other is a factory EQ that strips the balls out of the car’s three (count ’em!) subwoofers and replaces it with overwhelming mid-range slop.

Alumaprene , as the name implies, is a plastic coated metal material. Not surprisingly, it’s very stiff and produces a thin, metallic tone.

The good news is that replacing the Alumaprene speakers cures a lot of the Logic 7 system, can be done in phases, and isn’t especially difficult or expensive.

The Alumaprene speakers in the W221 are as follows:

  • (1) 4″ speaker center dash
  • (2) 4″ speakers front doors
  • (2) 6.5″ speakers rear doors (A 4″ speaker is substituted here for the CL)
  • (2) 4″ speakers rear parcel shelf

A 4″ speaker is going to sound midrange heavy anyway, so building a 4″ with a metal cone and then installing five of them in the cabin seems like a really bad idea.

A typical Harman Kardon ALumaprene speaker.

A typical Harman Kardon ALumaprene speaker.

The other speakers in the W221 are:

  • (1) 1″ tweeter center dash
  • (2) 1″ tweeters mirror sail panels
  • (2) 1″ tweeters rear doors
  • (2) 8″ dual coil shallow mount subwoofers front doors
  • (1) 8 x 12″ dual coil shallow mount subwoofer rear shelf.
An 8

An 8″ dual coil subwoofer from the W221 front door module.

The tweeters are off-the-shelf silk dome style car tweets, and aren’t objectionable. The subs in the doors and rear shelf are a proprietary Harman design, which makes them a challenge to replace (although both Focal and Gladen sell a drop in replacement for the 8″. Forget the 8×12).

I’ve found that the subs are actually salvageable, and will play clean midbass and pound away at the bottom end with a good deal of authority in the right conditions. The primary condition is that their enclosures are heavily covered in a sound deadening material to eliminate rattles.

Then , and only then, can you feed them sufficient bass either using the tone control on COMAND, or using a source that has adjustable EQ (recommended), or a combination of both, without causing sympathetic vibrations (rattles) in the car’s cabin.

My S550 Logic 7 Replacement Speakers

When choosing replacement speakers for an OEM system with a stock amp, it’s important to avoid the temptation to go with heavy power handlers. Generally, a speaker capable of handling a lot of maximum wattage also require a lot of nominal wattage (the minimum required for them to perform properly.)

The S Class Logic 7’s DSP amp is rated by Harman at 600 watts into 4 ohms, which isn’t horrible in terms of power. However, that 600 watts is spread over 7 channels and 14 individual speakers. The bulk of the power is directed toward the three dual coil subwoofers, and most of what’s left is directed to the front door speakers, then the rear doors, and lastly the two 4″ surrounds on the back deck and the 4″ surround in the center dash.

You may be inclined as I first was to contemplate replacing the amp with aftermarket. Here’s what you’re up against:

  • The stock amp is part of the Audio Gateway, a master controller for the other audio components (navi, voice command response, phone). It has to stay.
  • Bypassing the amp is a challenge because the low level inputs, which you would normally split off to an aftermarket amp, are all on a single  fiber optic cable into the Gateway.
  • There are currently no 3rd party fiber-optic to analog converters for the W221 capable of taking the fiber optic signal and decoding it into multi channel analog audio.
  • Taking the signal for aftermarket amps from the high output, speaker level signals coming from the Gateway requires line level converters for 7 channels plus the sub for passive crossover in the doors, or for 14 channels for active crossovers in the doors.
  • There are currently no 3rd party DSP (Audison Bit1, etc) processors capable of 14 channel ouput.


Phase 1

I left the amp alone and instead put some real money on the front door 4″ component speakers. I chose Focal’s K2 Power Series KRS100. ($749)

The Focal KRS100 2-Way Component Speaker System

Focal KRS100

You get a nice 4″ woofer, two 2″ tweeters and an adjustable external crossover. At $749 they’re not cheap, but they sound terrific. Very clean, powerful and detailed. Never too bright (see the note below on the crossover setting).Night and day from the 4″ Alumaprene speakers and an excellent compliment to the 8″ door subs. I chose to flush mount the tweeters in the mirror sail panels because they look kind of cool, but they can easily be installed behind the grilles.

Focal Tweets & Badge

Focal KRS100 tweeter flush mounted, and a Focal badge thrown in for good measure.The doors of course got a heavy Hushmat treatment to tighten the midbass and kill rattles.

Factory Door

Factory Door


Hushmat door treatment and Focal midrange installed in factory module.

A note on installation of the KRS100. The crossovers have a selectable midrange boost switch and you want it set to”HI”. Initially we presumed “HI” was more boost, which we absolutely didn’t want. It turned out that “HI” presumed the midrange speakers were positioned high on the door so no midrange boost to compensate for upholstery and carpeting down low was necessary. Also, the mounts required a little surgery (see pic)

To change from the square 4 hole mount to a triangular mount, two ears were removed and a clip was fabricated.

To change from the square 4 hole mount to a triangular mount, two ears were removed and a clip (bottom screw) was fabricated.

Phase 2:

I lived with just the front door upgrade alone for awhile and then decided to do the rear doors. The 6.5″ two ways in the door get relatively little signal, so I chose not to spend a lot and went with the Hertz DSK 6.53. Again, replacing the 6.5″ Alumaprene speakers resulted in a much warmer, natural tone with no excessive brightness or harshness.  The rear doors received full Hushmat treatments as well. Any decent 6.5 component speaker would work in the rear doors, (or even an inexpensive coaxial). Just watch the efficiency since they don’t get a ton of power.



Hertz DSK 165-3

Phase 3:

With the vastly improved and rattle-free bass response from the doors, I was able to put more bottom into the sound, but the 8 x 12″ sub on the rear deck rattled like crazy at certain frequencies, so it had to get the Hushmat treatment. Accessing the rear deck requires some interior removal and took the shop a good bit of time. Since they were in there anyway, I replaced the two 4″ Alumaprene  surround speakers that flank the sub with inexpensive MTX TDX40 coaxials. ($49) They’re quite a bit warmer and smoother than stock. You’ll hear the difference when the Logic 7 surround circuit is active.



Phase 4:

With the speakers sorted out I turned my attention to getting the best source sound possible. While the internal sources (disc, register, radio etc) sounded much better post-mod, the COMAND’s very limited Bass/Treble tone controls were lacking. What it really needs is a Midrange control, because the factory EQ is so mid-heavy to begin with.

That left me with using my Ipod/Iphone, and its internal EQ presets to get more control over the equalization. My library is local, 256kb AAC. I found that the “Bass Boost” preset was the most pleasing sounding, but none were ideal.

That lead me to the AudioForge Equalizer app ($2.99), which allowed me to create an infinite number of custom EQ curves and ultimately settle on one that sounded good on all of the material in the library. If you do this mod and would like my optimized S550 EQ setting for your car, AudioForge allows sharing of custom EQ presets.

It also has a couple of features that are really useful. “Auto Normalize” continuously analyzes the audio stream and adjusts the pre-amp level on-the-fly. The result is much higher volume output without clipping or distortion. “Crossfade” will simultaneously fade out the end of the current track and fade in the beginning of the next track for a seamless listening experience.

Note that the app only works on your local library, not streaming or cloud content.

The AudioForge EQ app

The AudioForge EQ app

 The Results:

Astonishing. If I demo’d my Logic 7 system for you and told you I’d gutted the car and replaced everything, amps and all, you would have no problem believing me. It’s clean, detailed and precise in the highs with great imaging. The mids are prominent but not thin, harsh or brassy. The midbass is clean and balanced with a defined “hit” you can feel in the seats. The low end is powerful but not loose or boomy.

In Logic 7 mode, the sound stage is lifted considerably, and the listening space seems to swell to several multiples of its size.

I guess the simplest way to put it is this. Do you ever reach your destination and then just sit in the car, parked, so you can continue to enjoy your music? I do all the time.