Like many of you I was greatly dissappointed when I dropped the top of my shiny new SL, got onto the Freeway and flew way past the posted speed limit, and then went to turn up my favorite tunes only to be shocked that the only sound came from in front of me. It was only my 3rd or 4th day of ownership that I started searching as to why a six figure sticker price car has rear speakers that don't work.

I read the threads on this forum in detail and tried to use the Best Buy upgrade but couldn't find a Master Installer. So I undertook the task myself. I have tried to put step by step instructions together so that others who want to fix this issue can do so. I have a 2017 SL450 with the Harmon Kardon sound system. I do not know how far back in the SL lineage these instructions work in regards to the colored wires I identify to splice into.

I did this upgrade in Nov of 2019 and soon after my Dad had a heartattack and I had to drop everything and go take care of my parents. Here are the first steps to the project. Please let me know if these instructions are worthwhile. It takes some time to put these slides together. So if this isn't usable let me know before I invest further time.

Dave B

 

 

 

 

 

 

 

 

 

 

YES! Extremely helpful! PLEASE continue and thank you very much!

 

Did you try the Pasadena Best Buy?

 

o2manyfish, what an outstanding presentation. Well done. Anyone who fears doing this job themselves can surely take your 10 step presentation to any decent installed and have the job performed correctly and properly.

Thank You

 

Am I missing something, or wasn’t there supposed to be more “episodes” to this thread?

 

Yes, I need to finish the tutorial. But between Pandemics, and struggles with a brain injury, there just isn't enough time in the day.

But I will put it on my to-do list just for you

I think I am going to pull the rear area apart again and upgrade the speakers in the rear. You could come by when I do mine and play the copy cat game --Just Do everything I do, but better! --lol


PS -- I thought you were selling the SL ?

Dave B

 

Thank you o2! Very comprehensive and am going to give this link to SOMEONE (Still need to find that someone) who can do this. And BRAIN INJURY? Man hope you are doing well- Love your Color BTW! I have the brilliant blue also without the chrome bits.

 

Sorry to hear of your injury. Hope you are past that now. I’ve had some health issues of my own recently and I posted the SL for sale during a low point in that experience. Been recovering over the past few weeks. However, as I fully expected, nobody is willing to pay for the upgrades, so I don’t see MM flying off anywhere soon. So, might as well fix the audio! I, myself, am not up to the task, but if your “mini series” gets completed, it sure would be a big help in showing a shop what I want done. Would love to see you do the subwoofer as well. Looking forward to seeing your progress and thanks again for doing this.

 

EXCELLANT!!

 

Great job thus far. I too am waiting for the rest of the installation directions.

 

I have a 2013 SL63 with HK/Logic 7 and want to do this mod.
I've entered "Engineering Mode", enabled the balance/fade control.
However, I'm still not clear how the Alpine amp should be wired...
Is it;
1 The output going to the front speakers is tapped into, fed to the Alpine amp and then connected directly to the rear speakers, thus by-passing the Mercedes amp rear output completely.
or
2 The Alpine amp is installed between the Mercedes amp and the rear speakers such that it just amplifies whatever is already being being output to the rear channels.

One of the reasons I'm asking this is that the Alpine 445U or 450 are very difficult to find here in the UK. I may have to use Pioneer or Sony Class D amps which are very similar but do not have a gain control built in.
Thus option 2 above appeals because I can use the cars built in balance and fade to vary the rear volume.

Hope this makes sense and would appreciate any help.

Russ

 

So, Mr. o2manyfish, I hope you are feeling much better and have been enjoying your lovely SL. I took mine out just yesterday, as there was this hint of fall in the air and the temperature was perfect.

Any thoughts on completing your truly magnificent installation guide? For the most part, I drive my SL with the audio system off, as I much prefer the purr of the exhaust to the noise that comes out of my speakers.

Just thought I’d check in with you. Hope you are doing well.

 

It's been a busy few months for me. Wrapping up my second trip to Hawaii in 30 days. I've been pretty crazy the last few months. But if we get some not so pretty weather I will try to wrap up the installation guide.

This summer I didn't get that much 'FUN' time with the car. The heat in the valley has been just insane so not too much top down driving. When I drive the car I love it. We had to get my wife a new car and got her a couple of year old vette. And being a fat old fart I sure love how much more comfortable it is to get in/out of the SL and just to sit in it. Her vette has the competition seats which are not designed for comfort or my girth. Both are fun cars to drive. But I think the SL in Sport + Mode with the Revs in the turbo range is a much more spirited drive.

Taking my SL in next week for Ceramic window tinting. My car has ultra clear glass and my dogs just cook sitting on the passenger seat. So I'm trying this ceramic window treatment which is supposed to cut way down on the heat transfer without darkening the windows like a limo. Will see how that looks and works.

Dave B


Dave

 

I have been following this thread for a while, and thanks for all of the useful information. It is my sincerest hope that "o2manyfish" is doing well. I had a 2013 SL550 with the optional Bang & Olufsen stereo system, which was nothing short of outstanding. I really liked the cool, light-up droid tweeters on the dash, too. I traded the SL550 for a 2017 SL63 AMG with the standard Harman Kardon system. I was sorely disappointed by the stereo in the new car, especially the complete lack of sound from the area behind the seats, with just about everything except a few random CDs. Thanks primarily to the information posted here, I decided to visit a reputable, car stereo/electronics specialist, where a mini amp was installed in the area under the trim panel behind the driver's seat, adjacent to the storage bin. The rear speakers are now fully active with all audio media, and I find the result to be a dramatic improvement over the factory "flub". Aside from the aforementioned light-up droid tweeter things, I no longer miss the B&O system in the SL550. The amp installed was a Soundigital EVOX 400.4, which was recommended by the technician as being superior to, as well as smaller than, the Alpine unit, about which I had initially inquired. (Shop had both on hand, and they were similarly priced). While most likely not up to the standards of a true audiophile, which I am not, the installation of the mini amp improves the HK system to a level befitting our beloved R231s, IMHO. I'm now much happier (and quite a bit less aggravated) with the stereo's performance. My respect and admiration for anyone who can accomplish this on their own. (Yes, o2manyfish, this means you). After having watched the process, including the panel removal, the fabricating and integrating of the custom wiring harness, and placement insulation for heat management, I can confidently say that this is an undertaking I'm glad I had not attempted!
"A man has got to know his limitations!" -- Insp. Harry Callahan.

 

What is the specific request when you go to a stereo shop? I'd like a better sounding stereo also. Do you just ask for a mini amp installed to drive the rear speakers?

 

Hello,
When I went to the shop, I told the gent that the rear speakers were almost never active, despite the input, as a result of an apparent flaw within the system's design, and that this is a common issue/complaint. I also informed him that the installation of a mini amp to power/activate the rear speakers specifically, was a solution that had worked for others. I referred him to the postings herein, and after doing a fair bit of skimming, he suggested the Soundigital EVOX. The installer was skilled/experienced enough to know how to properly integrate the mini amp into the existing wiring, and now the rear speakers are always active. When the wiring was completed, we fine-tuned the particulars, top up and down, and now the HK system is actually quite nice.
I certainly think it was worth the effort---it made a huge difference in the stereo's overall performance, IMHO.
Best of luck!