Lcls

Hello, I am starting this thread to detail the installation of an amp and subwoofer to a 2014 E350 Sedan with the HK system. I’ve seen several different threads regarding these kind of installations and wanted to put my own spin on it. I will be installing a 12” JL audio bass wedge, JL audio amplifier, as well as a custom mounting solution completely hiding the amplifier. Looking forward to sharing this with you guys in the next two weeks!

OM651

Interesting following this. Going to do about same install for mine W212 later 👍

Lcls

Ok, so the first steps were accomplished tonight. I started the process of determining the signal to use for the aftermarket amplifier to be installed. I had a few concerns, first the signal itself and the crossover frequencies being used by the HK system, secondly the wiring schematic. I purchased a used non-working HK amplifier (subwoofer) and took it apart so I could obtain a male plug and test all the wiring in the harness and built a simple RTA cable to plug into my iPad to analyze the signal. I also tested all the wiring as well in the harness. The pinout diagram that is attached provided the wiring locations but not the correct wiring colors. Its for a different model Benz but the wiring placement is identical, use the below information at your own risk, test out the wiring like I did.


Here is the male plug (amplifier side) and the wiring schematic- I did not put colors since they vary sometimes by model

Below is the RTA cable I made and the frequency recorded from the subwoofer input signal wire

This is a simple RTA cable that plugs into my ipad to analyze signals - if you would like instructions on how to make one just PM me....cost me about 50 bucks in total

This was the frequency response from the subwoofer signal wire going into the HK amp


More to come, the last thing left for me to do is measure the voltage of the signal feeding into the HK amp, I will be doing that sometime this weekend and will post the results.

tpdtopcop

Great. I am just looking to get old speakers, amp, and sub out to replace?

Lcls

I don't think that's possible with the Harmon Kardon system, the amplifier controls several other systems from my understanding, you can replace the speakers and sub and add amplifiers but you have to keep the HK amp from my understanding to use as your signal source.

Lcls

Ok some additional progress tonight, I built a custom T harness from used parts that allow me to obtain both the signal and remote wires without tapping into or cutting any of the factory wiring. Also below is the beginning of the mock-up of the amp rack which will also have a custom on/off switch. I haven't measured signal voltage yet and will do so shortly so I can adjust the Converter and Amplifier gains and boost.

Doctor Bob

Wow, that looks really professional and clean so far.

botaggs1

Hello - do you have an update on this? How did the rest of the install go? I'd like to follow a similar path of upgrading through that plug next to the small fan on the rear deck (assuming this is the subwoofer amp). My questions are, did you disconnect the OEM subwoofer entirely, or just split the signal between that and your new aftermarket sub? Also, would this affect the rear deck speakers, as in do these speakers also get their signal through that subwoofer amp? It looks like they might as I had the rear speaker panel off and saw two plugs on either side of the OEM subwoofer, assuming these were powering the left and right rear deck speakers.

Lcls

So I do have an update on this, I ended up having to tap in a different route in order to obtain the signal, as well as the remote turn on. There are a couple of quirks I discovered the process:

• The Factory Subwoofer interfered with the sound quality- ended up disconnecting it completely
• Tapping into the wiring on the subwoofer harness ended up causing noise issues-
• There is one set of wires out of the HK Factory amp that will provide signal and remote turn on
• The wires are Brown/White/Black and merge into a single black cable that runs to the Sub amplifier
  • Brown/White Signal
  • Black Remote
• Utilizing the signal wire to auto turn on the amplifier can cause noise/popping sound issues.

Let me know if you have individual questions feel free to reach out, ive also attached pictures of the remainder of the install

Fuse Holder 4 GA

JL Audio JX500.1 and JL Audio LOC-22

Blown PVC amp rack- Attached to XM satellite module bracket behind Factory Amplifier

Amplifier placement with factory amp mounted

Amplifier placement with factory amp mounted

botaggs1

Thanks for getting back. I actually took a different approach. I had originally tapped into the white and brown low-level signal going to the subwoofer cable but felt that the sub sounded too boomy and mismatched, even with my gain very low. So I ended up cutting the 4 OEM subwoofer output cables and attaching them to RCA's which then ran directly to my amp (JL XD300v2), while also tapping into the one black wire for remote turn on (also found this to be much more reliable). I found that this sounds really good for my purpose, as the OEM subwoofer is disconnected, however, the signal is still passing through the subwoofer amp. For some reason, I think the improved sound is because the subwoofer amp is doing some sort of processing, time correction, and/or crossover matching that allows it to blend more seamlessly with the rest of the system. This thought, however, is completely unsubstantiated and just something I tell myself, LOL. I did not use a line output converter, however, as my JL amp can accept the high-level signals. Out of curiosity, may I ask why you chose to use a LOC, I believe the JX series accepts a high level as well?

Lcls

So I ended up using the LOC for a couple of different reasons, first was the ability to adjust the output level of the RCA's into the amp, and secondly I was going to use the remote turn on feature(did not work due to popping noise on shut off). I'm running a JL 12w3 and have the gains on the amp set at the lowest possible settings and adjust any signal strength through the LOC and it works extremely well for me. I don't have an issue with it being bass heavy its almost spot on, I ended up not using the bass knob at all and I'm overall pleased with the sound.

nizzle

So for constant power your connected to your aux battery in the trunk?

Lcls

Yes, I ended running a 4GA from the aux battery to amp, obviously with a fuse holder. The obviously proper way would be to run it from the main battery in the front to the rear, but this was much simpler and with the amount of current draw I've had absolutely zero issues. My amp is set a almost zero gain and I'm running a single subwoofer that's pretty efficient. Anything more than that or multiple subs I would definitely run the power to the front.

Dr.Alberto

I will be looking forward to your updates as I am considering upgrading the sub as well on mine. Best of luck

CaliBenzDriver

LCLS:
The way the cabling looks... you are taping power directly from the post of the AUX battery, right?
Have you noticed anything weird as far as power goes??

Doing that must drive some crazyness in the system that's wondering where all the AUX battery charge is going... this battery is used for secondary supply during ECO cycles.

Why not tap directly the main battery nearby ?


Use of BCM relay posts
Tap BCM Relay #2 post to feed directly from the Prefuse that supplies R-SAM.
It's better than #1 post... that is cut off internally by BCM MosFet relay.


FYI FLOAT/CHARGER TIP:
You can use these two BCM posts to simply charge both batteries individually without ever opening the engine hood...

tkelley.EClass

Hey Folks, reviving an old thread here. @kennyd did an amazing write up on installing a sub in his E63 here on YouTube:
Question, based on the above image, should I actually be tapping into the power source on the side of the battery versus the top? Or does it not really matter? I'm basically cloning what Kenny did, it's too damn easy and I'd love to get this done in an afternoon!

CaliBenzDriver

NOP! LEAVE AUX CIRCUIT ALONE... ✌️

OMG ....
Tap the trunk incoming power feed from the front, not the AUX Batt.

Simply use the relay post located by AUX side (shown in previous posts).


Ref. prev post: #2 your friend

What you want to limit current ripples for deep bases is a low impedance power supply. The best one is the most direct to the source which at the end of the day is ALT, not Main AGM.
A Farad capacitor can help pack DC punch.

If you want a bit more quality in your build... run your own cable to the front prefuse.
This prevents introducing a lot of ripples directly into REAR-SAM... the VIP Module in charge of 12.6V regulation. SAM feeds at AUX relay, exactly were you are taping incoming DC power...

By running your own cabling you don't tax existing that you can trust is bare-bone sized.
You can start simple then later run an upgraded feed to the front - In the mean time be on the look out for what craziness R-SAM brings to your car when it gets glitched silly.

----------
Basic choices...
EASY: tap incoming feed on AUX side relay.

BETTER: tap the front PREFUSE where the rear cable feeds or ALT incoming post.

Can any combination provide power: yes certainly does.
✌️

Siegmann

Does anyone have a DIY for running power from the main battery?

Left Coast Geek

power in a car actually comes from the alternator, not the battery. but unless you'll pulling 100 amps or something, if you need power in the trunk area, I would tap the power wire connection on the rear SAM that comes from the main battery as shown in the previous post.