Sprinter Stock Stereo Upgrade and Speaker Replacement

Its no secret the stock audio system in the Sprinter is terrible.  The stock speakers are pretty much just recycled paper with a magnet glued to them (not that there is anything wrong with recycling). And the Audio 15 head unit puts out hardly any power. You are left with a tinny, weak sound you can barely hear over the road noise. Originally, I thought that fixing the road noise issue (with sound dampening and insulation) would make the stereo sound better – at least you would be able to hear it. I was wrong, once I could hear it, I knew how bad it was – I couldn’t pretend anymore. If we were going to do long road trips in the van (which was the entire point of having the van) the sound system had to be upgraded!

Lots of folks replace the stock speakers in their vans, realize that the sound from the stock head unit is still not very good (even with better speakers) and then replace the stock head unit with a different unit. We took that route at first too, and its true, the sound is still pretty bad. However, we opted to keep the stock head unit (no complaints about its capabilities to play radio or music over bluetooth) and instead added an external amp, rear speakers, and subwoofer to the mix. This made a huge difference and honestly I believe is the better way to go (if you don’t mind not having a touchscreen head unit – not a problem for us). The cost of a decent amp is similar to the cost of new head unit (including the required amp accessories) and I believe the sound improvement with an amp pushing 300+ watts exceeds the improvements you would get from a new head unit that maybe pushes 100 watts. Plus then you don’t have to deal with rewiring your steering wheel controls or need a new wiring harness, dash plate, etc. So, in summary my recommendation for the money is to add an amp and new speakers to your system and keep your existing head unit. Find out how we did that, below.

Summary (TL:DR):

We replaced the speakers in the front doors, added rear 6×9 speakers and a separately powered subwoofer. We kept the stock stereo (cost, practicality, stock look) but added a 300W amp to power the new speakers. The system sounds great and the install was fairly straightforward. It required removing the stock stereo (though not removing the entire front dashboard) to get at the speaker wiring and removing the door panels to replace the front door speakers. But overall the install process was pretty straightforward and only took about 4 to 6 hours (including a lot of fidgeting, thinking, and theorizing).

Tools:

Materials:

Reference:

  • DirtDevil Build: Lots of good information on taking the front doors apart (and the dash apart which I didn’t do) – see first two pages of post
  • Sound system upgrade: great write up on replacing the door and dash speakers.

The Procedure:

Our stereo upgrade involved sixmain steps (in no particular order):

  • Install the door and dash speakers
  • Intercept the speaker outputs from the stock head unit and run the wiring
  • Install the amp and supporting accessories
  • Install the rear speakers and run the wiring
  • Install the subwoofer

Lets get to it…

1. Install the door and dash speakers…

I won’t provide too much detail on removal of the door panels or installation of the speakers, as that is covered well in the reference articles. As spintervanusa recommends, always start any project involving the van electrical by disconnecting the main van power supply in the driver side foot area, next to the pedals. Then use a torx driver (T20 & T30, I think, for most of them) to remove the screws holding the interior door panel on to the door frame. There are four (4) screws holding the door panel on each door. One on the top behind a little circular plastic cover (i removed these with a knife), one behind the door handle black plastic cover (remove the cover with a trim tool and find the T30 screw deeply recessed), and two more behind the lower storage bins at the bottom of the door (remove the storage bins, they pop right off once open).

Once you undo all the screws, you  need to pry up the little plastic cap surrounding the door lock – again a little knife works well for this. Then start prying off the door. Like so many other wonderful things on the van this is held in by the little plastic pop rivets. You will likely lose or break many of these as you pull the panel off, regardless of how careful you are. I inched my way around the door with the trim removal tools trying carefully not to break any of the green rivets, but a couple of them didn’t play nice anyway. The door seems to stay just fine even without them, upon reassembly. Once the door panel is free from the door frame there are some wires to disconnect for the window controls and lock controls (depending on which door) and also a cable to disconnect the door latch. The door latch assembly is actually kinda tricky to remove – first you need to rotate the yellow cylinder out of its holder (which it was really stubborn about for me – but I persisted!) then pull the l-shaped cable end out from the slot. The easiest way I found is to hold onto the cable portion (just ‘down-cable’ from the yellow cylinder) and pull out (away from the door frame). I pulled pretty hard and managed not to break it, so maybe that’s the recommended method.

Removing the tweeters in the dash is pretty easy too – just use a trim removal tool to pop the black plastic covers off and then remove the one screw that holds them in. Once you see what these speakers really are, you wont be surprised at how crappy it sounds.

Once all the panels and covers are off rip those stock crappy speakers out! Or carefully unscrew them from their respective locations and remove them, politely. In order to avoid having to take the dash completely apart (like they did in the DirtDevil build) I maintained the wiring to the door speakers (woofers) and only replaced the wiring running from the crossovers to the tweeters. This was necessary in order to be able to utilize the new crossovers and really wasn’t so bad. Just run the wires from the door / woofer location through the rubber sleeve where the door connects to the body and then up into the dash. I used a guitar string as a more rigid fish wire to route the wire through, but I can imagine a number of household items could be used. So ultimately I used the existing speaker wires to run to the crossovers and then used new speaker wiring to run from the crossover to the woofer and tweeter.

For the front speakers, I chose the JBL GTO609C Premium 6.5-Inch Component Speaker System. Mostly because they got good reviews, were in my price range and were the right size. The key is the 6.5″ woofer and the 1″ tweeter. Of course you can spend as much or as little as you like on your speakers. This was right for me and they have worked very well, no complaints from me.

Install of the tweeters was easy. They press fit nicely into the existing plastic casing and I soldered the new speaker wires to the speaker terminals. You could use quick connects on these terminals, but I am a fan of permanence, when it comes to things I never want to have to deal with again (and if I do have to deal with it, its not big deal to clip the wires).

Install of the woofers requires installing Hein’s (Impact3D) speaker adapters. The adapters themselves screw into the existing holes in the door panel. Then your new speakers screw into the adapters. I also velcroed the crossovers to the inner door frame, but in a space I am hopeful they wont get dripped on from rain or condensation.

If you haven’t already, it’s a great time to insulate the doors with thinsulate while the door panels are off. The thinsulate should be glued to the plastic door panel NOT the metal door frame. Be very careful not to get the insulation in the way of the window movement.

Test everything out with the stock head unit and once satisfied put it all back together.

2. Intercept the speaker outputs from the stock head unit and run the wiring

Next we need to insert the new amplifier into the equation. The stock head unit delivers practically no power to the speakers and with nice new speakers that have decent power handling, that is no good. But to minimize disassembly and also maintain the stock head unit I “intercepted” the speaker wires from the stock head unit, rather than replaced them.

First thing you need to do is remove the stock head unit, to get at the wiring in the back. Again, any time your messing with electrical, disconnect the van power from the driver side foot well. Removal of the dash surround in the head unit area is easy with trim tools. This short 2-minute video shows the basics of removing the radio. It is showing a little bit different than the stereo on my 2016 Sprinter, but the basics are the same. Remove the black cover surrounding the stereo by prying it up (starting from the top or sides) with a trim tool. It pops right out pretty easily. There is a wire attaching to the lower control module that you can leave attached and just have the whole thing dangle, or unplug. Then its four (4) T-20 screws to remove the head unit.

Once you pull the head unit out you can disconnect it from its various connectors. The big black one is the one you want. Peal back the tape holding the wires into the black connector/harness so that you can more easily separate the wires it contains. You are looking for those same wires you connected the speakers to in step 1. That is, brown/blue, brown/orange, brown/purple and brown/green. All these wires terminate in the yellow portion of the harness (see photos). To simplify wiring everything up, what I did was clip these 4 wires and run new wires back to my amp, then run the output wires from my amp pack to this area to power the new front speakers. So that basically requires eight (8) new wires running to/from the new amp and stock head unit (or 4 sets of 2). I used different color wires where possible, to designate the wires “coming from the stock radio/head unit” versus the amplified wires “coming from the amp”. And also probably a good idea to keep track of left and right and plus and minus too.

I decided to locate my amp in the same little box behind the driver seat that all of my other electronics reside in, but under the drivers seat, passenger seat, or anywhere there is space and adequate ventilation is probably fine. So all the new speaker wires were routed down through the dash and under the front flooring back to behind the drivers seat. Fishing the wires through to minimize the amount of stuff I had to take apart was pretty straightforward (though I did pull up the van floor in the area around the drivers seat to make this easier.

Once all the wires had been run with the appropriate lengths to reach their destinations I made the eight (8) solder connections to the existing wiring in the dash. Since I felt confident in my solder work, I went ahead and put everything back together in the dash – though you may want to test your connections with a multi-meter before reassembly.

That covers the wiring. Next for the amp install!

Install the amp and supporting accessories

Once all the wires are run back to the amp location, its just a matte of getting power to the amp and connecting everything up. However there are a few nuances. Amps are designed for low level inputs, like those from RCA cables. However, since I was using the stock radio/head unit all I had was high level / speaker-level outputs. That requires conversion back to low level for use with an amp. Some amps come with high level converters built right in. The  Rockford R300X4 Prime 4-Channel Amplifier that I purchased did not have this functionality built in, so I needed a separate speaker-level converter. I chose the AudioControl LC2i. This unit is pretty cool as it has 2 channels which can be used to control my mid and high range speakers separately from my sub. Of course, you don’t have to go all fancy like this one, but there are some benefits to individual volume and boost control on each channel, which I appreciated and enjoy now.

The wires from the stock head unit come into the speaker-level converter as “speaker inputs”. Then RCA cables connect the “main output” to the new amp and the “bass output” to the powered subwoofer.


I put together a diagram showing the basic wiring connecting the stock radio / head unit to the new speaker-level converter and then the various connections from the amp back to the existing speaker wiring and also the connections to the new subwoofer (discussed later).

Wiring of the speaker inputs and RCA input/output to their various locations is pretty straightforward – if you can call the diagram above straightforward. But really, as long as you can keep the wires going to and coming from the head unit area, there is not much to worry about. Just get it done.

Things get a little more complicated with running the power. Each unit in the audio system unsurprisingly requires its own power (high level converter, amp, subwoofer) but also requires a signal to automatically turn itself on. It would be annoying to have to manually turn the amp on every time I started up the van and wanted to listen to music, so this system of device power switching needs to be automated. Fortunately, there is an existing system in place for that. Under the driver’s seat is the famous X145 terminal. A diagram from the Sprinter EK1 manual is included (left) showing the location under the drivers seat and also an explanation of each terminal on the connector. I chose to connect to the “Power with engine running” terminal, as I decided I only needed my amp and subs turned on when the van was running (and thus the alternator running too). You may choose the ignition power to have it turn on when a key is inserted into the ignition (but may draw down your batteries fast, depending on the size of your installed system). I haven’t had a problem with my setup as I don’t tend to sit around in the van with the key in it but the engine not running very often.

To be clear, each audio device (converter, amp, subwoofer) is powered directly from my main fuse panel (where my van lights, usb outlets, 12v ports, etc are also wired) with 8 gauge wires from the BOSS Audio KIT (more on that in a second). But the signal to turn the units on comes from the D+ (terminal 1) terminal under the drivers seat. This just requires a small wire to ‘send’ the signal. I have this main “turn on” signal coming into the LC2 speaker-level converter’s “remote in” port. And then two wires coming out of the LC2’s “remote out” port, one to the amp and the other to the subwoofer. This provides the “turn on” signal to these two additional devices. The LC2 has a system called “GTO” or ‘Great Turn On’ that automatically senses when it receives a signal from the speaker-level input and is supposed to turn it on automagically. This may be true – but I have heard bad stories about these systems popping or turning off intermittently or other bad things – not specifically for the LC2, but once you have read enough bad reviews about automatic turn on systems, going with a failsafe direct turn on connection (especially when Sprinter makes it so easy!) seems like a good idea. So to that end, I have the GTO function turned off. But I’d be curious to hear if others have had good experience with it.

Below is a wiring diagram for the power to each unit and the “remote turn on” wire (shown in pink).

For the large gauge wiring that is needed to power an amp I chose the BOSS Audio KIT. I used two of these, on for my subwoofer and one for my amp. This gave me all the wiring parts I needed for both systems, plus a few extras (I didn’t use the fuses it came with because I just went direct to my main fuse box). The cables and wires in this system are okay. I don’t actually believe that it is 8 gauge, but it gets the job done and I have felt the wires when the system is running pretty hard and they don’t appear to be heating up in any detrimental way – so that is promising. I am sure you could spend more money on a better wiring kit, but for me, this worked pretty well.

I spent quite some time choosing an amp. There are just so many options and things to choose from. In the end I went with the Rockford R300X4 Prime 4-Channel Amplifier. It had all the functionality I wanted/needed and has been fantastic. It was easy to install and sounds really good. The biggest feature I wanted (in addition to wanting something around 300 watts) was the ability to take 1-channel stereo input (the left and right signal from the LC2’s main output) and direct it to the 4 amplifier mono channels. The R300x4 has a switch that does just that. You can provide it 2 or 4 mono channels and either distribute or combine them. So i have mine set to 2-channel mode and it works just how I want. Other amps might also have this functionality, but it was difficult to determine that from my research. Ultimately, I am quite happy with my purchase.

3. Rear Speakers

Not much I can say that is particularly interesting about the rear speakers. I built the mounts for the rear speakers into my wheel well boxes so they don’t take up any additional room (that wasn’t already being used) in the van. Then it was just a matter of running wire through the walls and across (under) the floor to the speaker locations. I suppose I could have gone overhead, but going under the floor boards seemed pretty straightforward anyway (I had a slight gap between the laminate flooring up front and the rubber flooring in the back that served as a perfect wire channel).

For speakers, I matched my JBL front speakers with JBL GTO938 6×9″ Coaxial Speakers. These were the right size and had the correct power handling for my amp. They sound good.

That about covers that….

4. Subwoofer

Lastly, installing the subwoofer. I went with the BOSS Audio BASS1400 1400 Watt Low Profile Amplified 10 Inch Subwoofer. Again fairly straightforward install. Run the RCA cables from the LC2 to the subwoofer and connect it to power and the turn on signal and away you go. I know everything in this post has been sunshine and roses about the products I have purchased – well that can stop now. I think the subwoofer I bought is not very good. On some music it sounds fantastic, but on others it sounds terrible – rattling and crackling and in general being no good. But it was cheap! Lesson learned, you cannot get “1400 watts” (yeah right) for $120. I think something from Rockford, Alpine, Kenwood, or Pioneer with much less (claimed) power and a little bit higher cost would have been much better. But that is something to dream about for the future. If folks have suggestions, I am all ears.

Conclusions

That covers my radio / stereo system recommendations for the Sprinter van upgrade. Overall I am very happy with the sound system. It is definitely a huge improvement to the overall sound in the van and the general road trip experience. The stock head unit continues to perform very well with the upgraded systems behind it. I appreciate still having the stock feel, not having to worry about integration with the steering wheel controls, or being more attractive for theft. And yet there isn’t really anything I would want out of a new head unit that I don’t already have with my phone (mounted to the drivers side vent).

With good music, we can drive all day and through the night (if the destination is worth it). Hope this helps, feel free to ask questions or provide comments below.

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