Complete Fender System Speaker Upgrade *Updated Nov 22/19*

[IK/GTI]

While the Fender System is fairly good for an OEM system, it is still somewhat lacking compared to other systems I have built. I therefore started to look at what could be done to make it better. My goal was to spend as little time and money as possible, and not upgrade the Head Unit or Amp. I was not able to find much complete info on anyone doing this upgrade (of all the speakers), so will try to provide this here. While this is not a how-to post, what will be covered are some of the issues/challenges (pics provided) that I found throughout the install.


Stage 1 - Subwoofer

A quick search on this forum and others indicated to me that the OEM Sub is the weakest link in the Fender system. This is where I started, replacing the OEM box with a 10” Fosgate R2 (low profile) Dual Voice Coil Sub in a custom enclosure. This is pretty straight forward and the parts required are readily available online (including the required part numbers).

My goal was to use the smallest box possible to maximize the available space under the trunk deck for emergency equipment and gear that I normally store. I wanted to keep the jack in stock location and keep the spare. I could have used the 12” version, but this increased the box size and I was not looking for any major bass upgrade, just the minimum improvement upon the 6” version. There is also a 10” P3S version, which can handle more power (and costs more), but I was not planning on adding an amp. As well, one could use the 8” version, but the space/cost savings would not have been that significant. The 10” R|2 seemed just right for me.

I used ½” Birch Ply to minimize the overall depth but had to add additional supports inside the rim to increase the box’s rigidity.

This worked out well and I used poly fill inside the enclosure (about 8 oz). I did not add terminal connectors on the outside, and instead just passed the wires through the box. Seemed redundant to have a quick disconnect, when I was going to use the stock OEM connector. I was not planning to take this in and out a lot.

Because I reduced the size of the box, it would sit squarely on the spare tire. I was concerned having a box with a down firing Sub, sealing around the spare tire and not allowing enough air to flow. So, I added stand off’s to keep the box off the tire. To keep the box from shifting, I added posts that would grab the sides of the tire.

I was also concerned the plastic spare wheel lock down nut sat too high in the wheelwell and might interfere with the throw of the speaker. Therefore, I reduced it’s overall height by a couple inches.

While I likely over engineered the box, it ended up very ridged and I had the tools to be able to do the work. I also just used a rattle can to paint rather than fabric wrap the box. This reduced the overall size slightly and cost of labour for me. Here is the final position in the trunk.

The final outside dimensions were 23 3/8" W x 21” H x 4” D, unfortunately this did not work out from one 2' x 4' sheet of ply but I had some extra material left over from another project. Though I did not weigh it, I estimate it is 22 to 25 Lbs. After this upgrade, I dropped the Sub setting on the head unit from +2 to -1, as there was significantly more bass.

VERDICT: Recommend this upgrade 110%. At around $200 CND cost, this made a noticeable difference in the system sound. I can feel the Sub through the seat now and the bass is sufficient for my needs. If you want to just do the minimum work to get the best sound out of the OEM Fender System, this is all you will really need IMO.


UP NEXT: Stage 2 - Door/Pillar speakers

 

[IK/GTI]

Replacing Door/Pillar Speakers

For a while now I have wanted to upgrade the door and “A” pillar speakers in my MK7.5 GTI as I had a set left over from my last vehicle. I was hesitant because the Fender System uses 2 ohm speakers and mine were rated 4 ohms. I also had high end passive crossovers that I wanted to use. Through my research, it looked like the 4 ohm speakers would not be an issue but the 2 ohm source would cause issues with the crossover points on my 4 ohm crossovers.

This was not ideal for me as I felt the only options left were to replace the existing speakers with my set (no crossovers) or get a new set of 2 ohm Midwoofers and Tweeters (and possibly crossovers). There were options for the Midwoffer speakers but not as much for the 2 ohm Tweeters at a high quality level (or reasonable price). As I wanted to reuse my existing speakers and save some money, new speakers ended up not being an option for me.

The other issue was the front door speakers are dual voice coils, and I could not find any 6.5” 2 ohm DVC Midwoofer speakers that would fit (though I did not search too hard). Rather than do too much research, I just decided to open up the doors and try my existing speakers to ensure they at least worked. A quick test showed that they did but produced a slightly lesser volume at the same setting, but cleaner sound. Here are the speakers I used, all are 4 Ohm and 91 - 92 db efficiency -

“A” Pillar – CDT 1.1” Silk dome Tweeter TW-26
Front Midwoofer – CDT HD-6
Rear Tweeters - CDT ¾” silk dome tweeters, DRT-20
Rear Midwoofer – CDT EU-6NEO


Rear Doors

The OEM speakers are actually 5.5” (nominal) and my speakers were 6.5” (nominal). I manufactured my own spacers out of two pieces of 5/8” thick particle board and epoxy coating them for water proofing. I made the ring 7” in dia. and 1.25” high. With the speakers attached, the overall height was 1.375”, which was less than the 1.650” height of the OEM spacers.

There were two issues with my sizing. First the diameter should have only been 6.750” max. As there was a slight interference with one of the inner Door Panel mounting plugs. I had to shave material off of the spacer and the Door Panel in one location to close the cover. The second was that the height required me to trim the ribs around the speaker opening on the inner Door Panel, to close the panel. I shaved the inner and outer rings to below the height of the centre ring to make it close up.

I originally wanted as much height on the speaker mount because most cars I have worked on had an interference with +2.5” deep speakers with the window glass rolled down in the front. There seems to be lots of space in the GTI doors, so I could have reduced the height of the spacers by almost 0.500” and still missed the window (forgot to take the actual max. depth measurement). Having the mount higher and larger gave me a very rigid mount which has likely helped the rigidity of the door mounting area. One thing I liked about the door frame was that the metal around the speaker opening had a 0.125” high, 90 degree, folded edge (to the inside of the door), instead of just a hole cut in the metal. This gave some additional rigidity to the sheet metal of the door frame. I also added a bit of dampening material around the opening.

For the Midwoofer speaker wiring, the polarity is marked on the speaker housing at the terminal -

Here is the finished door with Midwoofer installed -

For the tweeter replacement, the OEM position worked out easily for me. To remove the tweeter, you just need to grind the little stub off of the 3 mounting posts and pull the tweeter off -

My replacement tweeters came with a housing that I was able to notch in three places and then epoxy the whole unit in place

For the polarity, this was harder as the tweeters only note they were 2 ohms but had no polarity markings. They also had two white input leads that did not differentiate them from each other. Doing a battery test, I decided these were the Pos & Neg terminals

Couldn’t be sure as the tweeters don’t move much but it seem to work out in the end.


Front Doors

The fronts were very much like the rears, but no tweeters. I used the same size particle board spacers which did not need trimming. These HD-6 speakers were a little larger at 6.75” Dia. Only part of the inner door cover and the rings around the speaker opening, needed trimming.

On all the Midwoofer speakers, I added a bit of silicon between the door frame and particle board spacers and added some electrical tape between the mount and speaker as a gasket. This was because I had read that there is a possible issue with water getting through the rear speaker opening and pooling on the car floor causing mold issues with the Golf’s. This was why I epoxy coated the spacers, so they would not absorb water.

For polarity, this was marked on the speaker Terminal area as well.. I used just one of the two available input wire sets, they pair up as Red for positive and Brown for Negative. Not sure if it matters but I used wire #1 and #3, from each side.

“A” Pillars

The covers are hard to get off but not impossible. I almost didn’t replace these Tweeters but decided it was better to go fully 4 ohm inside the car since I had the parts available. Here is a How-To for removing the “A” Pillar covers

https://www.autoinstruct.com.au/manufacturer/volkswagen/mk7-golf/mk7-golf-a-pillar-trim-removal/

The removal just requires a bit of force. You need to pull the plastic Pillar cover out of the small triangle window moulding section before it will come out. The Tweeters are held down on three posts like the rear Tweeters, just grind off the top heat staked bumps. For Polarity I just followed the wire colours of the door Midwoofers. To attach the Tweeters I again just used epoxy to mount them. The dimensions of my new Tweeter is about 1.25” dia. x 0.750” H and had no interference issues when reinstalled on the car.

Reinstalling the Pillar cover back on the car was fairly easy. Just needed to make sure to get the edge of the cover into the frame of the triangular window moulding first (#1), then tuck in the other two tabs to get around the dash (#2). It then slipped into place easily.

The only part that gave me issues was the top metal retaining clip of the three that are used. After popping out the “A” Pillar Cover, the top two clips have retainers that keep the cover in place (I assume this is so that when the air bag goes off, the cover does not fly into the cabin). You then need to slide the top two clips out of the cover (there are slots in the car frame), to remove this piece. On the top clip, there was a moulded plastic stud that made it difficult to get in and do this with my screwdriver. If you use a thinner, flat bar of some kind, it should be easier to get in to access, and slid out the clip

VERDICT: This did improve the sound further and coupled with the Sub upgrade makes the system sound better. The base and highs are now much tighter. There was a distortion at higher volumes that I thought was just my ears getting older, but after installation this was gone. I can crank the volume past the ¾ point with no distortion; this system can play really loud now. The CDT speakers I had seemed well matched for the amp, they sound better than they did when I had then with a 25 Watt RMS Pioneer Head unit without a separate amp...

The CDT speakers are the low end of the higher quality market but seem better then the Fender OEM speakers. If you have just a low end set lying around that you want to drop in, you may not get much of an improvement. Not sure if it was the fact these are 4 ohm, larger diameter, better mounting conditions, but the overall affect for me was positive. Here are pics of the OEM speakers (front, rear, and pillar). I noted the front Midwoofers have much larger magnets than the rears and the “A” Pillar Tweeters are bigger than the Rear Door Tweeters (and have different part numbers). There were no identifying marks on the Midwoofers..I also could not find any kind of crossover on the Midwoofers, the terminals seem to go directly to the wires leading into the magnets/cone area.

UP NEXT – Limitations/Conclusions

 

[IK/GTI]

Limitations/Conclusions

While now sounding better, this is far from ideal. The limitation to this set-up now is the Head Unit. Its lack of advanced control functions is a problem. Being limited to just 3 bands of equalization and a Sub control, a 7 band equalizer would likely have been a better choice for a premium system. Having no control of the various source outputs to balance them, is a slight issue now as the difference seems more acute. They (Fender) also seem to have customized the crossover points and wattage for the OEM fronts, rears and pillar speakers.

The CDT HD-6 fronts are rated 55 Hz at the bottom end and can pump out more base, which is not bad but not ideal either. Without being able to adjust the sound further, these speakers in the front doors are a little harsh..

The rears are somewhat anemic. They are nowhere near as loud as the fronts, but since these are just fill, they do the job. I did have to increase the bias to the rear a little more to get the sound I wanted. Just for reference, my setup numbers before this upgrade were -1, +3, +2, +1 of equalization. Currently I have it set to -4, 0, -2, +1.

For the pillar Tweeters these seem set more for Midtweeter frequency ranges. There is a fair bit of vocal frequencies produced through these speakers. I would like to know what actual frequencies are being relayed through all the outputs as they seem odd. Without equipment to measure anything, these are just my guesses only.

Vocals are a bit harsh on different songs in the front speakers. The equalization is not up to the task of shaping the sound to my tastes at the high end either, and this is where more equalization bands might help. The other problem is with the fact there is too much distance from the front Midwoofers and the pillar Tweeters (I thought this was also a problem with the OEM set up). For me this gives a weird soundscape from what I would like to hear.

Not sure if only using one of the 2 ohm inputs on the front speakers is going to cause any issues with the amp down the road, or mix and matching the 2 ohm Sub with the 4 ohm interior speakers will be a problem. If anyone can comment on this, I would like to hear from you.

In conclusion, for me this was a satisfactory upgrade but not sure if I would do this if I did not already have the speakers on hand (did I mention I can really crank up the volume with little to no distortion … lol). Going out and spending $500 - $700 (CND) on door speakers may have made me think twice about doing this. For me, having the parts and being able to do the work myself, made this a viable option and worth my time and efforts YMMV.

SUPLEMENTAL: Stage 3 would likely be looking into further upgrading the system with Amps and/or Equalizers; it seemed out of the scope of what I was trying to accomplish at this time. Re-routing all the wiring and tearing up the interior seemed too much work and the Fiber Optic output from the HU would be an issue for me. I think I would rather spend this time/money on a Downpipe next. Therefore for me, this did not seem a good upgrade to pursue to this time; I was pleased with what I achieved out of just upgrading the speakers. If in the future, I find the extra money or time, I may reconsider this as there is still some improvement needed.

 

[IK/GTI]

UPDATE: Nov. 22/19

Still think there is some more improvement to be made to this setup and I therefore have tried to address some of the limitations in two ways.

First, there was the issue of not knowing what frequencies were being produced through the various Amp speaker outputs. I came up with an idea to get a ball park understanding of the Fender system. On my CDT Crossover (CO), I know they cross over at around 3500 Hz for the Tweeter and the upstage Tweeter at 8000 Hz. I hooked this up to the various inputs for the doors and pillar speakers and attached speakers to the CO outputs to hear what sounds were produced. Though I could not tell the exact frequencies, here is what I found –

1) The Front door Midwoofers seem to be receiving a full frequency range. I checked again to see if the Fender speakers had a built in CO, but I still could not identify any added components

2) For the rear door Midwoofers, it was the same as the fronts, a full range of frequencies.

3) For the Rear and Pillar Tweeters, these got the higher frequencies only. With the Midwoofer attached there was no mid to lower sounds produced.

While not conclusive, I feel the Midwoofers in the doors where getting a full range of frequencies from the amp, which is not ideal. To see if I could adjust the sound, I had an extra set of Midwoofers (CDT CL-6, which can center mount Tweeters) and an extra set of Tweeters (CDT CD-20) and replaced the HD-6 in the front doors. I then added a 2-way crossover to filter the signal.

The CO point might not be idea but this seemed to take some of the harshness that I had complained about originally on the front doors. Not sure if this is due to the new Midwoofer/Tweeter combo or the addition of the CO. For the rears I have not changed anything yet. I did try these with both the Tweeter and Midwoofer attached to a CO, but I’m undecided whether this sounded better over the original set up with the speakers just attached to the Fender outputs. I will need to review this some more.

There is enough room for a fairly deep Midwoofer in the doors but there is little room for a CO mounted on the door itself. I only found one spot that would work, and only because this CO is small. There is a second spot under the arm rest of the door panel that can fit a slightly larger CO, just more difficult to mount. Here is the picture of the final setup.

The second issue I tackled was the fact the Pillar tweeters were too loud in relation to the rest of the setup and have no separate way to adjust them. I purchased a CDT LP-1 Attenuator to adjust the volume of these speakers. This has a single control knob for both sides and worked out perfectly. While you don’t have enough equalization bands with the Fender system, this balanced out the sound better with the front doors Midwoofers and really helped balance the sound within the car. I have now adjusted my settings to the following -5, -2, -1, 0, seems a better setup for all sources and songs with the door speaker replacement above. I also was able to move the bias from front to rear closer to the front with this setup. Looks like I have reduced the front Pillar Tweeters by about 4 – 5 db.


CONCLUSIONS:

I will likely do nothing further to this setup other than maybe add a 2-way crossover to the rear door Midwoofers to filter out the higher frequencies. Here are my recommendations if you are thinking of just upgrading the speakers on the Fender system

1) Do the Sub upgrade, well worth the money and time. Get an attenuator for the front “A” Pillar speakers to adjust the volume. Even with the stock speakers this will balance out the system and compensate for the lack of more equalization bands. These two adjustments together will significantly improve the soundstage within the car and cost the least amount of money.

2) If you have a set of good speakers lying around, then this full upgrade may make more sense. Not sure I would have done this is I had to buy the speakers.

3) If you are going to replace the speakers, 4 ohm parts seem to work out well. For the front door I would recommend using coaxial speakers. For the rears it is not necessary.

4) Upgrading these speakers did reduce the distortion I had with the Fender system. I am able to get really loud now with this upgrade. On the OEM Fender setup I could not go above ½ volume, I can now go past ¾ with no issues. The sound is now tighter and cleaner. Overall a good upgrade for me without having to replace the Head Unit or Amp. I do not have the advanced knowledge to determine if using higher quality 2 ohm speakers may also give the same results.

 

[zech912]

Interesting write-up. I have to believe those silk tweeters would sound good. I have the Morel Piccolo (which are silk) in my other car and they absolutely wonderful. I am surprised the tweeters are only 2 ohm, usually tweeters for some reason are higher ohm, not lower. I believe you would be happier with 2 ohm woofers, especially the Focal. Finally, I believe you would have been happier with the CDT FM-007 mounts. they are made for VW GTI, perfect fitment, require no carving, and a solid foundation does make a difference in sound. in any case, great write-up.

 

[nype]

Nice work!

So how much will you want to make me a box?

 

[IK/GTI]

Interesting write-up. I have to believe those silk tweeters would sound good. I have the Morel Piccolo (which are silk) in my other car and they absolutely wonderful. I am surprised the tweeters are only 2 ohm, usually tweeters for some reason are higher ohm, not lower. I believe you would be happier with 2 ohm woofers, especially the Focal. Finally, I believe you would have been happier with the CDT FM-007 mounts. they are made for VW GTI, perfect fitment, require no carving, and a solid foundation does make a difference in sound. in any case, great write-up.

The tweeters sound great, no issues there, I think it is how the amp is set. Normally I would expect the Tweeters to cross at around 3500 - 4000 Hz, the pillar and rear door Tweeters seem to be crossed much lower than I expected. If I remember correctly, though noted as 2 ohms, when I measured them they were actually 3 ohm. My CDT’s measured 4 ohms.

I likely may have been more happy with the 2 ohm Midwoofer if money was not an issue. As for the mounts, same thing. The CDT would be great, other than the price, $72 USD for a pair on Amazon. I only had to pay $35 CND for the epoxy and my time.

Maybe not clear in my post, though I think there is room for improvement, the CDT speakers are noticeably better than the OEM Fender speakers.

 

[IK/GTI]

Nice work!

So how much will you want to make me a box?

Haha ... likely more than it’s worth.

 

[nype]

Haha ... likely more than it’s worth.

Especially with shipping. I had to ask.

 

[StealthGTI]

Nicely done!

 

[riceburner]

awesome information.

 

[IK/GTI]

Updated Nov 22/19

 

[Sc629]

I know that you can go into amp module on coding and there's and adaption that lets you mess with the low, mid, and tweeter frequency. I wonder if that is what controls what signal ranges come from which speaker set?

Also, it is possible to code the 5f module sound system to "external amp" (options are stock, fender, and external) but am not sure what it entails.

 

[IK/GTI]

Thanks for the info, This might help further improve the sound. I'll have to get someone with an OBD11 to verify.

 

[skadee]

Nice work! It looked like you said you used the original wiring harness on the sub (I'm planning to just do the sub), but how did you get the wiring off of the original sub and what's the wiring polarity of the harness for each coil? I'd prefer to keep the OEM sub in a condition that I can plug it back in.

And do you have the dimensions of placement for the 4 posts you used to hold the box to the tire? I can always trial and error that, but if you know the dim's, that'd help.

Did you just make the stand-offs out of wood?