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'17 Fiesta ST - A-pillars, Illusion Audio front stage, JL Audio amplification and DSP

25K views 73 replies 16 participants last post by  Prickles 
#1 · (Edited)
So, after getting back into car audio earlier this year with my MK7 Golf R build, I decided my '17 Ford Fiesta ST needed an upgrade as well. Car is lightly modified with a Cobb Accessport, Boomba short throw shifter, GT500 shift knob, GarageLine accelerator pedal mount and Sparco wheels.
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I started off by choosing a front stage that would allow mounting the mids/tweets relatively on-axis, and the Illusion Audio C3CX's fit that bill nicely. These were paired with the Illusion C6 mids that serve as midbass drivers in this fully active 3 way front stage.

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#45 ·
Decided to upgrade my sub to a JL Audio 10TW3. The Dayton sub has a sealed enclosure F3 of 63hz, so it struggled to go low enough to round out the bottom end (the JL has a sealed F3 of 40hz). I've found the JL response to be a lot flatter as well, requiring only a few bands of minimal EQ while the Dayton needed 7 bands with significant adjustments.
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The JL is equally shallow on the back end as the Dayton, but significantly taller on the outside of the enclosure (particularly with the tall JL grill). So, I re-engineered the top portion of the enclosure to allow the JL to sit lower and more flush.

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Added an Audiocontrol LC2i I had laying around for high-to-low signal conversion, as I'm not sure running the speaker-level factory outputs directly to the TWK-88 RCA inputs was the best route to go. There IS less background static now, but not sure I can detect any other improvements. Will add pics of that addition soon.
 
#47 ·
Decided to change both power and ground distribution blocks. Liked the size of the previous KnuKonceptz blocks, but while they DID take 1/0 AWG in and 4 AWG out, the connections were too small to accept wire ferrules with either. The connections also tighten from the SIDE, which made it very difficult to be serviceable in such tight quarters. The slightly larger KnuKonceptz power block that replaces the smaller version tightens at an angle from the top and accepts wire ferrules. In order to route the wiring to accommodate the larger power block, I needed a ground block that would allow a higher connection point so 1 ground wire could run on top (and 1 that also tightens from above), and this InstallGear piece ticks all the boxes.
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#49 ·
A few observations on the system design, tuning and the like: I initially bridged the XD400/4 to provide 200 watts to each Illusion Audio C6, but I was getting some harsh bass notes occasionally that almost sounded like bottoming-out, primarily on the left side. Concerned they were getting too much power (although the gains were at minimum), I decided to just run 2 channels at 85 watts to each midbass. Surprisingly, I actually got an identical response (with gains optimized on 0 db tones), so the problem was either the physical properties of the door or something odd in the factory system. The interior door skin is plastic instead of sheet metal, so the lack of rigidity may be causing the problem. I deadened it as much as possible, but the problem remained. I decided to continue powering the C6's with the 85 watts since I'm getting plenty of output, and I've been able to tame the problem with EQ and raising the crossover to 75hz at 24db L/R.

I previously complained about the Ford head unit's audio performance, but it improved a bit with the LC2i providing high/low conversion. It still lacks some resolution, particularly on more complicated musical passages, but it's livable. The Fiio M11 is obviously much better, but I've found it difficult to use while driving, which to me defeats the purpose. I'd rather have the convenience, functionality and added safety of using the factory system and lose the resolution of the M11.

TWK-88: easy to use, does the job. Wish it had speaker-level inputs and signal sensing. Also would like maybe 14-15 bands of parametric EQ per channel instead of 10. 10 bands for each speaker in an all-active system sounds sufficient, but a few more bands would still be handy. I wanted to go all JL for amplification/processing, but if I was starting over, I'd go Helix or Zapco for the DSP. That said, I've been able to get it tuned really well. It's just taken some time to get there.

Illusion Audio C3CX's: In my particular application, with a-pillars and nearly on-axis mounting, the imaging is unreal. Still wish they came with some cool factory grills, though....

Weather's been bad lately, but hope to get the ST cleaned up for some final install pics soon and then call this project done!
 
#50 ·
Added a back-up camera this weekend, using the FORscan program to activate the option in the Ford Sync system. Neglected to take pics during the actual camera install and routing the wires through the hatch (a HUGE PITA). Once I got the wiring to the interior, it was secured to the factory wiring harnesses with zip ties all the way through the car to the head unit/monitor.
Electronics Multimedia Technology Electronic device Vehicle

When not equipped with the camera from the factory, the video input pins in the harness plug to the monitor are unused, so I took a couple harness pins from an old head unit harness I had laying around and placed those in the correct pin locations (center of the video connector to pin 14, shield/ground to pin 15). After taping and zip ties, the install looks OEM.
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#51 · (Edited)
Removed the Audiocontrol LC2i, as that addition led to some alternator noise. Obviously a ground loop, so I could have worked to de-bug the situation, but instead I experimented and got really picky with the input levels directly into the TWK-88 and ended up with a cleaner signal. From there it just made more sense to remove the LC2i.
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I had been undecided on doing a thorough sound deadening job on the Fiesta, but after using it as my daily driver for the last few months, it's apparent that it definitely needs some deadening, particularly in the area of road noise and vibration. So, while I was routing the reverse camera wiring, I went ahead and took out the passenger seat and applied NVX deadener over the floorboard and inside some of the trim panels. Will try to duplicate that effort on the driver's side in the next weekend or two.
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#56 ·
Had time this weekend to apply a good amount of CLD to the driver's side.
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Also spent quite a bit of time tuning and came across an odd challenge/situation: I had to use different crossover slopes for each midbass. The frequency response works out fine on the left side with all 12 db slopes, but the right side develops a huge hole in the F/R from cancellations. So, in order to alter the phase slightly and eliminate the cancellation, I used a 24db low pass to the right midbass and... Poof! The big F/R hole was gone. But it only worked on the right side. If I tried changing the left side to match, that side developed the F/R hole (I was tuning the front stage, so no sub-bass extension :giggle: ). Shifting the phase 180 degrees and keeping the crossovers consistent from side-to-side wouldn't work, either.
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#57 ·
To follow up on my last post regarding tuning, F/R and phase issues, I've found that issues with very small dips/peaks on individual speaker measurements can be magnified when combined with speaker pairs/sets. I was able to smooth out the response by adding a bit more EQ to the individual driver dips while returning all the crossovers to 24db slopes. I didn't encounter similar issues in my MK7 Golf R installation/tuning, so not sure if it's a function of the Fiesta interior, the drivers themselves, or the differences between DSP's. The TWK-88 does seem to measure with steeper roll-off on 24db slopes than the Zapco Z8-IV II, though that may be a function of the car interior as well. Anyway, the tune is really nice now and it brings a big smile to my face every time I fire it up. :D
 
#58 ·
Rebuilt subwoofer enclosure. When I installed the JL 10TW3, I found the exterior mounted portion was taller than the Dayton model I used previously. To compensate, I added an extra 1/2" top portion to flush it a bit better. Unfortunately, this also caused the bottom of the enclosure to come in contact with the spare tire when raising/lowering the assembly. The rebuilt enclosure is wider and longer, allowing me to flush the woofer an extra 1/2" while gaining a 1/2" bottom clearance and maintaining the same interior volume (app. .52 net cu. ft.). This will also allow me to add a cover to completely hide the sub and protect it while hauling stuff in the hatch area.
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Covered the top of the sub enclosure in black carpet rather than vinyl this time. Didn't like the look of the vinyl on the last version.
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#59 ·
Added cleats to the bottom of the floor so the assembly will correctly locate itself when lowering it.
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So, yeah, it looks almost identical to before, but it functions significantly better when raising/lowering the floor to access the spare or the amplifiers. Maintaining as close to full functionality as possible is one of my design goals, so I think the effort was worthwhile.
 
#60 ·
I haven't been completely happy with the grill cloth upholstery on my a-pillars. Although it's not intrusive and blends in OK, I just prefer the look of vinyl. A previous attempt at wrapping one of the a-pillars in vinyl was unsuccessful; the shape is just too severe. So, I procured another set of salvage a-pillars and commenced upon version 2.0. :)

The goal this time was to smooth out some of the more severe edges and angles and to change the speaker aiming from almost fully on-axis to a somewhat off-axis orientation. Speaker rings were constructed from ABS plastic this time instead of MDF (I failed to take pics of the ring construction...).

Initial wrap (used an old t-shirt that was really stretchy):
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This time around, instead of creating a scallop "bed", I simply cut out the shapes and stretched the cloth fairly tight to get a flatter bed.

First layer of resin:
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After a number of hours applying Rage Gold and sanding everything smooth.
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#62 ·
Driver's side pillar from the driving position:
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My grill work turned out cleaner this time as well:
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The new pillars are a noticeable step up in fit-and-finish from the first version, and the vinyl integrates into the interior much better than the grill cloth.
 
#66 · (Edited)
Thanks for the compliments! Much appreciated.

Definitely needs re-tuning! I frankly was surprised at not only the amount of adjustment required, but the nature of the changes in frequency response. I've only had time enough to adjust the existing tune to smooth things out, but I'll probably do a full re-tune. I actually think the frequency response is smoother in the more off-axis aiming. I'll try to confirm that theory with some raw measurements this weekend.
 
#73 ·
Thanks! I used DAP Weldwood Landau Top and Trim. Really indispensable for this type of upholstery work. The 2 game-changers for me on the vinyl upholstery were learning to be way more liberal with heating the material to achieve the necessary stretching, and buying a gravity-feed sprayer to apply the adhesive. 😊 (y)
 
#74 ·
Hey mate, were the A pillars easy to remove? I really want to go a 3-way front stage in my 2015 ST but wanted to get an idea of the work required. Currently running 2 way +sub in factory locations (Helix M SIX DSP and M ONE X, plus a T'EYES CC3 head unit).

Appreciate the time and effort put into this thread.
 
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