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469 Posts
Discussion Starter #1 (Edited)

I first joined Diyma back in January after spending countless hours failing to diagnose my engine noise in one of my first installs. Car audio was just a small hobby of mine, and all I wanted was for my car to sound a little bit nicer. I was apprehensive about making an account and posting for the first time, but the feedback I received really helped me out and got me started on the path that I'm on today. I'm still learning everyday from the wealth of information on diyma and try to contribute as much as I can in return.

Around May I decided to change careers and pursue car audio. I had the amazing opportunity to apprentice at the best car audio shop in my city (Musicar Northwest) for about 2 months over the summer. I learned something new every day from the informative, helpful, and extremely skilled mentors there. Unfortunately, I was struggling to be productive for the company, given my lack of experience, so I was eventually let go of. Nevertheless, being exposed to such a high level early on has set the standard that I will strive to reach one day.

Here is my build log thread, which is the culmination of what I've learned from Diyma and Musicar over the past several months. All the work shown here was done in my driveway. This build log would be twice as long if I included all the failing/experimentation that I did. I've only used a router once or twice before this so I was learning as I was building. All pics were taken with my Galaxy S7 and Note 9. Hope you guys enjoy and feel free to ask me anything in the comments or PM me.

Build is in a 2015 Kia Optima Hybrid:

Total Build Time: Approximately 300-400 hours

Table of Contents
1) Equipment list
2) iPad Pro integration
3) Door modification and Midrange/Tweeter mounting
4) Grill cover fabrication
5) Passenger Footwell Subwoofer Enclosure
6) Helix Director Mounting
7) Overall system picture
8) Things that don't have pictures
9) Tuning and Measurements
10) Subjective review
11) Future Plans

1) Equipment list
Source unit = iPad Pro 12.9". Mainly using Spotify and some 24bit FLAC in VLC Media Player
Processor = Helix DSP Pro MKII with Helix Director Remote
Midrange and Midbass Amp = Alpine PDX-F6 (150W RMS x 4)
Tweeter and Rear Amp = Alpine PDX-F4 (100W RMS x 4)
Subwoofer Amp = Alpine PDX-M6 (600W RMS x 1)
Tweeters = Audiofrog GB10
Midrange = Audiofrog GB25
Midbass = Audiofrog GB60
Rears = Audiofrog GS62 coaxial
Subwoofer = Audiofrog GB10D4

2) iPad Pro Integration

Factory radio and climate controls:

This was my first attempt at mounting the iPad. This was a simple floating mount with magnets. I ran with this style for many months until I decided to integrate the iPad into the dash itself. Let the cutting begin!

I pulled out the climate controls and factory radio, then cut the rectangular opening just large enough to overlap the iPad. Body filler was used to bridge the empty space between the dash and the iPad. Unfortunately, I began cutting up my dash before I ever had the idea to start a build log, so the only picture I had was the end result of attempt number 2:

I moved the climate controls into my center console storage tray. This involved me lengthening the wiring harness through the center console. This took 160 ft of primary wire and 82 solder joints. Thankfully it worked perfectly and helped me learn how each wire communicates with the climate control brain in the car.

My second attempt at mounting was an improvement, but I was still looking for more of a factory fit and finish. I decided to expand the opening slightly and realign the edges to be parallel with the iPad screen. I then began fabricating a trim bezel, starting with thinly routed strips of 1/8 inch acrylic:

I taped off the iPad and secured the acrylic in place:

I bridged the gap between the face of the iPad and the dash with Rage Gold body filler:

Testing fitment:

I then heat bent additional strips of acrylic to match the curves of the unevenly shaped dash and secured them in place. This was one of the main reasons I chose to use acrylic over MDF (it is also much less prone to snapping in half when thin):

Filled the gap again:

Used a piece of 0.22inch acrylic as the bottom wall to close off the rectangular frame into shape:

Time to finish and SAND for a hours on end:

Wrapping the side panel pieces in factory matching leather vinyl:

Rough test fit:

Taped off the bottom edge to fill in the large gap:

Smoothed, sanded, and painted the filler piece. Now there is a flat surface for the bezel to rest on:

After hours of sanding and finishing, the final product:

The steering wheel controls were integrated into the iPad by programming different resistance values as keystrokes on a USB keyboard module. The module was connected to the iPad using the USB Camera Connector kit from Apple. This gave me volume up/down, Track forward/back, Play/Pause, Mute, and Home button. This also allowed me to use the Helix HEC USB addon and connect my iPad directly to my Helix DSP via USB.

Here I cleaned up the wiring behind the iPad, wrapping most wires in TESA cloth tape and hiding them away:

Looks like there's TONS of room for a sealed enclosure for a dedicated 6.5in midbass driver in the future when I experiment with center channel upmixing/surround. Measures about 15in x 8in x 8in. Not having a double din radio or climate control module really frees up the space in there.

More in the next post.

469 Posts
Discussion Starter #2
3) Door modification and Tweeter/Midrange mounting

Previously, I made custom midrange pods in the sail panel, and tweeters in separate housings parallel to the window. While I was content with the build quality, the acoustical performance of this install was quite literally, screaming for change. There was a harsh reflection off of the driver's side window that drilled into my left ear. I couldn't hear the reflection anymore after moving my head 2 inches over, so I knew it was a problem with the physical location of the midrange. No matter what I tried, I couldn't EQ the shrill sound out, so I had no choice but to move the drivers. The tweeters, also being almost 90 degrees off axis, rolled off too much around 12k+. Pics of my previous build:

While planning my new mounting locations, I aimed to minimize reflections off the windows, windshield, and dash. Another goal was to achieve a wider stage, which meant physically moving the drivers wider. What I came up with was feasible, but demanded some serious modification of my door panel and inner door skin.
Stock door panel:

I wanted to mount my drivers high on my door panels, just under the window so that there is virtually no reflection off the same side window. This also placed the drivers relatively far away from the dash/windshield, minimizing the effect of early reflections compared to dash mounted/a pillar installations. I also tested the acoustics at different locations and came up with these plots. Crossovers and levels were kept constant between the measurements. Blue was the old sail panel measurement and red is the new door panel measurement:

The only problem was, the door handle was directly where I wanted to mount the midrange. This was likely the hardest part of my entire build. I tackled the problem head on, starting with removing off the door handle assembly and making a MDF router template around it:

Door handle removed:

I rough cut a hole for the new door handle location and secured the MDF template in preparation for routing:

I removed my router from the table and freehand routed it with a flush trim bit. Don't mind the frayed fabric, the plastic itself was cut quite clean:

Test fitting door handle

I then made a template for the trim bezel which will hide the frayed fabric and surround the door handle

I aligned the door handle with screws to the inner door skin and test fitted

The levers that operate the opening latch and locking mechanism were just thick pieces of steel wire. I cut off the excess wire length and soldered the wires back together. This part turned out ugly, but it was functional.

Trim piece made of 1/8in acrylic. Acrylic was chosen so that I could heat bend them onto the curvature of the door.

Test fitting

Painted the trim bezel in metallic silver (may change it in the future to flat black)

Permanently secured the trim bezel to the door

Relocation of the door handle was completed and fully functional.

Midrange and Tweeter mounting

A sealed pod made of a 2.5inch PVC end cap was made for the midrange, improving the low end efficiency compared to infinite baffle

In order to recess the midrange pod deep enough into the door panel, I painstakingly cut a hole out of the inner door skin sheet metal, granting me an additional half inch of depth.

GB25 mounted:

The GB10 tweeter was angled almost on axis and secured using weather stripping caulk and dabs of CA glue (survives door slams just fine). I may think of a more secure mounting method with screws later on. As always, quick disconnects were soldered on for easy removal in the future.


469 Posts
Discussion Starter #3
4) Grill Cover Fabrication

The objective of these grills were to protect the midrange/tweeter while also aiding in blending to the design of the door panel. I started with cutting out a rough shape over the opening.

I then created an MDF template for the grill

An inside plug piece was made in preparation for grill mesh shaping

Crushing cage assembled (no hydraulic press here)

I screwed the corners together with an impact driver in order to crush the mesh into shape

I then added a 1/4 inch rabbet to the inner edge of the trim bezel

Test fitting the formed mesh inside the trim

My door panel has a significant curvature to it, so I copied this curvature by filling with body filler

After a heavy sanding session late into the night

Testing fitting the curved grill trim onto the door panel

I flush trimmed these cover pieces made of 1/8in acrylic

What the whole assembly should look like

Taped off the grill mesh

High build primer coat

Followed by a coat of black paint

After applying a special painting technique I picked up from Musicar, which yields a subtly grainy, yet smooth texture:

Peeling the tape off was satisfying

Finished product

Completed door panels with door handle relocation and custom speaker mounting


469 Posts
Discussion Starter #5
5) Passenger Footwell Subwoofer Enclosure

Even though I've achieved up front bass with a trunk mounted subwoofer, I wanted to experiment with something a bit different. The GB10 sub was the perfect choice due to its minimal airspace requirements and great low frequency extension. I had originally done a fiberglass enclosure, but it was built too poorly and eventually ditched. I decided to go another route: Half inch MDF pieces fit like a 3D puzzle.
I began by roughly estimating the sections I would need using cardboard

Once satisfied, I transferred the shapes onto 1/2in MDF

Jigsawed them out

Secured to the footwell with Gorilla tape

I temporarily welded the pieces together with some instant cure spray, dowels, and CA glue, then CAREFULLY pulled the shell out of the footwell

Comparison between my old and new enclosure

Backside of the shell

Mixing some fiberglass reinforced body filler to seal and strengthen the joints between each piece of MDF. I wanted to keep this enclosure 100% fiberglass free just to try something new.

Sealed joints with the filler glass

Smaller pieces of MDF were cut to fill in the large gaps. Then masked off from the inside to prevent the filler from dripping through.

All joints sealed. The enclosure was already rock solid and much heavier than my fiberglass enclosure.

The front face was made of 3/4in MDF

A 1/4in radius roundover was added so that the enclosure would slide in and out easily and not catch sharp corners

Front face attached

Test fitting the enclosure

Used threaded rivnuts to secure the subwoofer in

Front face wrapped and subwoofer wired

Sub mounted. JL Audio 10in generic grill used. I verified that the enclosure was air tight.

I'm pretty happy with how this turned out. The net airspace was approximately 0.6 ft3, per the Audiofrog manual. Dense closed cell foam was placed around the enclosure to reduce vibration transfer. Frequency response measurements will be posted later in the build log.

6) Helix Director mounting

This was one of the first things I did. I simply ran the cable up to the sunglass holder and used double sided velcro tape to hold the director in place. This will be improved upon in the future or relocated lower for easier access. The sunglass holder still functions normally and allows me to hide the director when not in use.

7) Overall system picture

Full shot of the car from the backseat

8) Things that don't have pictures

I have about 80 sq ft of Second Skin Damplifier Pro (CLD) tiles spread out through all 4 doors (outer door skin and door panel), the entire floor, the trunk, and rear deck. I also have Second Skin Luxury Liner Pro along both footwells and the entire floor.
The amplifiers and DSP mounting do not have any pictures for now. They are just stacked on top of each other (PDX series can stack). For now they will remain functional and hidden from sight. My trunk looks 100% factory at the moment.
The GB60 midbass and GS62 coaxials are simply mounted in the factory locations with backwave dampeners and a gasketing material to create an airtight seal.
Changing out the cheapo factory Kia tires to "reduced noise" aftermarket tires provided drastic road noise reduction on par with all the sound treatment (CLD/MLV). Even at highway speeds, I can now maintain an acceptable level of SQ due to the minimized road noise compared to stock. If I had to quantify it: 85% as good compared to parked.

9) Tuning and Measurements

All measurements were taken with a figure 8 pattern at each ear for 30 averages each playing pink noise generated by REW. I exported JBL target curves with Jazzi's tuning companion. Crossover points were 80Hz, 400Hz, and 4000Hz. I then optimized my levels and electronic crossover settings in order to closely match the crossover slopes acoustically. Raw measurements with no EQ applied:

After a round of Auto EQ with REW, and some manual adjustments, I took another measurement of each driver. The Subwoofer and Midbass responded excellently to EQ, unlike the Midrange. You can see some significant peaks and dips between 800 Hz - 3000 Hz.

After a second round of fine tuning, I ended up with these measurements. I used up all 30 parametric EQ bands on my midrange channels in order to achieve these curves. Measuring in 1/48 octave resolution revealed some heavy comb filtering in my midrange, which may be caused by the grill cover partially covering the cone area and causing early reflections. Something to investigate further.
As close to the target as I could possibly get:

Afterwards, I added a +3db shelf filter with a Q of 1 below 160Hz in order to get some more midbass impact. I raised the subwoofer level equally in order to maintain the 80Hz crossover point. I also added in some rear fill on the GS62's. Crossed over at 300 Hz and 3000Hz with 12db/octave Linkwitz filters. Differential rear fill was applied (L-R) and the channels were delayed by about 20ms.
The entire left side was attenuated by 5-6db until the center image was placed center on the dash. I verified my imaging with absolute phase clicks, 31 band pink noise bursts, and the seven snare drum hit track. Everything seemed spot on, so it was time to listen to some music!

10) Subjective Review

After many sessions of tuning, I was most happy with the sound of my current tune. The distance of the center image was perceived to be much further than the physical distance to my speakers. The left side midrange was only 35 inches away from the listening position, but the illusionary center image was at the edge where my dash met the windshield. The snare drum hits in the intro of Rosanna by Toto, Billie Jean by Michael Jackson, and Simple Man by Lynard Skynyrd sounded like the drummer was 20-30 feet away. The natural reverb caused by the recording environment was reproduced very well. I noticed that rear fill will only amplify ambient sounds and room size cues only if they are there to begin with. Flat recordings in studio rooms do not sound any different with rear fill. However, songs with lots of ambient information are significantly "bigger sounding" with rear fill active.

The best way that I can describe the tonality would be: flat and neutral (audiophile-like). Nothing stood out as too bright or too warm. All the fine details in the music were expressed with an accuracy and sound separation that rivals my KEF home audio set. I did add in some extra midbass and sub, but the impact was still tight, clean, and anchored in the center. The subwoofer blended seamlessly with my midbass drivers and provided nice linear output to about 35hz, where it began to audibly roll off, despite what the RTA showed.
Some weak points of the system would be in the 1k to 3k midrange, and also in the 5k+ treble. I will play around with different mounting options in order to address the diffractions/reflections off the grill. Other than that, I'm happy with how it sounds, which is all that really matters in the end.

11) Future Plans

- Add in a sealed midbass enclosure and tweeter (likely GB60 and GB15) as a center channel once the Helix DSP Pro MKIII or Audiofrog DSP are released
- Create a custom beauty panel with edge lit acrylic once I get my amp mounting sorted out
- Move the Helix Director lower, under the iPad for easier access to volume/preset control
- Focus on becoming an actual installer so I can continue learning and improving in a professional setting

If you made it to the end, thank you for reading my long thread! Feel free to ask questions or comment on how I can improve my build. PMs are welcome too.

1,711 Posts
I have to say you have tenacity and talent so I think you will do well in your car audio venture. There is no way I would have ever attempted to cut my dash or doors the way you tackled it.

Keep up the good work.

18,241 Posts
Dude... your off your fucking rocker. Love it. You have a very bright future. I cant believe you routed those strips of acrylic. Talk about butthole pucker..

seriously though, Your getting good very fast.

669 Posts
Looks really good. Nice to see another Ipad install. Which Car Toys are you working at

469 Posts
Discussion Starter #17
Dude... your off your fucking rocker. Love it. You have a very bright future. I cant believe you routed those strips of acrylic. Talk about butthole pucker..

seriously though, Your getting good very fast.
I snapped one too many MDF templates in the process... Thanks for the encouragement, it means a lot man.

Looks really good. Nice to see another Ipad install. Which Car Toys are you working at
I'm down in tigard off 217/highway 99. Let me know if you ever wanna come by and chat. I've already met with another local diyma member last week.

Sent from my SM-N960U using Tapatalk

3,662 Posts
The first door-handle-relocation I have ever seen!! Nice work across the board, dude! Don't stop...
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