2019 Porsche 718 Cayman GTS - SQ install

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** Reposting/archiving from DIYMA **

I'm ready to start the build on my Cayman! Got some good experience as I've been doing my 4Runner build as well


My goals for this build is to keep an OEM look, but obviously improve the sound quality. I just want it to be subtle. Just like the color of the car:





I'll be repurposing some Hertz Mille ML1600 and ML280 for a 2-way active system. I want a subwoofer, but I'm limited in available diameter. Most I can do is an 8". Based on the advice of my local shop, and their knowledge of my tastes, they suggested the JL Audio 8W7AE-3 (depth isn't nearly as much of a problem as height). I'll be doing a sealed fiberglass enclosure.


For signal, I'm using the NavTV Zen-V MOST-150 adapter, and will feed an optical signal to the amp/dsp. I know some people will choose to use high-level inputs and sum the channels, I think this is the better, simpler method.


I was planning to use the JL VX1000/5i to power it all, and actually ordered one. I know some other people have used them in their Porsche installs, putting it under the passenger seat. I did a mock/dry fit, and I didn't feel comfortable with the amount of strain it would put on the pigtail cables.


As I was looking though, it's wider than I was expecting under there, and I believe I can fit two smaller amps, side by side. I'm instead going with the Audison AP F8.9 for the front stage, and the AP1 D monoblock for the sub. As a "bonus," I'll now have enough power and channels to go 3-way in the future if I wanted to Hell, I may even just try the mids that are in there now. If I don't like it, I can just mute those channels, and everything would be ready to go if I chose to buy some better midrange speakers at some point.


Ok, onto the build! First up, sound treatment. The Cayman is a LOUD car. Surprisingly, not so much the engine noise, but road and tire noise. I dabbled with some MLV on the 4Runner build, and it was enough to teach me that I NEVER want to deal with that crap ever again. Such a pain in the arse! I'm using Soundskins Pro and hope for the best.


P.S. I ripped apart a brand new Porsche within a week of ownership. All my friends think I'm nuts for some reason

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This car has the "Sound Package Plus" system, which is the "base." It consists of a 3-way front stage, and 2 rear speakers (tweeter sized). The woofers and the mids are in the door, and the front tweeter is on the dash, actually under the air vent modules. Here, you can see the woofer and mid





The tweeters were more difficult to get to. Those vents are firmly held in place! I have to give a huge shout out to Elevated Audio, who were kind enough to help me figure out how to remove them. There are two sliding latches, four spring clips on the side, and one rear clip, all holding it in place. And between the shape and the damn windshield being in the way, there's no good way to get much leverage. When the clips are released, it comes up and out at around a 30 degree angle. Once it's out, the tweeters are simply clipped into place (it's not fully clipped in in this picture):





And here's what the vent itself looks like for anyone else trying to figure out how to get it out:

















Now I just need to figure out how I'm actually going to mount the new tweeters. I'll definitely need to cut away some of the plastic that originally surrounded the OEM tweeter. More problematic, there's no screw holes that I found, which I could use to make an adapter. I think I might have to resort to using double sided mounting tape, or a glue or something similar. I'm not in love with any of those ideas though, and am open to suggestions if anyone has any other ideas.


BTW, in the SPP, the mids and the tweets look to be on the same channel (same colored wires). Good news though, running new speaker wires to the tweets is super easy and straight forward.


I also went ahead and took out the seats, some trim pieces, the carpet, and the head unit (PCM 4.0)








I finished up the day soldering some 16/4 speaker wire to eventually send signal from the new amp to the speaker locations in the doors.


Next, I'll probably focus on figuring out the tweeter situation, then maybe run power. Might be able to start on speaker adapters as well.

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I've been cross-posting this over on the 718 forums as well. And it was requested I take measurements of the space under the seat, so here they are:


About 8.5" front to back





Technically, 20" side to side, though the grounding screw takes up some space. I'd say 18 to 18.5" usable





Height/depth is also a concern. The front is taller than the back, and you'll need to be mindful of the seat rails that follow that angle


2.5" up front, and 1.5" in the back

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Onto the build update! I was apprehensive about hacking up my brand new Porsche to fit the tweeters, so I did what any reasonable person would do: ignore it and work on something else!


Used the trusty router to make some speaker adapters. First made templates out of MDF, then transferred that to acrylic. To get the depth I needed/wanted, I'm stacking a total of three layers. The first is 1/4", and will be the part that actually screws onto the door panel, then two 1/2" rings, slightly smaller in diameter. Used acrylic cement to bond them together, they're still curing right now. Should be able to drill/tap holes for the speakers and mount them up tomorrow.





And I went and picked up the new amps. They fit! And much better than the VXI





I was going to run power to them, but realized that they only accept up to 8 gauge wire. All I have on hand is 4 gauge. Sigh. Ordered some 8 gauge from KnuKonceptz. I can at least still use the 4 gauge to the distribution block. There's a handy OEM distribution block right in the passenger footwell. I liked it, so I put a ring [terminal] on it (That's a Beyoncé joke).








And the small distro block will be right behind the monoblock amp:





Well, that's all I can do until the 8 gauge arrives. Now what? Ugh, fine, tweeters.


This makes me nervous...





I ended up cutting away the plastic surround of the OEM tweeters, and pulled out the metal clips that held it in place.











But it looks like it's going to work!





As for securing them, I think I'm just going to have to use some double sided mounting tape and/or hot glue. I looked again for a way to mount them onto the removable vent piece instead, but there's not enough clearance there, and even if there was, with the way it slides back into place, it would interfere with other areas on its way into the dash.


I finished up the evening with soldering, more soldering, and even more soldering, for the connectors onto all the various end points.

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Small update


Had some techflex laying around, so I wrapped my power cables. Provides zero functional benefit, but it looks cool!








The 8 gauge wire came in, so I finished running power





I was searching for a place to mount the Zen-V, and was originally thinking on top of the PCM. Here's what the back of that looks like:





But by the time I plugged in all the other wires, and tried to put the PCM back into its hole, it didn't fit. I'll have to put it in the passenger footwell area instead.





I used the ZEN-V-PRG to reprogram the PCM to send signal out of the optical MOST plug, and while I saw light coming out, the radio itself showed a message "Audio not available." Hmm. In the instructions, there's a way to do a bit of a "hybrid," where it'll send signal out the internal amplified channels, and the fiber optics. I tried that, and that got rid of the "audio not available" message.


I think I'm also having issues with the ZEN-V module itself. When I first give it power, I see the toslink port light up, but after a few seconds, it goes dark again. I already checked, and it's at the latest firmware. I think it might be having issues properly decoding the MOST signal. I'll have to give them a call on Monday.


I did end up getting the tweeters mounted too! But in the excitement of it all, forgot to get pictures What I wound up doing was using double-sided mounting tape. One layer on the plastic bits of the car, to contour to that; then a couple pieces on the back of the tweeter itself. This seemed to provide enough coverage, material, and thickness to make a good enough adhesion. I can't lift it up with my finger, but if I needed to get it off to replace a bad tweeter, or just try something new, I'd still be able to. So, I'm happy with it.


I'm getting so close, I can taste it! Drilled and tapped holes in my speaker adapters. And on the LAST F$#!@@!@%* hole, my tap breaks off! I cannot express all the feelings, emotions, and cursing that followed.





And that concluded my day, I'm off to get a beer or three with some friends.

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Here's a couple more pictures of the tweeters:








And I got a new tap and die set, and was able to finish up the speaker adapters.





Since the tap broke off in one of them, and I wasn't able to get it out, I had to rotate the speaker to make new holes. Now it'll be out of phase!!





One final test, all checked out, so I put the door panels back on. Still leaving the vents off, juuussstt in case.


Now all I can do is wait until I can talk to NavTV support.

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I can finally put the car back together!


In order to get the vents to fit over the tweeters, I ended up having to dremel away some interior bits of plastic on those pieces as well.


Here's what it looks like before being molested:








And after:








I had checked the amp/dsp firmware already, and it was up to date. I knew there was a firmware update available for the DRC, so I went to go update that. And the computer program said the update failed, and the DRC broke It simply said "Erase completed"


Tried a different computer, couldn't even get all the requisite software installed on that one. Time to call my friends at Elevated Audio again. In the state in was in, they taught me that I could press the Escape button, and it would put it in "boot mode." They also admitted these things can be finicky, and asked if I could bring the car down so they can troubleshoot. Worst case, they have another DRC in stock that they could swap out for me.


That's what I did, I showed them what I did, we put it in boot mode, and tried to install the firmware again. Same results.


Tried on their shop laptop, and it worked without a hitch. Sigh. Well, at least it's up and running now. Here's where I decided to mount it. And with the DRC MP, you can choose between 42 different colors. Anyone want to guess what color I chose?


MOAR YELLOW, of course!!





After all this, how does it sound? I'm very pleased. It still definitely needs a subwoofer.


I was tinkering around with having one preset as my "2-way tune," and setup the other one as a "3-way," using the factory midrange speaker. I've got the 2-way tune about 90% there; the 3-way needs some more work. But that's just for frequencies and tonalities. Comparing the soundstage of the two is pretty revealing.


At least for this car, with the factory speaker locations where they are, I much prefer the 2-way. In that configuration, the tweeters are crossed lower (I'm doing 2250Hz right now), which raises the soundstage much higher. In my 3-way tune, I have the mids doing 500-3k; then tweeters start at 3k. 24db Linkwitz-Riley all around. And the soundstage plummets down to around mid-torso. I'll still play with the tuning, but so far, I'm thinking I'll just stick with the 2-way setup as per my original design. Not a bad thing, that means I can save money on not buying better mids!

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Oops, I did a thing





I was extremely close to getting a cheap pair of Dayton RS100P-4, but I knew that even though I knew it would sound better, I would still be wondering how it would sound with speakers matching the quality of the rest of my system. So, I saved up some extra money, used a couple rebate gift cards I had laying around, and ordered them from my local shop.


I had some leftover 1/4" acrylic, so I went to make some speaker adapters. The ML700.3 has really small mounting holes (it comes with 2.5mm screws), and my tap and die set couldn't do anything that small. I tried pre-drilling holes and using the provided screws, and of course the acrylic cracked :mean:


Fortunately, I was able to use the 3D printed adapters that flgfish so kindly sent me (designed for the RS100P). The speaker opening was a little too large, but it was close enough. I used the speed clips that came with the speakers to secure things a little bit better.





Put it quick tune on it, and I definitely got the extra volume I was looking for. I got an extra 8-10 dB! It was so dramatic, I finally measured the impedance on the OEM midrange, and discovered they are 8 ohm speakers (DC resistance measured at 6.5 to 6.6), so that explains that.


I did a quick re-tune, I'll give it some break-in time before doing a more thorough tuning. For now, at least it doesn't sound any worse! lol

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Work, life, and a healthy dose of procrastination has prevented additional work on this build. All that has finally been overcome.


Let's get started








Car side part done. It was quite stubborn to come out, but I eventually got it.





Except apparently I completely missed some hard to reach corners. D'oh!





At least it was sturdy enough at this point where I could "patch" it on a bench where it's easier to access. I had to buy more resin, and decided to get some yellow pigment instead of black. Because it's fun!





Time to stretch over the cover. I got some cheater stretchy material from the fabric store





More glass. Boy, is this fun





...aaaand we're done!








So, good news, it's done, and it sounds fantastic!


Bad news, the only way I could secure it to the vehicle was with a screw from inside the box. So, in order to take it out, I'd have to remove the sub itself from the box first.


Bad news^2, this is a mid-engine car. To even change the air filter, and for some other service, I'd have to remove the enclosure to access the engine, etc. So, at least once per year, it would have to come out for annual service.


Bad news^3, I need a grill to protect it from cargo back there. With the grill bars in place, and glued in like they're supposed to be, I could no longer remove the sub, which is required to remove the enclosure.


So after all this time, effort, and expense, I don't see how this is going to work.


Sigh.


Even before realizing this, I was thinking to myself that if I had to do it all over again, I'd just get something like a pre-fab CS110LG-TW3 (which would fit back there), strap it down, and I'd be able to quickly and easily remove it for service, track days, autocross, etc. So, I may end up going down that route after all, and selling the 8W7AE. It's a shame, 'cause that 8W7AE really does sound good!


After I've had some time to cool down and think about it, I could maybe do something with straps that attach to the trunk tie downs, then come underneath, and then up on the “face” of the fiberglass enclosure. The straps would be slightly “ugly,” but still better than a lame “rectangle box in the trunk”


Otherwise, the car audio shop was saying that for the bars, they actually typically just install them with a friction fit, leveraging the carpet to provide an extra tight fitment. Takes some work to get them in and out, but it’s not permanent. Honestly, I’d prefer the straps at this point. Way easier, even if it’d be a little uglier. I’ve got an appointment with them on Monday so we can look at it together and brainstorm.

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Box is done!





It looks so good, I'm rethinking if I really want/need to do straps. My next task is to see if I can modify the plastic trim piece to be able to take it out (and eventually access the engine compartment) with the sub still in place. Worst case, to replace that trim piece, it's only ~$60 for a new part.


Meanwhile, I'm just enjoying the system. I'm incredibly pleased with how it all sounds.

UPDATE: I recently finally got around to attacking the car with the dremel again. I was able to cut back the trim piece enough to be able to get it in and out without having to remove the sub enclosure. That means I'll be able to access the engine compartment (to replace air filter, etc), without having to completely remove the sub and the enclosure. So, I'm just going to leave it as is, no ugly straps for me!