# Audio Do-over in a Porsche Cayman GT4! :) Simple SQ with Mosconi, AF, Audiomobile



## simplicityinsound (Feb 2, 2007)

One of the perks of doing car audio here in california is that with the demographics we cater to, we get some pretty cool and interesting cars come through the shop. I am an avid reader of all the major car magazines and from time to time, there would be a vehicle review that catches my eye and i secretly hope that one day, one such car will come through.

The limited edition, newly released Porsche Cayman GT4 is just such a vehicle. There has been a lot of talk ever since the Cayman debuted that with its natural mid engine balance, if given a bigger engine, it will perform really well...and GT4, using the 3.8 liter from the last gen Carrera S, and a myriad of suspension, brakes and aerodynamics mods, is just such a vehicle. having worked on a handful of caymans and boxsters before, i was always curious, after reading the magazine articles, what one would feel like on the road. but with so few made and even fewer imported, i wasnt very optimistic.

which was why it was so cool when the customer contacted about his GT4...and not only did we get to work on the car, i also had the distinct pleasure of going down to southern california and driving it all the way back up here.

I can report that this is one of the best drivers cars i have ever had the pleasure of piloting. what stood out for me is the low end grunt from the 385hp big straight 6. unlike lesser caymans, this thing pulls with authority even in the tall gears. it sounds great, and is extremely balanced on the road. but the best part for me was the shifter and clutch combo...i have never felt something so balanced, precise yet effortless in a car before, and after the 6 hour ride...and jumping back into my own car, my shifter and clutch pedal felt like poopycock 

so anyway, enough gushing about the car itself, lets talk about the goals.

when the owner contacted me, it had already previous install done on it...but on the way back, i quickly realized why he wanted a redo. the best way to describe the old system, which actually utlized some good equipment, was that it sounded just like a stock premium system.....it had no imaging, no staging, very little midbass, virtually no midbass, and even for me, flat highs. when i pulled out the old system, it kinda became apparent why this was the case as it was truly a subpar install...but for how much i love this car, i wont go into the details of what we found and instead, focus on the rebirth of the system.

first, lets take a look at this gorgeous machine...what is especially amusing are his brakes, ceramic composite discs that are bigger in the back than my car has on the front lol




























the goals for the install, which was mostly performed by me with some help from Jesse:

1. remove subpar previous install and achieve a nice level of sound quality

2. maintain a low key appearance in the interior

3. maintain full use of the frunk, and do a simple and clean install in the hatch area

4. not to add too much excess weight. the previous sytem had a pretty heavy jl prefab subbox in the hatch, and my goal was to exceed that by less than 25 lbs when all said and done.

first up is the custom fuse mount that Jesse fabricated, which securely houses a stinger fuse next to the battery, secured by a factory bolt:














































the oem headunit was kept, and with this being part of the "PLUS" version of the stock system, it features a navigation headunit that also displays various other parameters of the car.










For the front stage, we went with a pair of Audiofrog GB15 large tweeters and GB60 midbasses. the GB15s were molded into the stock A pillars, and recovered in factory matching alcantara. For this car, the key was a subdued and clean look as it is at the end of the day, somewhat of a track machine, so the tweeters were aimed off axis to keep the mold as small as possible:


















































































some quick build pics of the pillars. One cool thing about audiofrog is that the tweeter mounting ring is already pre designed to be molded into the pillar. with a little gap in between the ring and the tweeter when flushed in to upholstery clearance. so here are the supplied metal rings, ground down to bare metal, aimed and attached to a stripped stock A pillar. they are as high as they are to clear the instrument cluster shroud and also the various modules on the A pillar metal so the tweeter can be sunken in as deep as possible.










Mold cloth was then pulled, resin applied, allowed to cure, and the pods were reinforced from the inside via a resin/filler mixture:










then filler follow by sanding gave us two smooth shapes to attach our alcantara:



















and the alcantara was pulled across the pillars:



















then the audiofrog GB15s were wired up and installed into the pillar pods:




























we never ever do a system without a way to control the sub volume, and we always seek to integrate the sub volume module in a way so that only the knob is showing. in the gt4, this presented a challenge as there arent too many places to hide a module. so i took the entire center console apart, and built a little board that houses the bass knob in the old ashtray:



















this simple little piece actually took some work. 

first, i removed the ashtray, cut piece of board roughly to the shape, and then backfilled it with duraglass. 










when that cured, i popped it out, sanded it won and it gave me a perfect match tot he ashtray:










then after several coats of high build primer sanding, it was ready go back into ashtray:










the mosconi bass knob module was disassembled and secured to the ashtray assembly, and then the cover plate press fit on, and the knob reinstalled:



















the GB60 midbass went intot he stock lower door locations. first, i ran new speaker wires into the door and sound proofed the outer door panel with blackhole tiles:




























then the inner door panel received some GP audio STFU composite dampers:










i then fabricated some oem speaker flange matching spacers, and coated them with several layers of truck bedliner to protect them against the elements:










and these were secured to the door using oem hardware:










the GB60 was then wired up and installed:



















and a F.A.S.T. acoustic foam ring was placed around the gb60 to seal it against the grille opening:










the inside of the door card also received some CLD treatment:


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## simplicityinsound (Feb 2, 2007)

and the entire process was repeated on the passenger side:



























































































Now comes the wiring pics. but lets start with the signal source. thanks to Ken at MusicarNW, we found out that the oem signal on the "plus" stock system features a balanced signal between the headunit and amp. so to properly integrate the signal for our mix, we used a rockford BLD balanaced line driver to get us the best clean signal and low noise floor. this was placed and wired up in the stock amp location under the passenger seat. the amp was already missing from the previous install:










from there, the speaker wires all ran down the driver side, while the passenger side got hte power and other accesory and turn on wires, the main rca line, went from the BLD, to the back wall, far away from the factory main power cable, and to the driver side joining the bundle of speaker wires. all the wires are ziptied to factory bundles throughout the car every few inches or less after the entire back half of the car was stripped out:


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## simplicityinsound (Feb 2, 2007)

so thats it for the main inteior. time to move onto the hatch. where all the equipment is stashed. for this part, the main goal was to place all the gear here, leaving the frunk fully empty, and just do a simple and clean install.

to that end, here is the view with the hatch open. a simple fake floor setup with a cutout trimmed in the same black alcantara as the front pillars. in the cutout is a well also lined with alcantara. and when you peer through the meshed opening, you see a single mosconi AS200.4 and an audiomobile EVO2410 10: subwoofer. 

there was no need for a grille or cover as the oem match cover, suspended from the hatch, covers this area fully when closed, nothing too fancy, just simple and clean:
































































lets take a look at how the hatch came together.

first, after stripping off everything, the entire floor of the hatch was covered with a layer of STP CLD damper:










i then built a platform board with an open bottomed enclosure wall, laid it in the car after cutting away from of the stock carpeting to gain maximum depth, and laid down a a few layers of fiberglass to form the bottom of the enclosure:




























i then topped the enclosure off with a piece of black painted mdf, and built spacers on the side with threaded inserts in them to secure the top layer:




















with most of the construction out of 1/2" mdf and fiberglass, this entire structure actually weighs about the same as the previous prefab enclosure even after the sub was loaded into it.

i then wired up the dsp on the driver side and the mosconi AS100.2 for the subwoofer (500 watts rms)



















andt hen this structure was loaded back into the car, and secured:




























these are the pieces that make up the top layer. whcih is a bottom board, a side wall structure, and two spacers for the amp. these were then wraped with alcantara:



















the two spacers were painted balck and bolted to the bottom piece"










and the mosconi AS200.4 wired up:










this was then bolted to the car and everything wired up:










and the well side wall structure secured:










these are the two side spacer pieces i built to provide support to the sides of the fake floor:










and these were bolted in place with rivetnuts, still fully removable if someone needs to access the side places to replace bulbs:




























and finally, here are the two floor and trim pieces before and after vinyl alcantara and painted aluminum mesh:














































so, thats it for this car. even with a stock headunit, this car sounded really really good. I took her down to LA and on the way stopped at audiofrog for Andy to take a listen as well.

after some playing to account for the off axis install of the tweeter, i got the center to be pretty solid and a few inches above the dash, with very good depth, width is pillar to pillar, and the tonality of the car was quite good. smooth, laid back with a lot of midbass punch. 

what was really nice was the subbass. in the other caymans we have done, the car's interior seems to have shown a natural tendency to create a bump around 50hz and then drop off a bit below that freq. on this car, not sure if its the sub, the interior materials, or the amp partially suspended over the sub, did not exhibit much of this at all...it was almost flat all the way down. and in listening, it was very full bodied and blended well with the rest of the system.

needless to say, the 6 hr drive back down to deliver the car was far far more pleasant than the drive up 

until next time,

Cheers,

Bing


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## Lycancatt (Apr 11, 2010)

curious if you remember where you crossed over to the large format gb15s, out of all audiofrogs products, the gb15 tweeters are what I really want to check out.


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## simplicityinsound (Feb 2, 2007)

Lycancatt said:


> curious if you remember where you crossed over to the large format gb15s, out of all audiofrogs products, the gb15 tweeters are what I really want to check out.


i think it was around 2khz? maybe 1.8 at the end? 24 db lr


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## 1FinalInstall (Oct 13, 2013)

Incredible work, looks amazing SIS!


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## sinister-kustoms (Jul 22, 2009)

Another superb install in an incredible car! 

Can I ask why you're still using MDF for door mounted speaker adaptors though? I know it's very dry where you are, but HDPE is 100% guaranteed insurance against swelling.


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## frontman (May 1, 2013)

Beautiful install as always!

Just curious - were you able to meet your goal of shaving off 25 lbs in install weight upon completion?


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## Alrojoca (Oct 5, 2012)

Nice Car, and great install!

I see like a black foam with some kind of square shape or texture behind the midbass mounting plate, it looks to me, like Yoga mat CCF, ha ha. If not yoga mat material, some kind of fancy CCF between the inner door and the baffle plate, with some squares. 

Is that what that is?


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## Dumple (Dec 16, 2010)

amazing looking ! you sure do some great looking work. Ive seen the wrx with all the mosconi pico amps in person that was fantastic!!!!


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## simplicityinsound (Feb 2, 2007)

sinister-kustoms said:


> Another superb install in an incredible car!
> 
> Can I ask why you're still using MDF for door mounted speaker adaptors though? I know it's very dry where you are, but HDPE is 100% guaranteed insurance against swelling.


I know everyone's loving hdpe...and maybe one day I will switch but after pulling out Bedliner coated mdf rings that have been through 8 years of weather (we do have 3 to 4 months of rain season a year) and it looks the same as when i installed it...kinda makes me say "why fix what's not broken?" Im kinda slow to evolve sometimes haha I do still feel there r some advantages of wood over hdpe. For installs that r going to wetter climates I use acrylic. 


Sent from my SAMSUNG-SM-N930A using Tapatalk


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## simplicityinsound (Feb 2, 2007)

Alrojoca said:


> Nice Car, and great install!
> 
> I see like a black foam with some kind of square shape or texture behind the midbass mounting plate, it looks to me, like Yoga mat CCF, ha ha. If not yoga mat material, some kind of fancy CCF between the inner door and the baffle plate, with some squares.
> 
> Is that what that is?


That's Blackhole tile ?

Sent from my SAMSUNG-SM-N930A using Tapatalk


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## simplicityinsound (Feb 2, 2007)

frontman said:


> Beautiful install as always!
> 
> Just curious - were you able to meet your goal of shaving off 25 lbs in install weight upon completion?


My goal was to exceed the weight of the previous install by 25 lbs or less. Yeah I think im well below that 

Sent from my SAMSUNG-SM-N930A using Tapatalk


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## Alrojoca (Oct 5, 2012)

simplicityinsound said:


> That's Blackhole tile ?
> 
> Sent from my SAMSUNG-SM-N930A using Tapatalk


Thanks Bing.

I've noticed the factory head unit is being used, based on the information you posted, sounds like it already had RCA's, or used speaker wires out and just needed a balanced line driver as you indicated.

My question is how do you convert, use or bypass a non balanced signal, or what is the optimal device/adapter you use to deal with the fiber optic signal found in many of these Porsches, that seems to be a big issue with these cars, wanting to keep the factory head unit and adding big aftermarket amplifiers?


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## hatnlvr (Jan 28, 2012)

Beautiful install! Great work


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## ageggatt24 (Aug 17, 2012)

Great detail.


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## Mless5 (Aug 21, 2006)

Nice install!

I spotted a secondary grill on the door panel with what looks like a port behind it for midbass - am I correct? It seems like you've left that arrangement untouched, do you feel like there is a benefit to this config vs "sealed" door?

Thanks.


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## jtaudioacc (Apr 6, 2010)

so does it sound better than with the Ultima speakers? lol


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## simplicityinsound (Feb 2, 2007)

Mless5 said:


> Nice install!
> 
> I spotted a secondary grill on the door panel with what looks like a port behind it for midbass - am I correct? It seems like you've left that arrangement untouched, do you feel like there is a benefit to this config vs "sealed" door?
> 
> Thanks.


Thsts a sealed cup where the midrange used to be.  

Sent from my SAMSUNG-SM-G935A using Tapatalk


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## simplicityinsound (Feb 2, 2007)

jtaudioacc said:


> so does it sound better than with the Ultima speakers? lol


Don't know as I never tuned that other car...have u heard it down there on one of your visits to orca? 

Sent from my SAMSUNG-SM-G935A using Tapatalk


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## juiceweazel (Jul 28, 2014)

Clean install that looked near factory. Outstanding work!
Quick question. It appears the sub is partially covered by the amp. I've never seen this. Do you ever have problems with this causing damage to the amp, long term?


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## simplicityinsound (Feb 2, 2007)

juiceweazel said:


> Clean install that looked near factory. Outstanding work!
> Quick question. It appears the sub is partially covered by the amp. I've never seen this. Do you ever have problems with this causing damage to the amp, long term?



not in my experience...the most extreme example of this was my last car...and 3 years later, still running strong and problem free...

http://www.diymobileaudio.com/forum...legacy-gt-mosconi-morel-arc-updated-c3cx.html

i almost did that on purpose in this car...as the previous caymans in the past, i have had issues of the interior causing the lower bass to drop a lot when the doors are closed, so on this, just for ****s and giggles, i wondered what happens if something solid presented a loading baffle to the sub in the car, didnt think it would do anything.

but for some reason, the bass extension in this cayman, compared to the otheres, both by ear and by rta, was better. again, could be just something else entirely, but i dunno.


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## juiceweazel (Jul 28, 2014)

simplicityinsound said:


> not in my experience...the most extreme example of this was my last car...and 3 years later, still running strong and problem free...
> 
> http://www.diymobileaudio.com/forum...legacy-gt-mosconi-morel-arc-updated-c3cx.html
> 
> ...


That's interesting. I'd be curious how the amount of sub covered affects certain frequencies. I'm sure the Italian quality doesn't hurt either.
Great build on your personal ride as well. Almost zero spacial sacrifices for what I'm guessing is still a great sounding vehicle. I find it amazing the rubber mat doesn't affect output considering the rubber could be considered a sound absorber of sorts.


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## simplicityinsound (Feb 2, 2007)

juiceweazel said:


> That's interesting. I'd be curious how the amount of sub covered affects certain frequencies. I'm sure the Italian quality doesn't hurt either.
> Great build on your personal ride as well. Almost zero spacial sacrifices for what I'm guessing is still a great sounding vehicle. I find it amazing the rubber mat doesn't affect output considering the rubber could be considered a sound absorber of sorts.


the mat nothing, the full floor closed up may affect output a bit, but i still can get quite loud in the car on bass. it was a compromise made to make sure i loose zero trunk space 

b


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## Gmeover2016 (Feb 7, 2018)

Alrojoca said:


> Thanks Bing.
> 
> I've noticed the factory head unit is being used, based on the information you posted, sounds like it already had RCA's, or used speaker wires out and just needed a balanced line driver as you indicated.
> 
> My question is how do you convert, use or bypass a non balanced signal, or what is the optimal device/adapter you use to deal with the fiber optic signal found in many of these Porsches, that seems to be a big issue with these cars, wanting to keep the factory head unit and adding big aftermarket amplifiers?



Did you ever get a response from your question above.... just curious because I am having this issue with my 991 Burmester system


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## Redlining (Nov 7, 2017)

A truly fantastic execution for a two-way system!

I gotta say I'm pleasantly surprised by your insight about the audiofrog components, in fact, may I ask, how well would a GB15 fair against a system with a GB25+GB10 combo? Is it an impossible comparison?


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## carlr (Feb 27, 2011)

As always a spot on install!


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## Eskimo (Jan 13, 2008)

Gmeover2016 said:


> Did you ever get a response from your question above.... just curious because I am having this issue with my 991 Burmester system


Interested in this too!


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## Redlining (Nov 7, 2017)

Eskimo said:


> Interested in this too!


I believe it'd be necessary to use a fiber optic over MOST interface. 

Audison (IIRC) makes this one interface called Bit DMI with this exact purpose in mind; it even provides a regular TOSLINK connection for keeping the signal digital to any other DSP.


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## JimmyDee (Mar 8, 2014)

Redlining said:


> I believe it'd be necessary to use a fiber optic over MOST interface.
> 
> Audison (IIRC) makes this one interface called Bit DMI with this exact purpose in mind; it even provides a regular TOSLINK connection for keeping the signal digital to any other DSP.



We're kinda digging this one back up from the grave...

But the Audison Bit DMI is just an Audison branded mObridge unit.
mObridge allows Audison to distribute the DA1, under thier own name.

If you want to integrate into a pre-2016 Porsche, then check out the mObridgre products:
Products | mObridge


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## Redlining (Nov 7, 2017)

jimmydee said:


> We're kinda digging this one back up from the grave...
> 
> But the Audison Bit DMI is just an Audison branded mObridge unit.
> mObridge allows Audison to distribute the DA1, under thier own name.
> ...


That's always neat to know! 

A few interested users here questioned themselves how to interface the MOST bus, so well, I think my google-fu served well!


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## Gmeover2016 (Feb 7, 2018)

thanks for the info..... but what is the major difference between a 2015 991 and 2016 991........it appears to be the same PCM


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