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2018 Base Cayman 6MT, BC coilovers , AP catback, MRR wheels, Softronic tune
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Discussion Starter · #1 ·
Does anyone know if the rear speakers on a cayman run full range and would work well as a high level input? I am going to install a small subwoofer/amp combo in the back of the car.
I have the base audio system, just trying to give it a bit more bottom end. Did want to buy and install a digital to analog box just for a sub.
 

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Does anyone know if the rear speakers on a cayman run full range and would work well as a high level input? I am going to install a small subwoofer/amp combo in the back of the car.
I have the base audio system, just trying to give it a bit more bottom end. Did want to buy and install a digital to analog box just for a sub.
Probably not, directly anyway. The impedance of the amp you want to add is probably pretty high and would saturate with an input intended for 8 ohms. You might be able to put a resistor in series with the added amp to get it to work. A potentiometer would allow you to adjust the subwoofer volume.
 

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Discussion Starter · #3 ·
Probably not, directly anyway. The impedance of the amp you want to add is probably pretty high and would saturate with an input intended for 8 ohms. You might be able to put a resistor in series with the added amp to get it to work. A potentiometer would allow you to adjust the subwoofer volume.
My amp/sub has a high level input designed to take head unit speaker power for the audio signal input. I just wondering if the PCM outputs full range to the rear speakers. I didn’t want to use it if the was a low frequency cut on the rear speakers.
 

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Discussion Starter · #9 ·
My guess is that it is 4ohms speakers and your Nakamichis high lvl input should be rated as such.
I cant see that the rears as full range, they would bottom out fairly quickly...
Thanks, that makes sense. I need to clean my air intake filter. I may pull the rear speakers and see if they have a passive filter on them.
 

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Discussion Starter · #11 ·
Wouldn’t it be easier to pull signal from behind the radio? If so passive wouldnt matter, I assume if they have passive xovers it would be on the actual speaker or very close to them.
My understanding is the head unit only has digital output. I wanted to avoid buying and installing a D/A box for a simple subwoofer add. I removed the rear speakers, they are 4" speakers with no passive network (capacitor, coil or resister) attached to them. I suspect the PCM is digitally doing a low cut to them. I guess I could play a sine wave sweep through the head unit and measure it with an oscilloscope, but I don't have one anymore. I will do more research and testing.
 

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If it's the Base/SPP system, it's analog out of the back of the PCM. If it's Bose or Burmester, it's digital/optical (proprietary MOST150). In which case, the amp is underneath the passenger seat.

For a subwoofer, all you need is the lowpass frequencies, not full range. You could get that from the mid-bass speaker signals.
 

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Discussion Starter · #14 ·
If it's the Base/SPP system, it's analog out of the back of the PCM. If it's Bose or Burmester, it's digital/optical (proprietary MOST150). In which case, the amp is underneath the passenger seat.

For a subwoofer, all you need is the lowpass frequencies, not full range. You could get that from the mid-bass speaker signals.
Thanks for the info. I been checking out your post on your GTS and Spyder installs. I have the base system so no amp, makes sense why I was confused. I did car audio a long time ago in my 20s and competed in Usac sound quality. Maybe I should put the little sub in my wife's car and make the Cayman nice like yours :). The cavities below the rear speakers are begging for a stealth custom sub box. I never use my storage pockets as they are awkward to use and I could easily put it back to stock for the most part with a few parts.

I assume the PCM has the ability to output digital, but the cable isn't ran since no amp on the base system. And possibly the PCM FEC isn't enabled, based solely on how VAG tends to do things. But correct me if I am wrong.

I was going to upgrade my tweeters too, dang to vents don't want to come out. I have pried on them with a tint squeegee at a 30 degree angle, feel like I am going to break them. Thanks for your help and the great info you put in your posts!
 

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Base PCM does have the ability to to be reprogrammed to activate the digital optical output. I used the ZEN-V-PRG to do just that. It's meant as a shop tool (it's reusable on multiple vehicles), so you could either buy one yourself, or find a local shop that may have one that you could borrow/use (likely for a small fee).

A fiber cable comes with the ZEN-V to connect from PCM to the ZEN-V, and then out of the ZEN-V, you can output via toslink into an amp/dsp, or it has the option for up to 12 channels of RCA pre-outs.

Honestly, if I were in your position (and as I've mentioned in my build thread), if you wanted to do something more than just a sub upgrade, I would seriously consider the solutions offered by MusicarNW.

This group buy is now closed, but lots of good info outlined here: GROUP BUY | Musicar Performance Audio Systems for 718/981/991 - Rennlist - Porsche Discussion Forums
 

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Discussion Starter · #17 ·
Here is the update to what I ended doing doing to my car for the sub woofer install.

I got the high level input signal from behind the PSU, soldering to the door mid/bass speakers, thanks to @phroenips for the suggestion.
The auto turn on feature didn't work well on my amp, so I went to the passenger fuse box and used a spade connector on a spare slot and fused the line.
I ran my main power to the junction under the passenger foot-well.
I ran my ground to a factory ground point by the coolant reservoir in the rear.

Some dialing in the crossover and gain, applying some sound damping materials and modifying the storage pocket cover. I am very happy with the results. To the untrained eye nobody would even know I have added a sub to my Cayman.

Now to upgrade the tweeters, dang those vents don't want to come loose.

Hood Motor vehicle Automotive design Automotive tire Bumper


Automotive tire Vehicle Motor vehicle Car Automotive lighting
 

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I’d really like to see more pics of the actual install. What does the sub/amp look like in there? Very clever install.
 

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Discussion Starter · #19 ·
I’d really like to see more pics of the actual install. What does the sub/amp look like in there? Very clever install.
Here is the pics I have, I would like to redo it and put a separate amp under the passenger seat and build a custom fiberglass box for the sub in that space. It did develop a rattle on my long road trip. There is a ton of space in that cavity, it’s very awkwardly shaped.

before install
Vehicle Hood Car Motor vehicle Automotive design

Hood Motor vehicle Automotive design Automotive exterior Automotive lighting
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With sub in and power for the amp under passenger carpet.
 
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