Car Stereo Installation

mtelliott · 07-17-2007, 12:55 PM

Before I get into it, I thought I would ask a few questions.

From what I have read, it seems that putting in an aftermarket stereo isn't a trivial exercise. Looks like it's got pre-amp wires runnign from the head unit to an amp mounted somewhere. Then the crossover is built into a dial near the driver's seat?

As well, there's not a true crossover in the door panels.

So, how does the wiring really run? What's in there? Etc.

Michael

Danglerb · 07-17-2007, 04:51 PM

The "whats in there" answer is easy, nothing you want to keep.

Porsche sends a stereo speaker level signal to a front/rear fader next to the driver seat, and I think the amps are next to the passenger seat, so wiring nightmare back and forth, and none of it useful or high quality.

Pre 84 has the speakers mounted behind a flat perforated grille and the depth is VERY limited if you don't want to cut holes in the metal doors or mount grilles over the door panel. My factory speakers were totally toast the foam surround turned to dust so the "speaker" paper wasn't attached to the speaker frame.

Out it all went on my car.

Rubber ducky 11" antenna replaced the factory goes up and down all the time thing.
JVC KD G720 AM/FM/CD/MP3 with a front USB went in the console and powers the door and rear speakers directly, with a sub output to a 8" powered Bazooka tube in the hatch area.
Two pairs of Alpine 3.5" speakers went in the doors, with I think 5.25" in the rear.

I rate the sound as very good, and thats without any real tuning yet. Putting the bass through the powered Bazooka works wonders, and it does play pretty loud, MUCH louder than what many 500 watt dual 15" types might lead you to believe.

mtelliott · 07-17-2007, 07:42 PM

So, you ran all new wires to both the fronts and the back? I tend to do my own work. Have nice PPI amps (old school - not Asian made crap).

So, rip out / bypass what's there and run new wires to both the fronts (I'll put in MB Quart with crossovers) and the back with a seperate sub running in the back.

It's to be my winter project.

Thanks for the info.

Michael

Michael

Nicole · 03:16 AM

My previous 928 - a 91 GT - had a "professionally installed" aftermarket stereo system with upgraded speakers in the doors.

Well, as it turns out, the "professional" installers ("professional" meaning: They got pay according to their qualification - both of which were low) did some rough cutting into the inner metal of the door, in order to fit these huge speakers. Then they screwed those heavy suckers directly onto the door panels, but not through to the metal.

Oh, I forget - there was no metal left where it would have helped...

The result: Not only was the car butchered - if anyone slammed a door, the four screws would come lose and the speaker flop around.

I don't remember which of those "professional" chain store installers it was, but you can be sure I will avoid such establishments as long as I live!

Fortunately, I found a really good car stereo shop nearby (Soundwave in San Carlos, CA) where the owners work on the cars themselves - and they have done numerous 928s already. They know the systems that are in there, and what can be done to upgrade or replace them while preserving the factory look. Great guys!

Danglerb · 07-18-2007, 07:04 AM

Shops may farm out the installs, and really the last thing you want is somebody getting paid a flat price for the job messing with your old Porsche. What needs to be done is taking it slow, and being willing to STOP while sorting out problems. If a speaker doesn't fit, and those Quarts won't fit behind the door panels unless you have panels from a newer model, you need to be willing to calmly put it back as it was, or leave it open until you get speakers that do fit.

The door panels don't like rough treatment either.

I like music, news, etc., but the real sound system exits from the rear via 3" pipe. Also I wouldn't want anything showing that makes the car a target for theft or breaking into.

Alan in AZ · 04:32 PM

I would reuse any stock speaker wiring unless you are going for a very high power system - just saves a lot of fishing... the rest I agree - best to junk it all...

I have not exactly lived up to this advice on my car - but I can tell you it is a huge amount of work to pull everthing again and do it well - mine needed it it due to power & recongiguration - but most won't.

Alan

mtelliott · 07-18-2007, 03:03 PM

So, do you pick up the speaker wire from the Amp location.

Please note, I haven't pulled anything yet. Just looking at wiring diagrams (which can be tough). If I can just run wires from my amp to wires at Porsche Amp location, I'm good with that. But, then, Porsche has that fader built in to the system so do wires run from the Porsche Amp to the fader and then out or what?

Michael

buskey · 07-20-2007, 05:02 AM

The resounding message here is be careful who you turn your beloved Porsche over to for stereo (or any) work.

I was a mobile audio installer (14 yrs) back in the days when these cars were new and I clearly recall working with many installers over the years who had no clue and no business working on anything, let alone a $60,000 high performance work of art.

Time and time again I found myself cleaning up after some of these guys and to this day I cringe at the thought of guying a Porsche that has had anything beyond the head unit replaced as I know what kind of trouble can lurk behind the door panels and carpeting.

Great advice has already been given here so I will not attempt to pile on my own but do be wary of the big-box electronics retailers, I would not trust most of their installers to drive my car into the shop let alone pull off trim or panels.

mtelliott · 07-20-2007, 05:17 AM

Buskey,

So, would you run new wires or tap in to the old. And if you are tapping into the old, where is the best place to tap?

Michael

buskey · 07-20-2007, 06:48 AM

I don't recall the exact setup on the '85 but I assume it would be similar to my '87.

The ideal situation would be to run your own wires to each speaker in the car but not everyone is comfortable removing the interior panels and carpeting to the point to make this feasible, not to mention pulling additional wires through the door grommets, securing them inside the door, etc. If you are OK with doing this then I would recommend it.

If not, using the factory speaker wires should be fine so long as the wiring is in good condition. There should be a factory amp under the panel between the pass seat and door sill. If so, that is a great place to grab the factory wires.

If you do not have the factory wiring diagrams and do not know which wire goes to which speaker, strip the ends of each wire pair and use a AA battery - hold one of the wires to the negative end of the battery and quickly touch the other wire to the positive end, you will hear a small "pop" out of the speaker and this poses no risk to the speaker at all.

All of the brown wires in each pair will be the negative speaker wire, the other colored wire will be the positive.

Hope that helps -

Bill

mtelliott · 07-20-2007, 07:38 AM

I'm comfortable with fishing wires. Haven't pulled the door pannels but found a great writeup on how to do it so I'll probably go that route. Just seems much cleaner to run new wires.

I've run new wires throughout my 911 so not an issue, just takes time. I might just junction them in at the amp for now until I have time to properly run everything.

Last question, who makes a good stereo now? I want to go with HD tuner to pick up some of the new channels that are available in Denver (figure the reception has got to be better).

Michael

buskey · 07-20-2007, 07:45 AM

Michael -

Fly me to Denver for the weekend (during the winter) and I'll do the install for you

mtelliott · 07-20-2007, 08:18 AM

Only if I can come up to do the same

.

We do have some excellent skiing here. If only I could afford another place in the mountains.

Michael

Danglerb · 07-20-2007, 11:16 AM

Maybe I have it wrong, but don't you want to tap into the factory wiring after the fader next to the driver seat? The signal to and from the passenger side amp is stereo, and most will prefer not to use a POT to set front rear balance since head units have it built in and include 4x channels of speaker level outputs. Use the pot and you only get half the head units power, 2 channels.

Doing the wiring "right" could be something to save for a major interior removal. I'd settle for a clean working install tapping into the existing wiring.

Check each of your speakers, carefully. During my PPI one of the items was radio does not work. 10 minutes with the manual a few weeks later and I found the front/rear fader set to all front, and the bass/treble to all bass. Front speakers had rotted surrounds, which means no bass, so I got no sound. Centering the controls (the old push and twist type) gave me ok sound, very treble in front, an sort of ok in rear.

When I pulled my door panels and saw the rotted surrounds I assumed the rears were in the same shape. Turns out they used a different surround material or something and were fine, but I found that out several hundred bucks later after paying to pull the rear seats, rear panels, and put in new speakers. If I had listened to each driver one at a time, using front/rear and left/right faders, I would have saved all that money and time.

I don't see a "lot" of difference in quality between the better major brands, but things often change from one year to the next. What they look like, and what features are supported is how I made my choice. I am sick of all push button radios, I wants some KNOBs. Other requirement were good MP3 support with a front USB port I can plug a thumb drive into, subwoofer out, non motorized door, and removable face.

Some of the head units do NOT match up well with the older look of the 928 console, space age chrome and flashing multicolor displays, yuck. Crutchfield is a good place to browse the models and features.

shadowknight · 07-27-2007, 12:51 PM

not trying to hijack the thread but does anyone have the original stock connector for the radio they would be willing to part with/sell????

Danglerb · 07-27-2007, 02:12 PM

Quote:

Originally Posted by shadowknight

not trying to hijack the thread but does anyone have the original stock connector for the radio they would be willing to part with/sell????

Which model year, which radio, which side of connector car or radio side?

At least a "fair" chance the connector is available in some fashion from the aftermarket.

Best to start a new thread so your question will be noticed sooner.

mtelliott · 09-12-2007, 02:41 PM

Quote:

Originally Posted by Danglerb

Maybe I have it wrong, but don't you want to tap into the factory wiring after the fader next to the driver seat? The signal to and from the passenger side amp is stereo, and most will prefer not to use a POT to set front rear balance since head units have it built in and include 4x channels of speaker level outputs. Use the pot and you only get half the head units power, 2 channels.

So, I'm looking at the Fader today and it has 12 wires (6 pairs) going into / coming out of it. I'm guessing that you have 4 going out and two going in. But, that makes no sense. Unless you have a right side coming in through one pair, a left side coming in through another pair; and then the fader sending out two pairs to the front (left and right) and two pairs to the back (left and right). But then, there's two sets of speakers on each side of the rear. So, how in the heck did they engineer this one?

And since the wires are either black, or red/black, how do you know which one is incomming and which one is outgoing?

Thoughts?

Michael

Danglerb · 09-12-2007, 04:24 PM

With the head unit disconnected you can click the speakers one at a time with a penlight battery.

Any idea if the wiring is original or still hooked up?

Hmmm, you have 10 speakers, maybe 2 in, 10 out?

Alan will know for sure.

mtelliott · 09-12-2007, 05:36 PM

Each front speakers take a single pair to run both. They run both wires to each speaker (woofer and tweeter) with a capacitor in-line with the tweeter to block low frequencies. Or at least, that's how I think they do it. Then there's the middle speakers (by the rear passenger's knees, then there's the far back speakers. I'm guessing they take a pair to run both left rears and another pair to run both right pairs.

My plan was to disconnect from the fader, disconnect the head unit like you mentioned, and then using a battery figure out which pair goes to which speaker. I can then run wiring from an amp I'm planning on installing to those wires. When I'm truly ready to have awesome sound, then I'll replace the speakers and fish wires through holes. I'm just not looking forward to that one.

mtelliott · 04-12-2008, 02:07 PM

Update.

So, I figured out the wiring. Right at the amp, you can bypass everything. Wires run from head unit into wires running out of amp. Left the amp in there for now.

Going on-line to find speakers. Not going to get the focal's (they are good but they are expensive). I like MB Quart so I'll lean towards them. Not sure how I'm going to do the crossover but my experiement with wiring it up without taking the door panels off.

It looks like 4" in the door, and 6 1/2" behind the seats. With some work, I think I can get some decent sound going. I'll work on speakers first, then wire in my amp later. Probably would have made more sense to do it all at once however I wanted to do it in stages.

Michael