Warpig

Going from the wiring diagram of a late model 95' (not sure it's the same as a 96' but I imagine the method Porsche uses to wire their cars doesn't change much.) With the hi-fi option the rear speaker wiring on the 95' wiring diagram is is follows.

Rear Left (Drivers Side) Brown/Yellow = Negative (-)
Rear Left (Drivers Side) Yellow = Positive (+)

Rear Right (Passenger Side) Brown/Red = Negative (-)
Rear Right (Passenger Side) Red = Positive (+)

Typically Porsche uses Brown wires to show ground or negative
They also seem to use Brown with a color stripe as a speaker negative (-)
and the solid color matching the stripe color as the positive (+) for the speaker pair
so if you want to get you phase correct connect each speaker's negative terminal to the brown wire with the stripe and connect the solid colored wire to the positive terminal.

Also the front speakers on the Hi-Fi option appear to have a high frequency pair of wires coming out of the amp and a sub (low frequency) pair of wires coming out of the amp. The rear channels only show one pair per side which would lead me to believe they are full range. The may not be... if the amp has a built in crossover that only outputs high frequency to the rears because they are designed to work together. It strikes me as odd though that the speakers you have dropped in don't seem to work right with the Nokia amp.



Nick

Sean Hamilton

G'day Noah. To check your Nokia amp try temporally swapping your rear Kenwood 4" 3-ways with your front Pioneer 5 1/4" 2-ways….?
I fitted the Sony 4” coaxial 2-ways to the rear and they work fine.
let us know....
Sean.

DC from Cape Cod

Out-of-phase would make little or no difference on a 4" speaker with no low frequencies.

However, the pair he bought might just not be very efficient. Efficiency is measure in db at 1 meter with 1 watt of input power and is listed on the boxes. A difference of 3db is a noticeable increase corresponding to a doubling of amplifier power.

My guess is that the front speakers are more efficient that the rears......or he is just old and deaf.

NP993

Okay, I'm reviving this thread. I've given this whole problem a month-and-a-half-long rest and am ready to tackle it.

I'm not looking to make any great discoveries about 993 hi-fi audio systems, and I'm not an audio guru. I just want the rear speakers to work. The fronts are 2-ways and work great. The rears are 3-ways and are barely audible.

Is there any reason I can't do the following:

1) Remove passenger seat.
2) Remove amp
3) Go to Best Buy and purchase new, similar-sized amp
4) Install new amp, plug speakers into it
5) Enjoy four fully-functioning speakers

Any reason why this won't work? Does it matter that the fronts are 2-way and the rears are 3-way?

Fronts: http://www.amazon.com/Pioneer-TS-G13...9785823&sr=1-1

Rears: http://www.amazon.com/Kenwood-KFC-10.../dp/B001Q9ER9Y

Kika

you can insert step 2.5 where you take the removed amp to Best Buy, and have them test it on the bench. If your suspicion is right, the rear channels may be blown. Do you know if it has gain settings? It could also be that the gain is turned all the way down for the rear speakers.
Yes, your approach is good, and should work
Does not matter that fronts are 2-way and rears are 3 way.
IMHO, 3 ways in the rear is overkill, as rear is just for fill.

NP993

Thanks Kika.

Any idea what one does about the factory stereo connections, versus the connections one would have to use for an aftermarket amp? Sounds like a fairly serious rewiring job.

bart1

I was gonna point out that I think getting power to the amp might be a bit involved.

Kika

There are a few ways you can go about re-wiring. One is to purchase a wiring harness that makes all the right adaptions for you. I have never done this, but there are probably kits that will work. The tricky part is finding the right one that makes all the right connections.
OR you could wire it up yourself, making all the connections point to point. It is not terribly complicated, more of a book keeping job than anything else. Either you could tackle the job yourself, or take it to a competent installer, there are many around. Whether you do it, or someone else does, make sure all the connections are soldered and covered with shrink wrap.

Since you already had an amp under the seat, ALL of the wiring should be there, including power. The Nokia probably used a pre-made harness that you will need to get a diagram for. Use tape and label all the wires, so you know what they are. If you can double check ground, power and switched power (to turn on the amp) with a Volt meter, even better.

What I do not know is how much current the Nokia amp used, I am assuming it probably was NOT a high power amp, maybe 20 watts RMS per channel or less. As such, the power wire is probably on the small side if you replace with a higher power amp, say something in the 50W/channel or higher realm. so as suggested above, you may have to run a power wire, which is kind of a PITA.

Keep in mind that not all power ratings are equal, this is one of those marketing tricks that companies use. Power must be evaluated in conjunction with Total Harmonic Distortion, or THD, measured in %. For example, a company can rate their amp at 100Watts/channel with a THD of 10%, sure it has "power" but it will sound like complete trash, OTOH, 20Watts at 0.00001% will sound "clean" I believe this is what we call "Caveat Emptor" or something like that....

so while I have taken a detour down another path, I suggest you stay with name brand amplifiers, vice the ones that have high power ratings that are sold at Pep Boys. This is one of those things where the slippery slope applies. You get what you pay for, which doesn't mean you have to pay excessive amounts of money, but you will have to spend more than $100 for even a decent small amp.

Amplifiers that fit into a good mid range category in my mind are brands like Sony & Alpine, both also carry high end lines that are quite good as well.

I have had Precision Power Amps, and really liked them. Currently I am using a Lunar amp that REALLY is nice, but are fairly thick, and probably won't fit under the seat. I used to be a big Rockford Fosgate fan, but they aren't made in the states anymore and have become garbage since they hit the mainstream.
sometimes you can find some of the old US made Fosgate Power Amps on craigs list or ebay, but be careful, those amps are about 20 years old and may or may not have been abused.

I think Alpine makes a line of amps that are "thin"

If you search, there have been plenty of discussion on various amps and speakers in this forum, along with some really nice installs.

Good luck.

Kika

This is not to imply or suggest Best Buy install ANYTHING, I wouldn't let those guys near my 993, or any other of my cars for that matter. But they are available and should have the set up to bench test things, I know the one by my house does. They charged me like $20 to test some used amps I acquired.

Better yet, if there is an electronics store in your area, they may be willing to hook it up and test it too.

Noah, Where are you located, I would be willing to give you a hand if you want to tackle this yourself, I have most of the electrical equipment.
Anywhere near Los Angeles?