I've followed other threads about replacing stock radios with upgraded systems and I too am replacing my orig. Blau Reno which has a cassette player. Since my cassette collection was aquired mostly in the late 70's early 80's I wanted a unit with an indash CD player. In an attempt to stay somewhat original in appearance I've decided to go with the Blaupunkt Alaska II. I think it will be especially good for the 928 with its angled consoul since it has a high output (read bright) blue lcd for daylight operation but changes automatically to red when you turn the headlights on. It also has red backlighting for the *****, etc.
Anyway, my question is actually about replacing speakers. I have a 91 S4 with a 10 speaker system. The larger (6 inch) rear speakers are both blown. I wanted to replace these but the frame is contoured to fit the curved sidewall of the car. It doesnt look like the actual speaker comes out of this frame. There is also a 4 pin input and output jack for speaker wires which look integral to the speaker. Has anyone replaced these speakers and what did you use? I looked at the Blau website and don't see anything that resembles these. I hate to think what Porsche would want for these. Can anyone help? <img src="confused.gif" border="0">

 

Chris,
Those 6" speakers are 2 ohm and not standard 4 ohm speakers.
I replaces mine with a set of 4 ohm and now have very little bass. Going to add another amp in the future.
To install the speakers I actually took a dremmel and cut the old speaker out of the holder. I then mounted the new speaker into the old holder with 4 screws. Then just remounted. Looks stock except for the sound

 

This comes up periodically, and a search of the archives will get you several threads on this subject.

Short answer: You are screwed.

The large speakers in the ten-speaker system are built into the housings. This can be fixed - you can use a Dremel or similar tool to cut the speakers from the housing, then glue replacement speakers into the housings.

Problem is that the sound will be lousy if you continue to use the stock six-channel amp. The original large speakers are two-ohm voice coils, while the other eight (and virtually all replacement speakers) are four-ohm voice coils. This means that if you replace the original two-ohm speakers with four-ohm speakers, the volume from the two large speakers - all of the bass and most of the midrange - will be half the volume that it needs to be.

Only real answers:
Keep the two-ohm large speakers.
Replace the six-channel amp and rewire the speakers.

 

Never one to disagree with Wally but ....

I managed to get 4Ohm speakers to work OK, I went for the most sensitive speakers I could find. Its been a while but I think they were 94dB or so.

There are lots of reasons why the sensitivity varies in speakers but if you are using the stock amp it probably isn't going to worry you too much.

Anyway I ended up with more Bass (what little there is off it) than I had before.

As Wally has posted before the Amp has a low pass filter on the 'woofer' outputs which cuts off at about 1.5KHz. As your new speakers are likely to be of the full range variety they are throttled.

To get the full range you can bypass the amp for the rear 6.5" speakers and drive direct from the head unit.

Cheers

Chris