Replace CDR23 and Bose MOST amplifier

[Bill Cage]

The car is a 2004, Boxster S - 986, with "Bose High End Sound Package" option. This Bose system has the CDR23 head unit and an amp in the front trunk. There are left and right speakers in the dash, the doors and in the rear mounted speaker box. The rear mounted speaker box has two small speakers on the left and right and a large port in the center.

I am a persistent person, but I am finally having to reach out for help. After several months of off and on searching for information, I finally decided to pull the trigger and replace the head unit in the Boxster. From reading an unbelievable number of posts on this and other forums, I was convinced that the best course of action was to circumvent the MOST system and replace the head unit and amp together. Contrary to most advice, I plan to keep the original speakers (at least initially).

Wiring is the challenge. My thoughts were that I would replace the pre-amp wiring with new since that is where the MOST system is in play so this was a no brainer. I purchased a wiring harness from Crutchfield to keep the original harness intact. While it did allow me to keep the harness, it only mated to 3 wires (and Crutchfield had two of those wired incorrectly). Luckily searching this forum and using my multimeter, I was able to figure out what was needed for the head unit.

Pulling the pre-amp wiring from the new head to the front trunk turned out to be easier than I was expecting and wiring the amp for power is a breeze since it is almost on top of the battery.

Now, speakers. I thought this was overly complicated from the post and some extensive DIY posts that I read, but I pushed on. I hunted for days on end to find a wiring diagram that matched what I was finding in person and have still not found it; I have looked at numerous ones, but none are actually like mine. I have come to appreciate that Porsche has many ways to wire these things and it is almost like everyone is unique.

Not having a wiring diagram that worked, it was pretty easy to separate the speaker wires from the others on the wiring harness that connected to the original amplifier. My plan was simple, put an audio source on each of these and map where sound comes out. The first unusual thing that I encountered was that there were only 5 speaker wiring pairs. I expected 6.

As it turned out, two pair mated to the left / right dash speakers; two pair mated to the door subs; and the last pair drove both speakers behind the seats. This is odd and made me wonder if there is actually a subwoofer back there, especially with the large center mounted port and the fact that the visible speakers are very small.

Has anyone else dealt with this configuration? Does anyone have a wiring diagram that matches this? The amp is marked as a Bose 996.645.333.05. I have searched for information without any luck. The pins are such that it appears to be a 5 way amp, but I would typically think that the single would drive a sub, but all the information that I have seen says that the door speakers are actually subs.

My thoughts right now are to continue to treat the door speakers as subs. I am going to wire them in serial to get the impedance up. My understanding is that they are 2 ohms individually. I will drive the two dash speakers normally and then drive the rear speakers as a mono channel.

Any experience and/or advice out there?

Thanks

[Loren]

:welcome:

Yes, the BOSE option has a subwoofer.

[Bill Cage]

Thanks! This is the diagram I have been looking for. Do you happen to know the speaker impedances for each speaker?My new amp is a five way. My current thoughts are to drive the dash speakers with two; the door speakers with two; and the sub with the sub out. The question then is what to do with the rear speakers. It looks like they are driven in a mono configuration stock,so my thoughts are to drive them with the doors. Has anyone done similar? I assume that I could get into the box and separate the speakers and run another speaker wire to be able to drive these independent of each other. I could then wire them in concert with the doors.Any thoughts out there on this approach? Anyone else gone through this and have other suggestions?

[Loren]

Someone with the system will have to give you the speaker impedances - I do have access to one now.

Lots of options - do a search to see what others have done.

[gt3m]

How about use some crossovers to drive the dash speakers ad the door speakers with 2 channels? Then use the other 2 channels to drive the rear speakers.

[Nimbus117]

I have the Pioneer 940BT head unit. I run the front and rear speakers off the head unit amp and the subs in the doors off a 2 channel Alpine amp from the RCA head unit output. Located the Alpine where the Porsche offering used to live.

Also fitted a reverse camera, the Porsche wiring is a bit strange (I connected the feed to the reverse lights) but it means I can select reverse view manually when going forward. By rights, the camera should only be live when the reverse lights are on.

[mdbraun]

Bill,i have a 2005 Boxster S. My Bose system is similar to your.except i also have 3 1/2 mids in doors above subs.The box in back has the 2 small speakers behind headrest.the box also has 2 6in. subs pointing down.also has its own amp in the box.System doesnt make sense with subs in doors and behind seat. Got rid of all of it.Now have Alpine 6 1/2in.screen head unit.With a Clarion EQ in glovebox.Out to Xfinity an Alpine Amps. I put slim 8in. Rockford Fosgate subs in doors.Also took subs an amp out of box.An put in Morels facing up(modified box as needed).In my searches,ive been trying to find out if theres a crossover between dash tweets an door mids or if their just spliced together? Cause theres only 2 sets of wires at amp(instead of 4 sets).Just like yourself lots of research with limited answers.