[idosubaru]

Act like you're talking to a 4th grader, I'm not fluent in "audio"!
02 OBW H6 VDC, non-working McIntosh system when I got it. swapped in a WRX 6 disc changer (plug and play) but I only get sound from the front speakers.

I swapped rear speakers, amp, and multiple head units, with no change or sound from the rear.

Driveby suggests rear McIntosh speakers should work with other plug and play Subaru stereos...I thought I read somewhere that they don't, but I couldn't find anything to that effect tonight.

Simplest fix seems like running new wire to the rear speakers....but:

1. how do i find the source wires?
2. Or how do I confirm there is output from the H/U or amp?

My main confusion is:

Folks were saying to run speaker inputs from the headunit....seems like it would come from the amp...like this:
headunit - amp - speaker

link so i can find it later:
http://www.subaruoutback.org/forums/80-electrical-electronics/25135-mcintosh-system-question-does-require-amp-work.html#post240741

 

[idosubaru]

Also driveby mentions "speaker joint connectors" and "running in parallel with the amp"......I have no idea what that means?

 

[Vernon]

I have had some adventures with the McIntosh sound system. When I bought the car the amp had been bypassed because the headunit had been replaced with an aftermarket unit. How are you connecting the WRX unit to your front speakers? I looked at some pictures of the back and I don't see how it could be plug and play with the McIntosh system. They all have the Subaru harness but with our cars all of the audio normally runs through a separate round 13-PIN cable from the head unit to the amp, which then sends it out to the tweeters, door speakers, and subwoofer from another Subaru-style harness.

 

[idosubaru]

McIntosh unit has the same plug as all other Impreza/Legacy stereos from like 1990 - 2004. So I simply plugged in the WRX in dash changer and it works fine (except no rear speakers).

I'm unclear of the path the signal takes...but maybe all but a few (the rear?) pin outs are the same so that's why it works if you swap them?

But you're saying the output to the speakers is through the round cable (which I saw)...so I guess I need to verify that....if that's the case then something is certainly wonky...

Be nice if it was a wiring issue - maybe these 3 McIntosh units I have aren't all junk. LOL

Where to find the wiring diagrams for these?

 

[Vernon]

Here's one for the amp but I don't know how it compares to the WRX unit.

McIntosh EF-1080I Information My Blog

 

[Vernon]

I know on the stock McIntosh the round 13-PIN plug is pre-amp audio out - not sure if it serves the same function on other Subaru radios.

 

[idosubaru]

I know on the stock McIntosh the round 13-PIN plug is pre-amp audio out - not sure if it serves the same function on other Subaru radios.

Okay, cool, that's a good start, i'll check that diagram out tomorrow. The WRX changer i'm not worried about - that's the same as every subaru 1990 - 2004 so those pins will be easy to find.

so what does the unit use the "normal" Subaru plug for....power, etc?
The McIntosh has 13 physical pins in the rectagular connection, just like other Subaru stereo's....though it doesn't mean they're all used internally...?

Maybe the rectangular plug also simply has front door wiring already installed but not rears...or that's impossible?

should be obvious if someone messed with it, i would think?

 

[Vernon]

so what does the unit use the "normal" Subaru plug for....power, etc?
The McIntosh has 13 physical pins in the rectagular connection, just like other Subaru stereo's....though it doesn't mean they're all used internally...?

I believe this is correct - if I recall the McIntosh headunit only uses the Subaru connector at the head unit for power, illumination control, and antenna booster power.

Maybe the rectangular plug also simply has front door wiring already installed but not rears...or that's impossible?

Yes this is definitely possible. I've never tried to hook up another Subaru radio but it may be the front speakers are wired to that harness as well as the one that plugs in to the amp under the seat. I think this is what driveby was talking about when he said in parallel with the amp - that at least some of the speakers were wired to receive a signal from either the amp or the regular harness in the dash.

should be obvious if someone messed with it, i would think?

I hope so! It would be trickier for the speakers since you will have to pull the door panel off, but it's pretty easy to tell looking at the amp if things have been rewired down there.

If you aren't using the original head unit, one option is to make a bypass cable to connect the speaker wires from the headunit with the Subaru plug that would be otherwise connected to the amp. The disadvantage of this is you won't get any sound to the subwoofer in the back. This is why I ended up ditching the aftermarket unit and putting another Subaru McIntosh radio from eBay back in there.

I have an extra McIntosh unit that I need to test this weekend before selling it so I'll be messing around in the dash and could get some pictures/video of the stock configuration if you think that would help at all.

 

[lashlee]

I don't think it lasted into the 2000's but older subies were wired up as "common ground" and make it difficult to add an aftermarket radio. Common ground is bascially a three wire setup for each side (front and back) with two positive wires, one going to each speaker and a common ground wire that went to both speakers. When I would do an install I would use the common wiring for the rears and run new wire for the fronts due to the proximity and length of wire. I know you are dealing with a Subaru unit but a newer unit might not be set up the same way but I would see if you disconnect the front speakers (at the speaker or radio) and see if the rears begin to play.

Have you used a meter to verify that the speakers are good (measure the terminals with the meter set to measure ohms and it should be 3.6 - 4.8) or simply pop the speakers with a battery to see if they actually move. There is a chance that the drivers appear fine but the voice coil may be fried and is buried inside the motor structure.

 

[plain OM]

grossgary:

Here's the wiring diagram for the 02 audio system. The first two pages are for the regular head unit, and the last three pages are for the McIntosh.

Looking at the regular radio pages, we see that the speakers are connected through connector i26. In the McIntosh setup, page 3, these same connection terminals are "open". Instead, the audio from the head unit goes out through the DIN cable (see page 3) to the underseat power amplifier. The speakers are connected to outputs from the amplifier, via harness connector R110.

With the McIntosh wiring in the car, the audio has to go from the radio to the amplifier and then to the speakers -- there's no direct connection from the radio to the speakers. At least not according to the diagrams.

I understand from the first post that you have substituted the rear speakers with known good ones, have tried different known good head units (compatible with the McIntosh, i.e., work with the DIN cable), and have tried a different known working McIntosh power amplifier. That seems to eliminate the main "hardware". The question, then, is whether rear speaker audio signal is going from the radio to the amplifier through the DIN cable. (There's four separate audio channels for each of the four door speakers, as noted in the block diagram in McIntosh EF-1080I Information My Blog.)

Checking for audio at the power amplifier end of the DIN cable needs something like an oscilloscope. But if you can access the DIN cable connectors at both ends (radio and amplifier), at least the continuity through the cable can be checked. The linked thread shows the pin numbers of the DIN connectors, so it should be possible to check for continuity between matching pins.

Other connections to the amplifier, such as power, ground etc are common to all the channels, so they should be okay. (Volume, balance etc are all in the head unit.)

This all assumes that the wiring hasn't been modified from the original (something you alluded to earlier). If it has, then "all bets are off", as there's no telling what might have been done.

 

[idosubaru]

As a follow up - I did get the McIntosh unit working - I'm not sure what finally did the trick but I think it may have been a replacement used amp I got was also bad.