Stereo speaker wiring question.

[Alaskan Itasca]

I decided to remove the previously installed non working cassette stereo, to install a new modern unit. I found a spade on the fuse panel with constant power to wire up the power so no problems there, I had to modify the hole a bit and drill out some rivets since old stereos are smaller than modern single DIN stereos.

The problem I'm having is the original stereo is 2 channel and the new one is of course 4 channell. The RV (a 78 Itasca) has 4 speakers 2 in the front and two in the bedroom. They all seem to be wired together if I wire up the front left speaker both back speakers also work, same goes if I wire up the front right speaker. Needless to say this is not ideal to have decent sound, and I don't have the ability to fade the music away from the back if someone is trying to sleep back there. I can't seem to figure out where the rear speaker wires go and and I can't find where those wires must splice into the front speaker wires. I really dread the the thought of running new wires  27 feet to the back of this thing. 

[ClydesdaleKevin]

Your 78 Itasca should have a knob in the back that allows you to shut off the sound to the rear speakers...on our old 77, the black knob was located in the back left (driver's side) corner, right next to one of the reading lights, under the cabinet.

Ours wasn't labeled, so it took me a while to figure out what that little black knob did.

I'm not sure about the wiring though.  We don't listen to music all that often so we never really thought about the sound quality.

Kev

[Alaskan Itasca]

I'll have to look for this, I haven't noticed any knobs in the back, but I also haven't been looking for one either.

The quality of the music goes down(and the volume is much lower when music becomes distorted) when you start splitting the power out to multiple speakers on the same output, although the output on one channel of a modern stereo is more than the output power of both channels on the original. I can live with being setup on two channels if the back speakers can be turned off from the back. Then I'll be able to figure out how to add a couple more speakers up front.....

[Alaskan Itasca]

I don't have a fader knob in the back near the speakers or the lights under the cabinet, I may just wire in some speakers up front and then I'll be able to fade the back speakers out if needed, or 'll just have to disconnect the speakers so they don't work at all in the back.

[ClydesdaleKevin]

There should be a switch or a knob to shut off the rear speakers somewhere...most of them have one just so you can select between front or rear.  On our current motorhome, its just a toggle switch that looks just like all the light switches.

Our 77 Itasca had it where I already told you.

And our 72 had one up near the front speakers, but it was a brown plastic knob.

Kev

[Froggy1936]

Hi. On some stereos you can pull out or push in on volumn knob for fadeing  Frank

[Alaskan Itasca]

I can't use the stereo to fade since the front and rear channels are wired together, so if I fade the speakers I have no speakers at all.

My 78 has two speakers in the bottom of the cabinet over the windshield, and two speakers in the back on the bottom of the rear window cabinet. The only switch I have I can't figure out what it does is a light switch on the cabinet with the sink. I'm assuming it runs the lights along the floor, but since those don't work I can't confirm what it does....I'll keep looking for odd switches or toggles mounted in the thing but I so far haven't found any.

[jkilbert]

it sounds like yours is wired like my brave. you probably have 6 speaker wires under the dash. rear, left front and right front. and if it's like mine they're probably all white. all i can suggest is to start with the old trial and error until you figure which pairs go to which speakers. my rear wires ran up the left side of my coach. under the dinette and behind the bathroom. i used the old wire like a fish tape to pull 2 new wires (2 conductor speaker wire) to the back.

[DaveVA78Chieftain]

A helpful device for things like this



http://www.harborfreight.com/cable-tracker-94181.html

Dave

[Alaskan Itasca]

I just ordered the cable tracker, I have a feeling that will be a handy tool in this old rig.

On the wiring only four wires(for two chanels) come off the stereo as far as i can trace with my arm in the dash, I even removed the cluster to make tracing easier, So it must splice in in the wall some where. Thanks for the advice, now I'll wait for the tool to show up and tackle figuring out where it runs. I do think it does run on the left side as well since the front speakers run in from the left side.

[Alaskan Itasca]

I have been figuring out this problem, I connected the cable tracker to the wires and figured out where the speaker wires are under the dash, I now see how the factory spliced the left speakers together and the right speakers together. I also see what a PO has done to screw that up. For some reason he put finishing nails through all the wire sheaths and essientially shorted them all together making the signal from one channel go to all 4 speakers. I'm guessing the original radio partially failed and rather than replacing it he just made them all work off of one channel. So ow ill haveto cut everything off past the factoy plugs an wire in new speaker wire to the head unit. This will reove the finishing nail mod and the spliced together factoy harness for a 2 channel stereo.

[Oz]

Many problems (sometimes very dangerous ones) stem from PO electrical hack jobs.  Although this one is a PITA, let's hope you don't find anything similar under the dash or elsewhere.  You may want to take a good look at your wiring to make certain.

[Alaskan Itasca]

I got thefront speakers wired up and working. Now I need to get some more speaker wire and new rear speakers. Then i have to modify the hole in the plastic since modern stereos are a hair longer and wider than the old stereo.