I was happy to find this thread mainly because I thought the factory had really messed up the wiring on our upgraded audio/video package. This is indeed what has happened.
Fasten your seat belts folks, this is going to be long. Unfortunately, words come easily to me.
The sub-woofer "rumble" that everyone describes matches our experience exactly.
We ordered the remote speakers option.
We also ordered a Sirius satellite radio. We were getting lots of hum when the TV sound was being played through the stereo; same when using the sat radio. We found that the sound for the TV and the Sirius radio would play at the same time. Very confusing. If I unplugged the power from the sat radio the hum went away. Must be an electrical problem, eh? Not! Read on.
What to do? Take it to a dealer and let them turn some 19 year old who cannot find his a-- with both hands in high noon sunlight? Not. I agonized over this for two or three nanoseconds and opened up the portion of the cabinet in the overhead where the stereo is located.
But first I got out all the docs on the radio. The Aux In doc provided the most info. It has a very nice diagram of the auxiliary unit that is used to pump four separate inputs into the stereo. It also helped understand how things were supposed to be wired. I realized the TV and sat radio were using the same Aux In channel for one of these inputs - a big aha.
Back to the opened cabinet.
To say that the wiring I found looked like a rats nest is putting it mildly. I spent a morning sorting it all out just so I could see what was what. The only labeling on any of the cables was on the cables exiting the Sony radio. The good news is that this, coupled with the Aux In wiring diagram was enough to get everything sorted. Every cable now is ID'd with labels from our label maker.
The sat radio and TV conflict was easy to resolve. They had both of them plugged into the CDC2 port selector on the Sony Aux IN unit. I moved the sat radio to the empty jacks for the CDC3 port selector and that problem was solved. Now I can watch the TV and listen to the sat radio without the TV sound in the stereo speakers. No more hum either with the sat radio plugged into the power.
Next, I found the sub woofer jack from the Sony unit to be flopping in the breeze. Huh? If this is the case, what on earth is plugged into the sub woofer?
I went on the internet to see if I could locate some info about the sub woofer. Absolutely no docs on it came with the trailer. Found absolutely nothing on the internet either. I did find others posting on forums looking for the same info.
What made this confusing is that there is a small junction box flopping about with many wires from the stereo unit connected to it. This unit is not from Sony. This box is not from the manufacturer of the sub woofer either. This small adjunct box has two interesting items marked on it. One is a jack labeled sub-woofer with a single wire that I discovered is routed to the sub woofer. This wire is the third wire in the plastic harness that also has the battery and ground wires on it at the sub woofer. This adjunct box also has EXT SPEAKERS labeled with only two wires connected to the line out jack. More on this jack later; back to the sub woofer.
I pulled the sub woofer and saw the connection for the RCA jacks and decided that this had to be the input for the sub woofer; I forget what the jacks on the sub woofer were labeled.
Back to the rats nest of wires. Ultimately I discovered that the factory had connected the sub woofer to the rear speaker output from the stereo unit. I got the wires for this moved and now found I actually had some bass sound emitting from the sub woofer. I used one of the "two into one" splitters the factory had used to connect the TV and sat radio to the same input on the Aux In unit to split the single sub woofer out put from the Sony unit into two for input to the sub woofer - all RCA jacks.
But, this is the weakest sub woofer I have ever heard. Part of the problem is that it is under the sofa at the front of the trailer and the sofa just soaks up the sound. I have both dials on the sub woofer turn up to the most advance position on the rotary switches.
I wrote email to the company that manufactured the junction box with the EXT SPEAKERS and sub woofer wire coming of it to get the definitive info as to which wires are for left/right hot/ground for the speakers. They sent me two PDF files that contain the schematics for the electrical box I have been discussing AND the Speaker Select Switch that is above the stereo AND the following:
"The (2) prints in PDF format should explain the design and function of
the circuit in question. The jack in the face of the switch plate would
not make any sense as to the way it is wired unless you know the history
of the item. I'm not sure who supplied the mono speaker, but the jack is
wired correctly except no ground wire is supplied for its usage at the
time of design. This is because it is a floating ground system and
cannot be directly grounded. The jack was provided for a wireless
headphone system which derived enough of a ground through itself to
function. You could run a separate chassis ground to the jack and use it
for headphones -IF- you isolate the left + and right + by running each
through a 5uf capacitor with the (-) toward the jack and the (+) toward
the 4 pin plug, headphones would work but the speaker never will. If you
don't isolate the positives and IF you use a (-) output from the radio
for ground side, the Radio will typically overheat and destruct. You can
of course use speakers if you observe the (+) & (-) for each pair per
the diagram Ignoring the jack."
Glad I did not do anything to the wiring prior to getting this info! If anyone is interested in this info PM me and I can email them the PDF files; I have received permission from the manufacturer. This also explains why my headphones would not work. Now I can fix this with a bit of electronics and a soldering iron.
I also learned that the Aux In unit that accepts all the sound input was very interesting. It now has input from the TV, the CD changer, the sat radio (all use RCA connectors) and one more input jack. The 4th jack a USB slot for a computer connection. I plugged a USB cable from my laptop into it with the stereo output set to CDC4 (prior to plugging in the cable) and my computer popped up the "Found New Hardware" dialog. I would only do this with a connection to the internet; this way the computer was able to find the appropriate drives on the internet. Walaa. I now have USB speakers. I brought up my MusicMatch and found that it now showed USB speakers in addition to the audio device built into the computer under the Play tab of the Options window. It took MM a long time to come up when this was first done. Patience. I now can play any of my 65 GB of music on my computer through the stereo system in the trailer.
Now that the rear speaker cables from the radio were available I decided to make use of them. I have a small speaker system from Cambridge Soundworks that operates on110V AC or 12V
DC that I have used for 10+ years to play sound from my computer. I installed the cables that will now let me plug it into the rear speaker jacks on the stereo. This will allow us to have surround sound from DVD,s. Cool. I can also use it with the line out jack once I get it rewired, instead of the the built in speakers in the trailer by using the selector switch at the stereo area where the line out jack is to control the trailer speakers and plugging my Cambridge speakers into the line out jack.
FYI, no sound from the stereo rear speaker cables unless there is Dolby sound to be decoded for them as far as I can tell.
Now, having said all this, I continue to get the hum from the sub woofer when a DVD is in the DVD player and the player is not playing. When the DVD is removed I get no hum.
My challenge now is to determine how to route the various cables from the stereo to the areas I want them for use with the computer and the Cambridge speakers. I have not looked at everything in this sub-forum for ideas for routing the cables and am open to ideas and things people have done to solve this issue.
Hope this may be of use to others.