4 Channel Setup acting like 2 Speakers

[czickefoose]

So I'm really hoping some smarter people than me can figure out the issue I am having with my car's speakers and hopefully the issue is a quick fix that I can perform without having to take apart much. I have a medical condition that makes doing a lot of physical stuff difficult, and with this heat, it makes it even more difficult. Anyway, the wiring in the trunk is super easy to get to so hopefully it can be fixed there. The issue took me a while to notice. I had a shop custom install a full on stereo in my Mercury Marauder. It was a full custom job as this car doesn't have a true 2 din stereo, so they did a lot of work on it. They also did some custom work on my door panels with tweeter placement. All in all I'm happy. But I think they did something funky with the wiring. And when I say "think" I mean I know... When I try to balance sound left to right... nothing happens. The sound remains the same. When I fade front to back, it works as normal, but left to right, nothing. So if I go all the way to front left, it sounds as if I only faded to the front. If I go all the way to back right, it sounds as if I faded to the back. There is no balance between left and right. It is like the wired both the front speakers as one speaker and both the back speakers as one. So the four channel set up is wired as a two channel. Now, here's the deal. I have two Rockford Fosgate R400 D amps and one Pioneer D9601 for my sub. The Fosgates are four channel amps that are being bridged as 2 channel to run the fronts and rears, one amp per two speakers. So I really think they did something funky with the wiring that lead to this issue. I am attaching photos of the amp wiring. I wasn't able to get pics of the back of the head unit, sorry. I probably should have though. And what's more, the car is in the shop right now and so I won't be able to look at the head unit until I get it back. But can anyone tell if they think they did something wrong from the photos? The shop that did the work is 3 hours away. My parents used to live in that town and I had them do the work while there for a weekend visit. Well, they moved away and I no longer go there and can't really justify the trip just to have them adjust the wiring. The stereo sounds great, don't get me wrong. But I can't help but to think it would sound better if it were able to play the way it should as a four channel set up. Is there a reason why they would have done this? Is this common practice with people? I wrote the shop and all they said is bring it in and we will look at it... pretty lame to an otherwise good experience. So again, to clarify, the stereo is treating the front speakers as one speaker and will not balance left to right, it plays equal amount of sound from both. The same for the back. I can only fade front to back. This is true for any CD, any bluetooth source or any other audio source, so I know that it is not the sound source. Since the photos I took are too large to post here I am leaving a link to imgur to view them at, sorry. Again the car is at the shop so I can't go retake the photos. Thanks

Car Audio - Album on Imgur

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[BOOMINGRANDPA 5,000+ posts]

sounds like they ran 1 channel to front speakers and 1 to rear., unless rcas are connected wrong somewhere

 

[czickefoose]

I'm super pissed I can't check it right now but I really think you're right. The only answer is there are two rca in the back of the head unit, right? Then at the amp it splits to four. Why would they do that? Is there a sound quality reason for that such as better wattage and better sound response? Sounds unlikely but this place is reputed so I don't know why they would do that. But again, i dont know for sure until I look. If there are all four hookups behind the head unit then I'm clueless. The next question would be... can I remedy this without running new rca cables? Could I just use a splitter at the head unit if that's the issue to get two separate channels without sacarificing sound quality (I'm an audiophile).

 

[dpuc10]

This may not be even close, but on the rear amp flip your RCA so the white is on top and red is on the bottom and see if that fixes anything.

 

[czickefoose]

Well if you're talking about the pioneer amp that is for the sub, not sure if that would help the other speakers as I'm not having any issues with the sub. But I did flip the other rca cables to no avail either.

 

[BOOMINGRANDPA 5,000+ posts]

man i'd go back to shop and make them fix it

 

[czickefoose]

Yeah, no doubt. But they are 3.5 hours away, so I would only be going for them to fix my stereo. It is really hard to justify that trip. I had them do it originally because my parents lived there and I don't have anyone locally that can do it. So seemed like a good idea at the time, see my parents, have a great custom install done... win win... Well, parents moved so that win win is looking like a loose loose now. Anyway, I'll look behind the head unit when I get the car back. What do you think though about splitting it at the head unit if they did in fact only do two channels at the head unit? Would that work, in theory and would the sound quality still be the same? I will get with the shop and let them know how much they screwed up when I figure out what is wrong though, for sure.

 

[czickefoose]

I did find the receipt and see that they used the JL audio 4 channel RCA. This: JL Audio 4Channel Audio Interconnect Cable XMDWHTAIC46

So there should be no issues with the RCA I suppose unless they simply didn't connect all four channels in the back of the head unit. I'll check that when the car gets back.

 

[czickefoose]

So I got the car back and was playing around with the RCAs. And now I'm more perplexed. I balanced to the front left. Playing music, I unplugged the front left from the head unit... no sound. Just like it should. Well, except for pumping bass from my manly subs of course. Plug it back in, sound. Just like it should. So far so good. With both rca in, I balance to the right, no change in sound, both speakers are at the same sound level. Uh, what? I balance to the right, all the way to the right, the left speaker is still playing at the same sound level as the right. See where the issue is? I unplug the right speaker and voila... no sound. I balance to the left, there is sound, like it should be. What is going on here? So, essentially, somewhere along the line, the head unit realizes there is two speakers, but when both rcas are hooked up, the thing gets all confused and plays both speakers as the same.

So I am now wondering, because this is a reconditioned head unit, could the issue be internal to the head unit? Like is it bad or something? Maybe something internal is making it not able to differentiate channels? It is a Pioneer 4100nex. There's no warranty at this point. Anyway, just wondering what you think if you had any thoughts about it at all.. Thanks

 

[Papermaker85 5,000+ posts]

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[czickefoose]

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[BOOMINGRANDPA 5,000+ posts]

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