Amp problem: 1 RCA plugged in sounding louder than both of them plugged in

[Imtjnotu 5,000+ posts]

change out the rca's and see if that helps if not ur gonna need to change the LOC for a new one......and if all else fails get an rca y adapter for the rcas and just run the L on it split.....

it will be mono but better then nothing

 

[mexiken 10+ year member]

well if the rca was truly "dead" you would get no sound. have you tried different RCA's. also playing with the LOC gain is just as bad as turning up the amp gain. neither of them is a volume know.
try a different set of rca's "preferably new", let us know what happens. if all goes well, set your **** gains CORRECTLY and leave them there for eternity, i know its amusing to hear it get louder but it's also not fun watching your voice coils smoking as your subs burn to the ground

The RCA cables itself are not dead. Either plug (attached to cable) will work on the black female plug of the LOC. However, NEITHER cable works on the red LOC female plug. As in, when plugged into the red female on the LOC and to either female on the amp, I get NO SOUND, AT ALL, to my subs. Moving to black female on the LOC, and everything works fine, however, as I described, when plugging BOTH males of the RCA cable to the females on the LOC AND the amp, I get LESS sound then just unplugging the red one on the amp (and LOC, if I choose)

I will try with another set of RCA's, but I'm pretty convinced its my LOC. If it wasn't, one side of the RCA cable would work with red, but neither do.

How do I set my gains "correctly" ???? Is that done with a DMM mentioned earlier ????

 

[mexiken 10+ year member]

change out the rca's and see if that helps if not ur gonna need to change the LOC for a new one......and if all else fails get an rca y adapter for the rcas and just run the L on it split.....
it will be mono but better then nothing

I will do that thanks. Like I mentioned earlier, I tried both sides of the cable on the same female and nothing, no sound, so its probably the LOC, especially since I turned it a bit to see what was up and that gain control made NO difference in the sound of the subs.

I plugged both in for now and turned the gain up a bit on the LOC and down on the amp (the LOC was pretty low, about 40%, I turned it up to 60) and the amp to about 3/4. The cone isn't moving very much, even at 75% volume at the head unit. It sounds pretty weak. Definitely weaker than my old Kenwood amp. I'm thinking maybe that short that took my amp also took my LOC.

But its still odd that unplugging the RCA thats connected to the dead female on the LOC would INCREASE my sound. I would think it wouldn't change.

 

[I Like Waffle]

Ive seen this problem several times. You probably have one sub wired backwards to the amp, and when you plug in the left (or right) side RCA, the other speaker plays reverse of what the other does, basically cancelling each other out. Reverse the wires on one speaker then plug both the RCAs in and see.

 

[mexiken 10+ year member]

Ive seen this problem several times. You probably have one sub wired backwards to the amp, and when you plug in the left (or right) side RCA, the other speaker plays reverse of what the other does, basically cancelling each other out. Reverse the wires on one speaker then plug both the RCAs in and see.

This requires pulling the subs from the box I assume to rewire them ???? And does this explain why with only one RCA plugged to the amp it sounds louder ???? Not being sarcastic, just asking. I like to know why problems exist.

 

[keep_hope_alive Premium Member]

The Op has done a great job of explaining his problem. We aren't doing him much of a service so far.

The amp is a 2 channel. First question should have been how it is wired to both subs, stereo or bridged? A diagram of exactly how it is wired will help

The RCA's are probably fine based on the OP's tests. If he can get either to work, they are ok.

The LOC wiring to the vehicle wasn't clearly defined. Which speaker wires? Rear? Verify those connections, even swap them to test both channels of the LOC.

Many Honda's have Active Noise Canceling. This wrecks havoc when you add subs. Verify if you have an ANC system and bypass/defeat it if you do.

I too have seen this problem before. Usually is the result of phase/signal polarity. If it was louder with either left or right RCA, I would suspect sub wiring. If the right doesn't work then it seems to be before the amp and the right RCA is pulling the signal down. Maybe the right LOC input is reverse polarity.

 

[jco1385 5,000+ posts]

i bet you got one set of speaker wires backwards on the LOC //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[keep_hope_alive Premium Member]

DOH. Just read the manual.

Amp has high level inputs. LOC isn't necessary

When in BTL or Bridged mode, only the Left RCA input is used.

 

[I Like Waffle]

take the subs out and check the wiring and make sure the ++ and -- are wired together to the terminal. But first just swap the wires on the outside terminal or at the amp on one sub, AKA reverse the pos and neg ONLY FOR ONE SPEAKER. See what that gets you. Sounds to me like one is wired out of phase, then when you plug the RCA in, its sending a signal to that sub, being that the amp is a 2 channel and has a left and right channel. When the other sub gets a signal its moving the opposite of the other one, so theyre basically fighting each other.

Really the best thing for you to do in your situation, is wire the coils in series and bridge the amp so the same signal is distributed.

 

[keep_hope_alive Premium Member]

http://Http://www.docs.Sony.com/release/XMGTX1852_EN_FR_ES.PDF

 

[keep_hope_alive Premium Member]

Never mind, the amp should sum the left and right inputs based on Input Connection A and speaker wiring 2. I suspect the problem is signal polarity or phase before the amp. But the amp will work in bridged mode with only the Left input, specifically labeled BTL.

But you could also have a wiring mixup on the subs. But if the other amp ran them no problem, then you'd think the sub wiring was fine,

Pics and diagrams and well get you sorted out.

 

[mexiken 10+ year member]

The Op has done a great job of explaining his problem. We aren't doing him much of a service so far.

The amp is a 2 channel. First question should have been how it is wired to both subs, stereo or bridged? A diagram of exactly how it is wired will help

The RCA's are probably fine based on the OP's tests. If he can get either to work, they are ok.

The LOC wiring to the vehicle wasn't clearly defined. Which speaker wires? Rear? Verify those connections, even swap them to test both channels of the LOC.

Many Honda's have Active Noise Canceling. This wrecks havoc when you add subs. Verify if you have an ANC system and bypass/defeat it if you do.

I too have seen this problem before. Usually is the result of phase/signal polarity. If it was louder with either left or right RCA, I would suspect sub wiring. If the right doesn't work then it seems to be before the amp and the right RCA is pulling the signal down. Maybe the right LOC input is reverse polarity.

I've never had to draw any sort of diagrams, and I don't have a scanner, so I suppose I'll have to take pics. Here is what I have hooked to the amp (which is screwed into the sub box):

The speaker wires are hooked from the box to the amp.

The Power wire is hooked straight from batt (which an inline fuse on it) to the power terminal on amp.

Ground is running from metal in trunk to ground on amp.

Remote lead is running to my fuse box under my dash I believe, hooked to an acc fuse.

The LOC is tapped off the right rear 6x9. It has the 2 females (one of which doesn't seem to work, even by itself, not when BOTH are plugged in on both ends) that I have the accompanying RCA cable plugged into that are plugged into the line in on the amp.

I assume its stereo ????

I don't believe I have any kind of ANC. I've had subs in this car for 5 years, and only recently noticed that it does this. But again, I've never really looked or checked because I've had more than enough power coming from my old Kenwood. In fact, i'll post a picture of where I had my Kenwood amp set on the gain.

It seems kind of how you describe, as though that right LOC RCA when plugged into both LOC and amp BRINGS DOWN my signal. Its stronger if I just leave that "dead" one unplugged at the amp. But it sounds kind of muddy, its not as clean.

 

[mexiken 10+ year member]

i bet you got one set of speaker wires backwards on the LOC //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

Maybe. I didn't install the LOC, it was installed in 2006 when I got the car brand new. I never tested/noticed it before because like I've stated, my Kenwood hit harder than I needed at a little more than half the moveable knob of the gain (which yes, I know is not volume). It just hit hard since I got it and the only times I ever moved it was down in winter because it was just too much and made my plastic rattle (another long story) and then turned it back to its original spot in summer time. Thats it.

My XM-GTX1852 however, doesn't respond with the same output at the same level on the gain. Nowhere near. So its kind of how I stumbled onto the whole, 1 RCA sounds louder than 2 dilemma.

 

[mexiken 10+ year member]

DOH. Just read the manual.
Amp has high level inputs. LOC isn't necessary

When in BTL or Bridged mode, only the Left RCA input is used.

LOC was how it was installed. I dunno, thats just what they told me I needed. Cost me 50 for LOC box and to move wiring from Chevelle to Honda so I didn't complain too much. Had I known my head unit had those inputs, I would have done that. Lesson learned.

 

[mexiken 10+ year member]

Never mind, the amp should sum the left and right inputs based on Input Connection A and speaker wiring 2. I suspect the problem is signal polarity or phase before the amp. But the amp will work in bridged mode with only the Left input, specifically labeled BTL.
But you could also have a wiring mixup on the subs. But if the other amp ran them no problem, then you'd think the sub wiring was fine,

Pics and diagrams and well get you sorted out.

I have input Connection A but I DON'T have Speaker wiring 2. I have speaker wiring 1. I have a set of pos and neg for one woofer, and another set for the other, so 2 sets of wires coming out of opposite sides of the box both plugged into the 4 different speaker terminals on the amp.

I will post pics on Sunday when I have the day off. I will take the car to my bro's since hes got a power drill and I can get the subs off. If someone can shoot me what I'm SUPPOSED to be wired with I can compare and adjust, and I will of course post before and after pics.