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Discussion Starter #1
hello. Im having some noise issues with my 2011 mustang audio system. I have installed an aftermarket amp/speakers and subs. Im using an audiocontrol LC2i LOC and getting the signal from the front speaker wires coming out of the radio harness. Using a kicker IX 1000.5 amp. Here is the issue. I have a high pitched noise coming from the speakers. It only happens when the car is on and does not fluctuate depending on engine rpm. I've check and rechecked all my grounds and all is good. even grounded straight to battery just to be sure. I even installed a ground loop isolator with no luck. I had a spare oem radio which I switched out and problem is still there so it cant be the headunit. Gain on the amp is a little less than half way and I did notice that if I turn the gain to about 1/4 the noise goes away but at that point I have to max out my volume to get a somewhat decent loudness. What could the problem be?? any help is appreciated.
 

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I say try removing the LC2i and running the signal straight into the amp. There's really no need for the LC2i since your amp accepts Hi Level input. You just need to get some High Level to RCA adapters.
 

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Discussion Starter #3
I removed the lc2i and the problem is still there. If I disconnect the rca from the amp the noise goes away so it has to be somewhere before the amp. Dont know what else to check
 

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Plug an iphone/DAP directly into the amp using an RCA to mini stereo cable. Just because the noise went away when you disconnected the RCA's doesn't automatically mean the noise came from upstream of the amp. By disconnecting the RCA's the amp doesn't have a signal to amplify, so it could easily go silent even if the noise is being caused by the amp. You need to try a different source to know for sure.

What aftermarket head unit are you using? I'm guessing it has RCA outs, so there was no reason to use the Lc2i in the first place, leave that out and troubleshoot. How/where is your amp grounded? A poor ground could cause the equipment to attempt to ground through the RCA's which could cause the problem you're describing.
 

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Discussion Starter #5
I'll try the ipod directly to it and see what happens. I'm using the stock navigation unit which is why I got the lc2i. I've used different grounding points in the trunk. Sanded down to bare metal I even connected it all the way to the battery to make sure and that didnt work.
 

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I'll try the ipod directly to it and see what happens. I'm using the stock navigation unit which is why I got the lc2i. I've used different grounding points in the trunk. Sanded down to bare metal I even connected it all the way to the battery to make sure and that didnt work.
Gotcha, I've not been reading very carefully lately. But, the amp accepts speaker level inputs, then the lc2i shouldn't be necessary at all. Make sure the button on your amp is set to high input level.
 

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Discussion Starter #7
Ok so I went ahead and unplugged the speaker level inputs going from the headunit into the amp. Plugged my phone directly in and turned the car on. The noise went away! I'm thinking maybe the speaker wires coming from the headunit are picking up some kind of noise that's being amplified by the amp? I will once again check behind the radio and see if somehow I missed something that's causing this.
 

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Ok so I went ahead and unplugged the speaker level inputs going from the headunit into the amp. Plugged my phone directly in and turned the car on. The noise went away! I'm thinking maybe the speaker wires coming from the headunit are picking up some kind of noise that's being amplified by the amp? I will once again check behind the radio and see if somehow I missed something that's causing this.
Speaker level signal isn't prone to noise like low level RCA's so I highly doubt it's the wires picking up noise. There could, however be a short. If one of the wires has been pinched, and is grounding out a bit, that could cause noise, but they won't pick up radiated noise like an RCA can. Did you make sure that you set the amp switch to high when using high level inputs, and low when using RCA's?
 

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Discussion Starter #9
Thanks for the info. I'll be taking everything apart later on this week and check all the wiring behind the dash and see If anything back there could've been pinched or loose connection somewhere.
 

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Discussion Starter #10
so I went out and took everything apart and double checked wires and everything seems normal. nothing loose or pinched. If something was shorting out wouldn't it make noise regardless of whether the car was on or not? I only get the noise after turning on the car. once I shut if off it is gone. its a high pitched sound that sounds like when your ears are ringing. if I back the gain on the amp to about a quarter is almost goes away and can only hear if I put my ear by the speaker. Amp is set to receive speaker level inputs.
 

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Discussion Starter #12
It has usb and aux in back in the center console by the arm rest. ill see if I can unplug from there.
 

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Discussion Starter #13
I tried disconnecting the aux and usb and nothing. I'm at a standstill. I've never had a problem like this and its driving me nuts.
 
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