Feedback/Static JL Audio system

Hello,

Recently installed a new system in my 2014 DC Entune non-JBL. JL Audio C2, 10W1v3, pioneer 5 channel, and LC2i. Tapped into factory front speaker wires right at head unit, ran them into LC2i, to amp, to speakers.

With all the gains set to 0 on the LC2i, I'm getting a static feedback in the tweeters at 0 volume, and a high pitched buzzing when music is played. The buzzing continues for 5-7 seconds after volume is turned to 0, then cuts off. Buzzing/feedback increases with volume and turning the gain up on the LC2i. Has anyone experienced anything like this?

Got in touch with Audio control and they gave 2 suggestions; disconnected inputs from LC2i and no buzzing, so it's not the unit itself. AC rep suggested putting a resistor between head unit and LC2i to simulate a speaker being there, so wired the factory speaker in between them and it did not change anything. I removed the LC2i and ran speaker level inputs to the amp, and the feedback was still there but the buzzing was gone.

Looking for similar experiences or audio wizard's input on this, any input is greatly appreciated as I'm stumped at this point!

 

Does the sound increase with engine RPM?

 

No, I read about the alternator whine and it does not increase with RPM. Going to go back through it today and reground everything just to be sure, thanks for the suggestion though!

 

Subbed for answers, I have a similar setup and similar issue. Left speakers, front and back, both have a buzzing sound that is louder upon start up, like something is warming up. Fades after a bit to a lower pitched buzzing that is present at all times, even with volume turned down, new frequency comes in when headlights turn on. Buzzing/humming doesn't increase or decrease with volume, stays pretty consistent and is drowned out easily by the music when turned up.

Rockford Fostage R1675 component front and rear door speakers, OEM entune non-JBL headunit, Kenwood Excelon KFC-XW1000F, LC6i and a Pioneer GM-D9705 5 channel amp

 

How do you have your remote turn on set?

 

Amp's remote turn on is from the LC2i, I believe the LC2i picks it up from the speaker input

 

hmm.. When you tapped into the harness behind the dash for speaker level input, how do you have the wires run from your amp to the speakers. Did you run new wires to each one, or did you put them back into the factory harness?

I was thinking maybe your pushing amp power back into the headunit if you didnt go from headunit to lc2 to amp, new speaker wires to speakers or make a t-harness to tap into the factory wires but isolating them from the amp.

 

When you turn your volume to zero, does the buzzing continue for a few seconds, then shut off? I'm almost positive its something to do with my head unit, when I turn the radio off (click in the volume knob) it will instantly kill the buzz. Will chassis ground head unit in an hour or two and report back

 

Turning off the radio turns off your amps. turning to 0 volume will also turn off a lc2 since its not sensing any signal so it thinks the radio is off.

 

I didn't re-use any factory wiring, just tapped into the harness and ran new wires from head unit -> LC2i -> amp -> speakers, all with new speaker wire

 

Do you have a multimeter? I would check to see if any of your wires are grounding out. pull the wires off the amp and check to see if any of them are grounded (multimeter from 1 wire to ground).

BTW, I dont know whats wrong with your system, just sending out general trouble shooting tests you can do.

 

Ok, will the LC2i stay on despite no signal if I have constant power to it? I have a power wire ran directly from the battery to it, and it's chassis grounded as well. I'm pretty sure I saw that in one of their diagrams

 

The lc2 will have the normal power and ground, but it will not turn on until it either senses signal from the high level inputs (speaker wires going in) or if you connect the "remote" wire to a keyed on (usually a blue wire on aftermarket headunits)

 

These are all good suggestions, thanks for the help! I do have a multimeter, are you saying to test the input RCA's to the amp or the amp's speaker output wires? Or the input wires to the LC2i

 

The amps output, take the wires that are connected to the speakers and check each one. You can do it right from the amp side so you dont have to pull all the panels off again. Just disconnect the speaker wires from the amp and check them.

 

Sounds like a plan, I'll check that before I start pulling my dash apart! Thanks again

 

Just re-read your setup, and I have the exact same amp. I'll do some research and see if anyone else has had this issue with the Entune head unit and the GM-9705

 

What are you grounding the amp to presently?

 

Strangely no. The buzzing persists after I turn my volume down to zero, or even turn off/hard reset the head unit. Taking it in to the guys who installed it tomorrow or Friday, they seem to think it might be a bad LC6i and are going to replace it for free. They had already replaced the amp free thinking that might have been the cause as well, so we’re slowly narrowing down the options.

 

Amp is grounded to a bolt under the center console, on the transmission tunnel. Sanded to bare metal