I wish there were installers like you guys in my area! Sadly, after years of taking my cars to this particular place, I've lost faith in them. Come to think of it, they didn't do such a hot job on the last install they did for me either. They finally fixed the problems but I had to take it back 2 or 3 times.

This time they didn't fix it at all and I ended up having to fix it myself. Like I said, it's still not 100% fixed but for all practical purposes it's undetectable.

I'm not really sure what brand the LOC is. I mounted it up under the dash with two-sided tape but if it helps you to know what brand it is, I'll pull it out and check.

As for moving the LOC around while the car was running, that wasn't practical for me to do because the noise was only audible when the car revved at mid to high rpms. And it got louder the harder I would accelerate. For example, if I was parked and just idling and then revved the car, you could hear the noise but it was relatively low. But when I was getting on the expressway and gunned it, the noise would get much louder.

So it would have been hard for me to move the LOC around while I was driving....actually it would have been impossible and I would probably have crashed.

Anyway, I like your idea of how to fix it completely. Can you be a little more detailed about how my wiring would go if I were to follow your suggestion?

The amp only has RCA inputs so how would I run the speaker leads from the head unit to the amp's RCA inputs? And where exactly would the 10 ohm resistor go, and where might I get them?

Man I wish you were local!!!!!!

 

I'd be willing to bet it is using a transformer. I know the kick panel is easiest for the install, but I'd move it to the area behind the speedo or change amps as Kevin suggested.

 

Do you think that the Kenwood amp I posted the link to earlier (http://www.amazon.com/gp/product/B00...sc_act_title_1) would work? Would it just be a simple matter of pulling the RF amp out and putting the kenwood amp in using the wiring that's already there? The noise is pretty much gone after moving the LOC but if the Kenwood is a better amp than the RF and less prone to this type of noise, for the price it might be a good investment to make in the future.

 

We don't run a retail shop. However, an important part of our products is that they are specifically designed for a particular vehicle. They eliminate the kinds of trouble you are having here, without having to have an expert close by.

This would only make sense if the noise is being magnetically induced and load that is inducing the noise was using more current while driving/accelerating. Otherwise the noise would be constant and vary only with RPM, not engine load.

That's a 10k ohm (10,000). 10 ohms would give you a problem. You can get them from any electronics supplier. Put it inline with the negative signal input. Don't know if that's a viable long term solution for you without knowing the rest of your system details, but what you've got now might not be viable either. These HU's are flaky, and I have no idea what your LOC is doing with the signal ground, what kind of load the HU is seeing, etc.

The issue doesn't have anything to do with the amp's quality, simply the architecture and how it integrates with the vehicle. Without researching that amp I wouldn't know, but I seriously doubt is has anything other than a traditional single-ended input.

 

If you're REALLY serious about changing amps, do as Keving suggested and get something with a balanced input. Arc and Jl would be RIGHT at the top of my list.

 

For now I think I'm going to leave it as it is since the whine is all but completely gone after moving the LOC.

But in case I ever do decide to change something out, what exactly is a balanced input? The only thing I know about inputs is an amp can have either speaker level or line level (RCA) inputs. Are speaker level inputs what are considered balanced inputs and RCA are unbalanced?

 

No, it's more complicated than that. It's hard to explain without getting too technical but it has to do with noise rejection.

 

No, speaker vs. line is a question of voltage level. Balanced vs. single-ended has to do with how the signal is carried. A single-ended signal carries a voltage on a single ++ conductor, and the -- is connected to the power ground. A balanced signal carries equal-but-opposite-polarity voltages on TWO conductors. A differential input is a type of balanced input that subtracts the -- from the ++ and uses the difference as the input signal. This rejects any noise that is common to both signal wires (called common mode rejection). Any noise that was coupled or received along the signal path would has the same voltage on both wires, and is removed by the differential input.

A balanced, differential input like the one on the amps we use will avoid (when properly installed) most common noise issues.

 

I know this wonderful thread is getting buried, but any updates?

I have started my install and am using the x9331 Molex jumper idea. The difference being as I am not sending signal back to the x9331 but rather running new speaker wire everywhere. The question on my mind is, should I run a bundle (8) of the unshielded speaker wire I tap off the x9331 down to underneath the passenger seat to my LC6i LOC, or should I find a place to put my LC6i closer to the x9331 in the drivers kick panel and just run shielded RCAs to my amp underneath my passenger seat?

-Z