White Noise from Tower Speakers

[David Analog]

You have established the following per your posts.
You have noise anytime you use the HU speaker outputs to amplifier inputs.
You have noise with any amplifier when running from the HU speaker outputs but not with any amplifier when running from the HU preouts.
You have noise with or without a line level convertor.
Based on that, I'm coming to the conclusion that no matter what you do, if the noise persists, even after adjusting gain levels, then you have to run 100% preouts. The HU speaker level output section may not like any termination other than push/pull through a typical speaker impedance.
Chasing grounds and other issues isn't making much sense, since you have scenarios with the same equipment that is noise free.
A line driver/controller may be inevitable.

[MLA]

Yes I do have dual batteries and the power and ground for both amps are hooked up to the distribution block that came from the factory in the passenger side storage. I haven’t looked but the batteries are only a couple feet away so I am guessing the + comes off of the battery switch and the – goes back to one of the batteries? I will take a closer look at exactly how they are wired. Not sure exactly how the hu gets power since it is on the other side of the boat.

I will re-arrange the hi low adapter to where it is closer to the amp instead of the hu. Is there a defined process for how to adjust these things? The one I got didn’t come with any instructions (Kicker KISLOC). Just turn the screws and see if it makes a difference? I think I actually have a gli at home so I might just try it to see what it does but still work on solving the root of the problem.

Honestly I know deep down that a line driver is the way to go for the best audio quality but I am trying to fight it. I had one on my last boat and it worked well with no complaints but I actually really like the simplicity of how the fusion unit does zone control and the bigger issue is that I don’t want to lose the ability to control volume/zones from my transom remote.

To do list for me: 
1. Re-locate hi lo adapter to near amp
2. Play with adjustments on hi lo adapter
3. Turn gains way down on amp and see if noise goes away
4. Take a picture and/or record my amp settings
5. Figure out exactly how everything is getting power

1) im not sure thats as important with the KISLOC as it is with other simple hi to low adapters. Even then, you will still need a very short RCA with males on both ends.
2 & 3) I would set these to their lowest points now in order to eliminate the noise and worry about output later
4) really need to know this and how the RCAs are connected to the amp
5) although i dont think this is a typical ground loop issue, i still like to cover the basics and make sure all the gear sees the same battery voltage. Working on a 2015 MC with noise issues and the amp is wired to the cranking battery and the one amp is wired to the house battery from the factory and there is noise when the engine is running. So, even the best with the best gear can have some issues from the factory.

[philwsailz]

All arrows point to a need to use a dual zone splitter. Or better yet a line driver like the ZXM-RLC

I'm with David and Mike. Using the high-level out does not appear to be a workable solution.

Phil
Kicker

[cpropes2005]

Well it started raining before I could get all of the testing done but I took out the hi lo converter to move it closer to the amp and before I reinstalled it I decided to play with the gains using the original setup of hi level inputs on the amp. I found that with gains at half way the noise was still there but if I turned them all of the way down it went away so maybe this is just a case of me not taking the time to properly tune the system yet? I didn't get a chance to slowly turn the gains back up to see exactly where the noise comes back but honestly the speakers where still plenty loud for my use with them all of the way down so I will probably just leave them that way until I get the time/space/knowledge to properly tune it. To answer the question about the RCA setup the high level signal is ran from the hu to near the amp with speaker wire and then I have the kicker KISL converter that change the connection to RCA.

Thanks for all of the helpful advice and apologies for my ignorance on some of this stuff!

[philwsailz]

Are you using a KISL?????? Or a KISLOC????

Big difference. If a KISL your tower amp gains will end up being turned down almost all the way.

Phil
Kicker

[cpropes2005]

Initial setup and where I am back to now is a KISL and the amp set to high level inputs. I think the problem like you mentioned was mainly just that I had the gains set too high for use with the KISL. I do also have a KISLOC which I was experimenting with because I was thinking that maybe it would be better to convert to low level before entering the amp but as long as the noise is gone and I can still get decent volume with the gains all of the way down I will probably just stick with the KISL set up until I decide if I want to bite the bullet and install a line driver.

[philwsailz]

Consider this:
A cheap radio may only put out 1 or 2 volts of signal on the RCA pre-outs
A good head unit might put out 5 volts, but really they often only put out 2 or so.
A good line driver will bump voltage up, sometimes as high as 10 volts, (without adding any significant noise)
A pair of speaker wires each will often have the SAME voltage as a line driver, the difference being that the speaker outputs have the current required to drive a pair of speakers. The line driver, while operating at the same amplitude, lacks the current required to drive a speaker.

When we set the gains on any amplifier, we do so knowing the gain controls are not volume controls. Regardless gain setting, the amp will only deliver so much power; setting gains higher will not make the amp play louder. It only makes the amp get louder more quickly, as it responds to the input voltage.

The gain control works in the front end of the amp, and adjusts the amp's sensitivity. A high qain setting means high sensitivity; it "looks' for lower voltage signals to amplify... like the weak signal coming from the radio, AND all the noise that ends up on literally every piece of wire out there... The lower the radio's output voltage, the closer in amplitude it is to every other noise in the system. The amp makes all that stuff louder; radio signal AND noise.... When you have a higher signal voltage, your music signal is delivered to the amp at a much greater amplitude than the system noise. With more and more signal voltage, you can reduce the amp's sensitivity, and it will amplify less and less of the noise inherent in the system.

So...

With a low input voltage, (think lower quality head unit with 1-2V outputs) radio, you might have to set the amp gains at 12-o'clock, (as seen on a clock) or higher to get the amp to deliver max power when the radio is similarly turned up close to max.

With a higher-voltage radio you might only have to set the amp gains at 9 or 10-o'clock to get the same output

With a line driver or using speaker wires, the amplifier can be set with its gains even lower...

* The HIGHER the voltage, the greater difference in amplitude between the desired audio signal and the inherent system noise
* The HIGHER the voltage you can send to the amp, the lower you can set your gains.

This will be lost on people, but gains all the way down does not mean OFF. It only means the amp needs no increase in sensitivity to drive the amp to full power. This can be done with a good solid high-voltage signal; something you CAN get many times with a speaker-level input.

Bottom line: As the OP confirmed, the gains were simply set too high for use with a speaker level input.

FYI

Phil
Kicker

[cpropes2005]

Great info all around on this thread. Thanks guys for taking the time to help educate me and whoever else might read this.