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Old 07-20-2017, 04:50 PM
Brantf Brantf is offline
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Speaker noice

I installed a pair of rev 10 wetsound speakers with a wetsounds amp. When the boat is not running they sound great, when the boat is running you can hear a humming noise. Doing a little research I thought it was maybe a ground loop so I tried grounding the stereo head to the amp, that didn't work. Next I tried unplugging the rca's to the amp and the hum went away. Plugged my phone directly into the amp and the speakers sound great with know hum. Any ideas on what the cause could be??
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Old 07-20-2017, 05:18 PM
MLA MLA is online now
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I thought it was maybe a ground loop so I tried grounding the stereo head to the amp,
Very possible, so keep researching because audio ground loop goes way beyond the DC ground circuit. I would certainly consult with your Wet Sounds dealer. They should be your first line of defense so to speak, when problems pop up. They can help with setup and tuning, which can often prevent noise in the first place.
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Old 07-20-2017, 05:25 PM
waterlogged882 waterlogged882 is offline
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Originally Posted by Brantf View Post
I installed a pair of rev 10 wetsound speakers with a wetsounds amp. When the boat is not running they sound great, when the boat is running you can hear a humming noise. Doing a little research I thought it was maybe a ground loop so I tried grounding the stereo head to the amp, that didn't work. Next I tried unplugging the rca's to the amp and the hum went away. Plugged my phone directly into the amp and the speakers sound great with know hum. Any ideas on what the cause could be??
How much are you selling your speakers for? I am interested. Thanks
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Old 07-20-2017, 06:57 PM
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JimN JimN is offline
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Originally Posted by MLA View Post
Very possible, so keep researching because audio ground loop goes way beyond the DC ground circuit. I would certainly consult with your Wet Sounds dealer. They should be your first line of defense so to speak, when problems pop up. They can help with setup and tuning, which can often prevent noise in the first place.
It doesn't go "way beyond the DC ground circuit", it's caused by the DC circuit trying to make up a difference in voltage between the head unit and the amplifier(s) and any other pieces using the battery for power. Since it can make up this difference by using the audio cables, it causes the noise because the power supply and audio circuit have become one. This is the reason ground loop isolators usually consist of a small transformer- it completely breaks the connections on the + and -, using the principle of magnetic coupling and inductance.
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Old 07-20-2017, 06:58 PM
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JimN JimN is offline
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Originally Posted by Brantf View Post
I installed a pair of rev 10 wetsound speakers with a wetsounds amp. When the boat is not running they sound great, when the boat is running you can hear a humming noise. Doing a little research I thought it was maybe a ground loop so I tried grounding the stereo head to the amp, that didn't work. Next I tried unplugging the rca's to the amp and the hum went away. Plugged my phone directly into the amp and the speakers sound great with know hum. Any ideas on what the cause could be??
Do a search for the other threads where the solution has been posted. It works.
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Old 07-20-2017, 07:39 PM
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Originally Posted by JimN View Post
It doesn't go "way beyond the DC ground circuit", it's caused by the DC circuit trying to make up a difference in voltage between the head unit and the amplifier(s) and any other pieces using the battery for power. Since it can make up this difference by using the audio cables, it causes the noise because the power supply and audio circuit have become one. This is the reason ground loop isolators usually consist of a small transformer- it completely breaks the connections on the + and -, using the principle of magnetic coupling and inductance.
Jim,

You and I both know and understand what ground loop is and how a GLI works. Are you telling the OP to ignore the other half of the DC circuit and fixate on the component B-? I ask because once you start talking about where a GLI goes in the system and what it does, we are not longer talking about the DC ground circuit, but rather a voltage differential on the ground side of the audio signal path.

Further, you describe ground loop as "caused by the DC circuit trying to make up a difference in voltage between the head unit and the amplifier(s) and any other pieces using the battery for power". Its been a long time since I took basic mobile DC, but doesnt it consist of a positive and negative circuits, in order to be a complete circuit? Isnt it possible that this making up of a difference can be related to the component B+ side and not isolated to only the B-?
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Old 07-20-2017, 08:13 PM
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JimN JimN is offline
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Originally Posted by MLA View Post
Jim,

You and I both know and understand what ground loop is and how a GLI works. Are you telling the OP to ignore the other half of the DC circuit and fixate on the component B-? I ask because once you start talking about where a GLI goes in the system and what it does, we are not longer talking about the DC ground circuit, but rather a voltage differential on the ground side of the audio signal path.

Further, you describe ground loop as "caused by the DC circuit trying to make up a difference in voltage between the head unit and the amplifier(s) and any other pieces using the battery for power". Its been a long time since I took basic mobile DC, but doesnt it consist of a positive and negative circuits, in order to be a complete circuit? Isnt it possible that this making up of a difference can be related to the component B+ side and not isolated to only the B-?
Since a power supply tries to balance itself, and the laws governing voltage & current tell us that they will, I don't think we need to go into the whole design but I don't think anyone has seen a ground loop that was caused by shortcomings in the audio chain. If you connect 12V+ to a head unit and nothing else, you'll measure +12VDC on every wire and the chassis if you connect the other meter lead to the metal vehicle chassis or - battery terminal. I found out about this when I started doing car audio and it made sense after someone explained it to me. I also got to feel the effect of lifting the power supply ground while I sat on the sill of a Corvette in humid weather when I was touching the un-grounded head unit with my bare leg (it was Summer- I was wearing shorts)- I did not like that.

The difference in voltage available to each unit causes the imbalance- since the audio circuits are ultimately connected, they are available for the DC to travel between them in the search for the path of least resistance. If someone wants to determine the resistance needed to balance these differences, I think it would remove the noise, as well. The problem with that is the required resistance would change as components become warmer and their conductivity changes. Better to just supply equal voltage to each and equal ground path resistance.

This is the reason for using distribution blocks for the positive and negative power cables, then taking the power for each device from each block, as needed. As long as the wire gauge is sufficient, there should be no difference in voltage provided and therefore, no noise. This assumes that the dash wiring has been abandoned and only used to latch the relay on the red wire.
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Old 07-21-2017, 06:51 AM
alexsims1256 alexsims1256 is offline
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Originally Posted by Brantf View Post
I installed a pair of rev 10 wetsound speakers with a wetsounds amp. When the boat is not running they sound great, when the boat is running you can hear a humming noise. Doing a little research I thought it was maybe a ground loop so I tried grounding the stereo head to the amp, that didn't work. Next I tried unplugging the rca's to the amp and the hum went away. Plugged my phone directly into the amp and the speakers sound great with know hum. Any ideas on what the cause could be??
Where is your head unit grounded at? Might want to try to move the ground to your amps ground if its not there already. What also would help is if the stereo is isolated from the ignition power on a seperate circuit breaker, this also makes it where you will not have to have the ignition switch on to listen to the stereo and you will not have to worry about engine noise coming through the system.
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Old 07-21-2017, 09:07 AM
Brantf Brantf is offline
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Jim, I am very much an amateur at this but am trying to learn everything. I spent a lot of time going through other threads and still haven't pin pointed my exact issue(maybe I missed the right thread). It's difficult to troubleshoot and test since I have to be in the water engines running to hear the noice. Based in what you've said I have to assume I went wrong somewhere along the way wiring all the power in. A previous thread I read is why I pulled the Hu stock ground and moved it to the largest amp to ground. Prior to that I always had a very loud noise when I would turn my blower on. Moving the Hu ground fixed that but not the lower noise while the engine is running. From what you said I think I may try distribution blocks next, do you think that would be a good next step?

Currently the way I have everything wired.
I have an XS battery to supplement the main battery. The one I use is designed to supply the power when the engine is not running. The XS battery is connected directly to the +\- terminals on the primary battery. The power supply to my Amps(I have one for my tower speakers and one for my internal component speakers) is connected directly to the positive on the XS battery. Grounds are connected to the negative terminal on the primary battery. My small amp is under the console, large amp is toward the back of the boat so I didn't have to run power as far. The rcas for both Amps come out of the HU and go to individual volume controls so I could control them separately. From the volume controls a second set of rcas then run to the Amps. Also, for about 5 feet the rcas for my tower speakers run fairly close to the power supply to my smaller amp, could that be a possible cause too?

I have to assume that they way I have my power and grounds hooked up is the cause. The way I have my power hooked up is how the manufacturer of the battery specified so the amp would pull power the the XS when the boat is not running. Any thoughts? Sorry if some of what I said didn't make much sense, again I am very much an ammauture at this and have learned everything from doing.
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Old 07-21-2017, 09:10 AM
Brantf Brantf is offline
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A few pictures I had of it helps make sense of anything
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