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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??

  • #2
    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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    • #3
      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
      93 190
      (safe click)
      John 14:6
      (safe click)

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      • #4
        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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        • #5
          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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          • #6
            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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            • #7
              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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              • #8
                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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                • #9
                  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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                  • #10
                    A few pictures I had of it helps make sense of anything
                    Attached Files

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                    • #11
                      Originally posted by Brantf View Post
                      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.
                      Power and grounding are tricky- it's not possible to see that a problem exists in all cases and connections may look perfectly clean when problems show up.

                      It's a PITA, but the first step in removing noise problems is starting at the battery- clean and tighten the battery connections, replacing any terminals or cables that are damaged/corroded and cleaning all points of contact. I have seen noise problems stop when battery posts and cable ends were cleaned.

                      SIB-KIS, 'See It Big-Keep It Simple. Make sure the audio system is separate from the rest of the gauges and other electrical system unless you're connecting some of the Fusion, Rockford-Fosgate and other brands that work with NMEA-2000 to interface with the GPS unit. Make sure the power cables are adequate and that the alternator and its charging lead are up to the task of operating everything on the boat- when an alternator is over-taxed, part of it will not perform as needed and noise is one of the results, failure is another. Alternators get hot when used normally, they get REALLY hot when the accessories are treating it like a farm animal. Bearings, connections, regulator/rectifier and brushes fail, leaving you with a dead battery, or worse.

                      Too many ground paths can be the whole reason noise enters the system and this is part of the reason the one power + and power- method works. Avoid running any audio or audio system power cables parallel and close to other power wires- as shown in the noisy tweeter thread, digital dash gauges make noise that can be picked up by the audio system in places that aren't normally points of entry and in that case, it was due to the installation of the speaker crossover. Since your noise disappears when the audio cables are disconnected, this isn't the same problem.

                      Placing one amp in a location because it's more convenient is an easy way to have this problem. Do you have a multi-meter? If not, I would suggest buying one (doesn't need to be expensive) and becoming familiar with it. It's good to have a bit of background in electricity to know what voltage, current and resistance are and how they interact. It's not necessary to know everything, but the basics are good to know.

                      This link has lots of good info about 12V systems and it includes wire gauge charts for power and speakers.

                      http://www.the12volt.com/

                      If you do have a multi-meter, measure the voltage at the power terminals at the amplifiers- I would bet you'll see different numbers at each. If you have a spare piece of wire (doesn't need to be huge), connect it from the ground of one amp to the ground of the other amp- if the noise stops, find a way to make it a permanent connection or move the second amp to the same location as the original.

                      Another solution I have used is grounding the RCA cable shield- connect a wire to the outer sleeve of the plug or jack to a good ground- if the noise stops, solder the wire onto the cable and ground it.

                      You can also measure voltage between the amplifier ground connections- if it's a small number, you could use a ground loop isolator. I use PAC but have also used the ones from Radio Shack- if you're near one of the remaining RS stores, they might have some of these. If it causes the sound quality to change, I would recommend checking the rest of this and making the electrical connections as good as possible.

                      Battery condition can have an impact on noise, too- the battery is a large noise filter and if it has been depleted more than a couple of times, it can't do its job as well as it should. It may still start the engine, but it will be less than great for other functions.

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                      • #12
                        Thank you for all the tips! Can't tell you how much it's appreciated. When I have a chance I will give everything you suggested a try to see if I can't get to the bottom of this. I do have a multi meter so I can test voltage after I spend some time studying the website you provided. When you say ground the rca cable shield. Do I need to cut the outside covering off to get to the shield on the rca cable or how so you recommend do that?

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                        • #13
                          Where is the appropriate spot to set this multimeter to test?
                          Attached Files

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                          • #14
                            Originally posted by Brantf View Post
                            Thank you for all the tips! Can't tell you how much it's appreciated. When I have a chance I will give everything you suggested a try to see if I can't get to the bottom of this. I do have a multi meter so I can test voltage after I spend some time studying the website you provided. When you say ground the rca cable shield. Do I need to cut the outside covering off to get to the shield on the rca cable or how so you recommend do that?
                            If the shield on the plug is visible, you should be able to solder onto ityou can try grounding it at both ends- it doesn't matter as long as it works, but if it fails to help, you'll need to do the other wiring method.

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                            • #15
                              Originally posted by JimN View Post
                              If the shield on the plug is visible, you should be able to solder onto ityou can try grounding it at both ends- it doesn't matter as long as it works, but if it fails to help, you'll need to do the other wiring method.
                              Jim, in an effort to get this all right this time around while I'm messing with it. Do you think I would benefit from moving my second amp under the console where the first is. Then running a single two gauge power and ground to distribution blocks under the console. Finally powering both Amps and the Hu from those single distribution blocks? Or should I be putting the distribution blocks close to the battery? I know you are suppose to put the fuses near the battery on each power run so I wasn't sure how that would work.. could I fuse the 2 gauge to the distribution block?

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