White Noise In Water

[Ian2]

I just installed 6, 6.5" Kicker 45KM654Ls driven of a pp 900.4 amp. The two bow speakers are on the front two channels of the amp and the 4 midship/stern speakers are on the rear two channels of the amp. I tuned the amp on the trailer and it sounded great but when the boat is in the water I am getting static from the speakers on the port side, even with no other accessories running and the boat engine turned off. Does anyone know what could be causing this? Sub and tower speakers are both on separate amps.

Edited May 19, 2020 by Ian2

[hawaiianstyln]

how high are your gains and are both gains equally set?  do you have any components in between your deck and amps like an EQ or signal processor that would have internal gains set too high?

[David]

Assuming (dangerous, I know) when you state "...the boat engine turned off", the key is also completely 'OFF' (same as removed). Also assuming that the PPI input selector is positioned to drive all four channels with a single pair of RCA cables. If those issues hold true, then you might be fortunate to have a fairly easy diagnostic task of substitution and isolation. A) switch the L/R RCA at the source. B) Return that to the original position and switch the L/R RCA at the amplifier input. When and if the noise switches to the other side, you've isolated which component is the cause of the noise, whether source, cable or amplifier. Also, make sure that every RCA termination is well seated. If you discover the problem is within the amplifier, before repair or replacement, take a look inside to see if there's any surface corrosion on the input side with the pots & switches (deposits of a white powder-like residue). If so, use a spray can of DeoxIT D5 to clean up any residue.           

[Ian2]

@hawaiinstyln, I played with the gains alot and could not get the noise to go away. David, thanks for the advice I planned on switching the RCA's next time I am on the water, I actually went to do it while on the trailer and thats when I discovered the problem doesnt occur when on the trailer. 

[David]

21 hours ago, Ian2 said:

@hawaiinstyln, I played with the gains alot and could not get the noise to go away. David, thanks for the advice I planned on switching the RCA's next time I am on the water, I actually went to do it while on the trailer and thats when I discovered the problem doesnt occur when on the trailer. 

Anything is possible until proven otherwise. But until proven otherwise my thoughts are...unless there is a key engaged to activate some boat electronics component or a difference in the battery switch position, I know of no difference between 'on the trailer' and 'in the water' that would induce white noise. That's likely a coincidence only with the real cause being an undiscovered difference, like temperature or vibration or some other change in the condition. Plus the fact that the noise is in one channel only suggests the issue is independent of water or trailer.

Edited May 21, 2020 by David

[gary_tenison]

I would first suspect poor grounding. Check all your grounds and clean and tighten them. Consider using bigger gauge wire.

Also, since you have 4 speakers on your rear channel you are probably running the rear at 2 Ohms and the front at 4 Ohms. I think this will aggravate any gain issues you may have and your amp may not be rated for 2 Ohm loads...you can check that.

I suspect that your gains are not set correctly and you are clipping.  And clipping can sound like white noise or distortion also. I suggest you buy a Steve Meade DD1 distortion detector (its only like 100 bucks...not too bad) and start at the stereo signal outs, verify signal is clean up to a certain volume setting...check every 'RCA out' and note the lowest common volume setting which does not trigger the distortion light. Set your head unit at that number. Then do your digital signal processor outs also (if you have one) and then do your amp gains. Here is a description below from my post a "new stereo for my 2001 Sunsetter LXI"

-----------------------------------------------------------

SETTING Amplifier and HU GAINS CORRECTLY.

Once everything is wired up. Make sure the head unit is set flat...the base, treble, or eq is all flat or off. If you have a DSP inline, make sure your signal processor settings are all flat. No crossover settings, no EQ settings...completely flat. Make sure all amplifier gain and crossover settings are off or minimal...for instance, all gains are set to 0, all band passes are wide open,  such as your sub channel make sure its set for all pass or as high a setting as your amplifier allows. On my Alpine amp,  I think its 400HZ, so I set to 400 HZ. On the mid channels you would turn the high pass down as low as it goes, or 0/off if possible.

Pull the RCA lead off the left front channel of the signal processor input  if you are using one,  or off the amp if you are not. Plug the RCA from the head unit directly into the top of the SMD DD1 and turn it on.  Play the 1000 HZ - 0dB signal on the headunit (CD of tones comes with the DD1). Turn the headunit up to full volume,  On my Alpine HU, 35 is max, so I set to 35. Now look at the DD1...the 1000hz light should be lit, showing you have the signal, if your distortion light is also on, start decreasing HU volume until the distortion light goes off. Note what number you can use (if light went off at 32 then 32 is highest UNDISTORTED setting you could use. Now check right front, left rear and right rear...the lowest of the undistorted volume settings is then your highest volume you should use your headunit for (you might even want to go one click lower on HU to make sure there is no HU signal distortion. So you will set your headunit at that volume for the rest of these tests (although if you have a subwoofer signal RCA, you do the next step below...THEN your done with HU)

If you have HU base channel RCA, then also check your base channel. Use the 40hz - 0dB track. Unplug the sub channel RCA if you have one, and check HU volume setting again. Note the highest volume setting you can use before distortion light comes in, Ok...that tells you about your HU volume setting... 

There is another step here to set your DSP gains if you have one installed but I will leave that step out since you didn't seem to have a DSP.

Now you go on to the amp...with all the RCAs hooked up, and all gains set to zero, and the HU set at the highest undistorted volume which you just determined, disconnect the amp speaker wires. Use the cable that came with the DD1...plugged into the DD1 so you have a red lead and a black lead coming out of the top of the DD1...Play 1000HZ - (-5)dB signal from CD and put your leads on the left front speaker connectors on the amp...red on red and black on black. Now start turning up the gains for channels 1 and 2 until the 1000Hz light comes on and until the distortion light comes on. When the light comes on, slightly turn down gain until the light turns off again. Do that for all channel gains except for bass. Then set bass gains the same way but using 40Hz -(-10dB) signal. 

 If you put a stereo in your boat and never did this...It will make a HUGE difference. I GAURANTEE IT

 

[granddaddy55]

On 5/29/2020 at 6:38 PM, gary_tenison said:

I would first suspect poor grounding. Check all your grounds and clean and tighten them. Consider using bigger gauge wire.

Also, since you have 4 speakers on your rear channel you are probably running the rear at 2 Ohms and the front at 4 Ohms. I think this will aggravate any gain issues you may have and your amp may not be rated for 2 Ohm loads...you can check that.

I suspect that your gains are not set correctly and you are clipping.  And clipping can sound like white noise or distortion also. I suggest you buy a Steve Meade DD1 distortion detector (its only like 100 bucks...not too bad) and start at the stereo signal outs, verify signal is clean up to a certain volume setting...check every 'RCA out' and note the lowest common volume setting which does not trigger the distortion light. Set your head unit at that number. Then do your digital signal processor outs also (if you have one) and then do your amp gains. Here is a description below from my post a "new stereo for my 2001 Sunsetter LXI"

-----------------------------------------------------------

SETTING Amplifier and HU GAINS CORRECTLY.

Once everything is wired up. Make sure the head unit is set flat...the base, treble, or eq is all flat or off. If you have a DSP inline, make sure your signal processor settings are all flat. No crossover settings, no EQ settings...completely flat. Make sure all amplifier gain and crossover settings are off or minimal...for instance, all gains are set to 0, all band passes are wide open,  such as your sub channel make sure its set for all pass or as high a setting as your amplifier allows. On my Alpine amp,  I think its 400HZ, so I set to 400 HZ. On the mid channels you would turn the high pass down as low as it goes, or 0/off if possible.

Pull the RCA lead off the left front channel of the signal processor input  if you are using one,  or off the amp if you are not. Plug the RCA from the head unit directly into the top of the SMD DD1 and turn it on.  Play the 1000 HZ - 0dB signal on the headunit (CD of tones comes with the DD1). Turn the headunit up to full volume,  On my Alpine HU, 35 is max, so I set to 35. Now look at the DD1...the 1000hz light should be lit, showing you have the signal, if your distortion light is also on, start decreasing HU volume until the distortion light goes off. Note what number you can use (if light went off at 32 then 32 is highest UNDISTORTED setting you could use. Now check right front, left rear and right rear...the lowest of the undistorted volume settings is then your highest volume you should use your headunit for (you might even want to go one click lower on HU to make sure there is no HU signal distortion. So you will set your headunit at that volume for the rest of these tests (although if you have a subwoofer signal RCA, you do the next step below...THEN your done with HU)

If you have HU base channel RCA, then also check your base channel. Use the 40hz - 0dB track. Unplug the sub channel RCA if you have one, and check HU volume setting again. Note the highest volume setting you can use before distortion light comes in, Ok...that tells you about your HU volume setting... 

There is another step here to set your DSP gains if you have one installed but I will leave that step out since you didn't seem to have a DSP.

Now you go on to the amp...with all the RCAs hooked up, and all gains set to zero, and the HU set at the highest undistorted volume which you just determined, disconnect the amp speaker wires. Use the cable that came with the DD1...plugged into the DD1 so you have a red lead and a black lead coming out of the top of the DD1...Play 1000HZ - (-5)dB signal from CD and put your leads on the left front speaker connectors on the amp...red on red and black on black. Now start turning up the gains for channels 1 and 2 until the 1000Hz light comes on and until the distortion light comes on. When the light comes on, slightly turn down gain until the light turns off again. Do that for all channel gains except for bass. Then set bass gains the same way but using 40Hz -(-10dB) signal. 

 If you put a stereo in your boat and never did this...It will make a HUGE difference. I GAURANTEE IT

 

that box works great, especially if you have the older HU’s  with CD built in

friend was eager to use it on my noisy system after we put everything on remote power and ground  because he wanted to have opp ti use it again after paying for it to do his

Edited June 22, 2020 by granddaddy55