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static/sound in speakers


90oldskool

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my boat had 1 amp/sub and the 4 6.5 speakers were powered from the head unit . I added a 4 ch to power in 6.5 and now there is static in the speakers (static is present with HU on or off), and with the head unit off but the phone plugged into the AUX music can be heard very low . The RCA's are ran the opposite directions as power/ground. I have the rca come off the headunit to the 1 ch sub amp then from bypass port from amp one to the 4 ch amp rear input. I tried running rca from head unit to 4 ch then by pass to 1 ch amp- sub made no sound this way(assumption is because I have the 4 ch set on HP).

 

I lowered the gain and the static got less but is still present . 4 ch is a Rockford prime and 1 ch is a Rockford punch. Any suggestion on how to get the static gone/best way to wire off headunit to which amp first? Also sub is not nearly as loud as before addition 2nd amp.

 

I already changed out the cheapo RCA cable that came with the wiring kit to a set of twisted pair of Rockford fosgate cables but this did not make much difference .

 

Currently the 4 6.5 are wired to only 2 ch's of the 4 ch. they are 50 rm speakers with the amp being 600 watts- 150rms x4

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static is present with HU on or off),  and with the head unit off but the phone plugged into the AUX music can be heard very low

How is the amp on with the head-unit off? Was this done just for testing? Its also odd that you hear music with the head-unit off. Have you connected your MP3/Ipod/Phone directly to the amp inputs with a 3.5mm x RCA cable? 

 

59 minutes ago, 90oldskool said:

I tried running rca from head unit to 4 ch then by pass to 1 ch amp- sub made no sound this way(assumption is because I have the 4 ch set on HP)

But was was the outcome of the static with the RCAs run direct from head-unit to in-boat amp? 

 

1 hour ago, 90oldskool said:

currently the 4 6.5 are wired to only 2 ch's of the 4 ch. they are 50 rm speakers with the amp being 600 watts- 150rms x4

Have you tried wiring each speaker to its own chnls? Id do this anyway. 

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5 hours ago, 90oldskool said:

my boat had 1 amp/sub and the 4 6.5 speakers were powered from the head unit . I added a 4 ch to power in 6.5 and now there is static in the speakers (static is present with HU on or off), and with the head unit off but the phone plugged into the AUX music can be heard very low . The RCA's are ran the opposite directions as power/ground. I have the rca come off the headunit to the 1 ch sub amp then from bypass port from amp one to the 4 ch amp rear input. I tried running rca from head unit to 4 ch then by pass to 1 ch amp- sub made no sound this way(assumption is because I have the 4 ch set on HP).

 

I lowered the gain and the static got less but is still present . 4 ch is a Rockford prime and 1 ch is a Rockford punch. Any suggestion on how to get the static gone/best way to wire off headunit to which amp first? Also sub is not nearly as loud as before addition 2nd amp.

 

I already changed out the cheapo RCA cable that came with the wiring kit to a set of twisted pair of Rockford fosgate cables but this did not make much difference .

 

Currently the 4 6.5 are wired to only 2 ch's of the 4 ch. they are 50 rm speakers with the amp being 600 watts- 150rms x4

Ok, sounds like the amplifier is still on when the head unit is off if it is playing lightly through the speakers with the MP3 jack. I have seen this happen before in other systems if your amplifier is still on. You sure your wiring is solid and connected properly? It should shut down when the head unit does. 

What head unit and amplifiers are they? This will help as some amplifiers have better internals than others and it may be amplifying a smaller issue. Does the head unit have more than one pre out? I like utilizing these better than using a bypass on a amplifier, unless it's balanced and un filtered. 

basically if you have a shielding (ground) issue in the head unit or combined with low grade inputs on a amplifier, still powered on with head unit off. You will hear the raised noise floor or hiss for sure. 

 

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when I bought the boat , the head unit was wired to a switch , since owning I added a perko switch and 2nd battery for system only. amps are wired to 2 side of perko directly, allowing me to turn the switch to head unit off with the amps remaining on. sorry I left that part out of the first post.

23 hours ago, MLA said:

But was was the outcome of the static with the RCAs run direct from head-unit to in-boat amp? 

 

it was less but still present.

 

23 hours ago, MLA said:

Have you tried wiring each speaker to its own chnls? Id do this anyway. 

I wired to only to 2 ch because there is only one set of rca's coming off the head unit right now , there is rear and front RCA's on the head unit and I will try wiring it this way tomorrow but  that still leaves the question on how to get the LP signal to sub amp . I could Y split off on set of rca for 4 ch and then run one set of rca to sub amp  I guess. I wired to only 2 ch because I will be ordering tower speaker soon and was going to use remaining ch for each tower speaker. Plan was to use rear RCA for inboard/sub and front RCA for towers. Be able to use fade to adjust the bal. this way....

 

18 hours ago, Truekaotik said:

What head unit and amplifiers are they? This will help as some amplifiers have better internals than others and it may be amplifying a smaller issue. Does the head unit have more than one pre out? I like utilizing these better than using a bypass on a amplifier, unless it's balanced and un filtered.

head unit is a cheap BOSS (came with boat) 400x1 is a Rockford punch , 600x4 is a Rockford prime . both class D

 

Oh and out on the water today (testing was done in driveway till now ) there is LOTS of motor whine in speakers , mainly when starter was engaged .

23 hours ago, MLA said:

How is the amp on with the head-unit off? Was this done just for testing? Its also odd that you hear music with the head-unit off. Have you connected your MP3/Ipod/Phone directly to the amp inputs with a 3.5mm x RCA cable? 

I have no idea how it is bleeding through . I had pandora on my phone connected to the AUX on HU through the 3.5 mm jack on headunit . Tried Pandora to try to eliminate any radio static .

Edited by 90oldskool
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You should really reach out to your local marine stereo shop. You have a couple of issues that need addressed by your posts that a professional can fix. 

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2 hours ago, Truekaotik said:

You should really reach out to your local marine stereo shop. You have a couple of issues that need addressed by your posts that a professional can fix. 

I spoke with the local shop that did the sub/1ch amp install, their suggestion was to do a 4 ch rca line output convertor . the link is not the exact one that was in their show but same concept.

http://www.bestbuy.com/site/axxess-4-channel-line-output-converter/9616393.p?id=1219424287450&skuId=9616393

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1st thing I would do is address the obvious switch/battery/audio gear wiring. As it is now, I think youve got audio gear drawing off both banks, with almost always invites noise. You need someone that understands marine audio and how to properly set up a dual bank battery system. You need the head-unit and amp's B+ on the right post on the switch, you need to the helm stereo rocker triggering the right circuit on the head-unit and you need to the head-unit to turn the amps on. 

For the lack of a 2nd pair of RCA outputs, and after the noise is isolated and cured, I would run the RCAs into the 4 chnl, then use the 4 chnl's pass-thru to the sub amp. Better solution would be to put in a 2 chnl line driver or something like the Kicker ZXM-RLC. 

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Rather than having a stereo shop add a couple of products to an existing system, you needed to have them do a comprehensive installation, even if that meant re-doing much of what was already there.

Good advice from the pros above. I agree with them that you most likely have some installation issues the way the system is presently set up. And a Boss HU is always a concern. It's an older boat, and when you mix shock/vibration with a wet/humid environment, even 5 years can be a long time. So there can be lots of connections and terminations that must be inspected and proven.  

You have to begin with a few absolute "knowns". Start moving this diagnosis towards black and white terms. I would begin by unplugging the inputs of both amplifiers, turning these amplifiers on, with the gain at 60 to 65% and see if you have noise. The ideal method would be to short the inputs but you don't need to if there is no noise. Next, plug the RCAs back into the amplifiers with the RCAs disconnected at the other HU end. In this case the RCAs should be shorted to get a valid test. If you still have no noise then this narrows down the cause to either 1) the HU, or 2) HU to amplifier(s) relationship. If its a relationship issue then it is cured via re-wiring the system. If its a HU issue there are numerous solutions. But now you are moving in a specific direction with a narrowed focus and towards a solution.   

Btw, since the subwoofer amplifier is in the lowpass mode, it will filter out the noise that you have in the other amplifier.  

Edited by David
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Connected another RCA to head unit , so rear RCA is going to sub amp and front is going to 4ch amp (only using 2 ch right now) . Then rerouted rca's farther away from power/gound wires . on 4ch amp lowered punch eq to about 40% and gain to about 4 on the 1-11 scale. 90% of static is gone . ran motor on water hose , no input at start up any more. The amps power on and off with the HU switch , Found the audio shop just spliced the remote wire into the power wire off the toggle switch . So if I hit the power button on head unit the amps will not turn off but then when I hit the toggle switch everything powers off.

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On 5/1/2016 at 10:37 AM, David said:

You have to begin with a few absolute "knowns". Start moving this diagnosis towards black and white terms. I would begin by unplugging the inputs of both amplifiers, turning these amplifiers on, with the gain at 60 to 65% and see if you have noise. The ideal method would be to short the inputs but you don't need to if there is no noise. Next, plug the RCAs back into the amplifiers with the RCAs disconnected at the other HU end. In this case the RCAs should be shorted to get a valid test. If you still have no noise then this narrows down the cause to either 1) the HU, or 2) HU to amplifier(s) relationship. If its a relationship issue then it is cured via re-wiring the system. If its a HU issue there are numerous solutions. But now you are moving in a specific direction with a narrowed focus and towards a solution.   

Btw, since the subwoofer amplifier is in the low

When i pull the RCA out of the amp , the static leaves, i have not pulled the headunit to try remove the RCA for that test.  The headunit ground was on the starter battery and the power wire to the toggle was on the starter battery as well. Moved these over to battery 2 . When I use pandora , there is very little static now , only can be heard with the volume level below 3. There is more static when using radio but that could just be from a weak single . I will try to remove the RCA's from rear of head unit this weekend , new tower speakers will be delivered Friday, so i'll have some work cut out for myself. 

 

So if the static leaves with the RCA's removed from the head unit but connected at amp  , and also leaves with the RCA's removed from amps but connected to headunit, that means the Headunit is producing the static correct? 

one last question : the audio shop that installed the first amp, also installed the perko and 2nd battery. They just ran a 0 ground wire from battery 1 to battery 2 . Is this the correct way to do this  or is there a better way i should try ? 

Edited by 90oldskool
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  • 3 weeks later...

At a lost here. So when i remove the rca's from the amp , low static is still present . When gain , freq and punch is lowered all the way -sound still present . 

Headunit ground was connect to starter battery - , this has been moved now . Remote wire from amp has been moved to the remote on HU now so everything powers on and off together . (audio shop ran to toggle power ) Took power wire from perko and ran direct to stereo battery for a test - sound was worse . 

The high pitch sound is gone now with the punch turned down all the way . 

I have the inboat amp ch set on HP and the tower set up AP .  

 

What is left to check????

the only thing I'm unsure of is , that battery 2 - is ran to battery 1-. Is there a better way to do this .  ill change out the HU if need be , but since the sound is present with the RCA's disconnected , doesn't that rule out the HU being the cause?

Moved ground wire from sub amp to 4 ch to test. one ground wire is a JL and the other was a amazon special- did not have any effect . 

Before 4 ch amp was installed, with the same speakers ran off HU power , there was no disturbance present . 

@David @MLA - Do you have any input ??

Edited by 90oldskool
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Here are a few suggestions. Start doing business with a local dealer who can service your problems rather than bringing in gear from a variety of sources who cannot help or support you. Stop adding additional components until you solve your existing issues.

Noise: You can't run the amplifier gain all the way down in consideration of the fact that you have minimal preamp voltage. You have to begin at the very end of the signal path and determine at which point you do and do not have noise. At that point of the first introduction of noise, you have to determine the cause/source of the noise. Is it on the DC line, is it coming from the source, is it radiated/induced as a matter of proximity, etc.? Then work in reverse one element at a time. The amplifier should have zero noise when powered up with the gain at 50% with no input (other than the slightest amount of hiss with your ear to the tweeter). However, you may have to short/close the amplifier input for this to be a completely precise test. If you have noise at the amplifier with no input, then go no farther. Focus on the amplifier and only those elements directly associated with the amplifier. Proximity to the source of noise. Internal generated noise. Poor ground. Shorted or mis-wired speaker wire. Note, on most amplifier topologies the speaker ground is 'above the supply ground' and connected to the input ground. So if you allow noise access to the output, you introduce noise into the input. Another point, amplifiers have a DC to AC to DC high speed switching power supply. It's the ultimate filter. So if there is an AC or noise component at the voltage supply, this makes it nearly impossible to pass through the power supply...provided you have a good ground, good voltage, wired correctly, and a non-defective product. The type of noise will give you a strong indication as to the noise source. Only with the boat running? Without the boat running but with the key on? Totally isolated from the boat with an isolated test battery?    

 

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