Before I am dropping $2500 on Stereo hardware...

[Hezi]

In your boat the ground wire on the head unit harness should be black, labeled gnd, in pin 8 of the harness with only two or three wires from the headunit to the boat harness. Since it is ground it should not be switched. If you added a ground disconnect I recommend that you never turn it off. Everything should function just as it did before except that you will have a much better and similar path to ground.

You are right. Only the positive is switched. Why didn't I asked this here before??? I will try this next time I'm working on the boat which should be this Friday. I just ordered another pair of MX 650 in a kicker enclosure to add to the tower. This is going to face forward and give me the loudness I need when the boat is beached and we are hanging on the sand bar. I took the boat to a JL installer to go over my install and figure out the noise. After 3 hours, all he did was to lower the gain to mitigate the noise. He couldn't find any other issue and blame it on the SW420BT EQ.
Thanks a bunch!

 

[Mainah]

You are right. Only the positive is switched. Why didn't I asked this here before??? I will try this next time I'm working on the boat which should be this Friday. I just ordered another pair of MX 650 in a kicker enclosure to add to the tower. This is going to face forward and give me the loudness I need when the boat is beached and we are hanging on the sand bar. I took the boat to a JL installer to go over my install and figure out the noise. After 3 hours, all he did was to lower the gain to mitigate the noise. He couldn't find any other issue and blame it on the SW420BT EQ.
Thanks a bunch!

I have never understood why folks use ground loop isolators in car/boat autio systems or can’t track down the source of noise. Keeping the amps, headunit, and eq all on the same path to groung will prevent ground loops. A large path to ground with also double as a shunt giving an easy path to ground for high frequency noise to dissipate.

If that does not work an oscilloscope can identify the component producing the noise. It is pooible but rare that a component is bad an that can be the cause. Some components are just “dirty” with power switching power supplies.

I would retune your amps after doing this and installing the additional speakers.

 

[CraigLombardi]

I just installed the wetsounds stealth 10 on my tower and I'm amazed by how good it sounds. You can direct it backwards, forward facing or down

Do you have a pic and did you use the stock amp or did you upgrade. I have a stealth 10 from my UTV that I took off as I kept hitting my head on it and it always drained my battery. Looking at installing it on my 242 LS. Also, which mounts did you use to affix it?

 

[cyclops]

I want to upgrade my sound on my 15' 242 LS.

Any chance you still have your OEMs and would sell me one or two that's in good shape? I just bought a 2015 242 LS and one speaker is blown.

 

[Hezi]

Any chance you still have your OEMs and would sell me one or two that's in good shape? I just bought a 2015 242 LS and one speaker is blown.

I tested the old speakers and seems to get 4 working out of the 6. Where are you from? Your profile is missing the info..

 

[Hezi]

Have you cut the ground lead in the headunit harness and connected the ground from the headunit to the 0awg ground block? This is what I mean by the same path. It does make a big difference and is what fixed the same issue for others.

I followed your advice this weekend and walla, noise is gone. Ugh! Only if I had this little piece of knowledge, I would save few hours of my own work and the half day off and $250 paid to authorized JL installer that ended up messing with the gain to lower the buzz.... Better late than never.

Thank you!

 

[Hezi]

Btw, I added second pair of mx650 to the tower, this one is facing forward. Since the tower is on its own amp (JL 4 channel, 2 bridged for sub and 2 for tower) with only 2 channels available, I installed in parallel and working on 2 ohms per speakers. Creative audio sale person and JL tech saying it's fine (although spec say speaker needs 4 ohm nominal) . If I had the foresight, I would invest in a 6 channel amp, but I didn't. What is the expert opinion in the matter? I am still planning to disconnect all the speakers wires from both amps and tune with AC meter to JL specs (as I did before twice before installer messed with it to lower system white noise, huge pain in the butt for a big guy like me in such small space). Do I need to compensate some how for the drop in ohm?

One last note; if I would to do this again, and would drop so much on a system, I would buy a pair of mx 770 and try to fit it in the boat speakers (ment for 650). They sound so much better and can last through lots more abuse. I think it can be done in all if not most positions around the boat. It needs to be tested and modified obviously, but I think it's doable. Worth the slight overall price bump for what you're getting. My personal opinion anyway.

 

[Mainah]

Btw, I added second pair of mx650 to the tower, this one is facing forward. Since the tower is on its own amp (JL 4 channel, 2 bridged for sub and 2 for tower) with only 2 channels available, I installed in parallel and working on 2 ohms per speakers. Creative audio sale person and JL tech saying it's fine (although spec say speaker needs 4 ohm nominal) . If I had the foresight, I would invest in a 6 channel amp, but I didn't. What is the expert opinion in the matter? I am still planning to disconnect all the speakers wires from both amps and tune with AC meter to JL specs (as I did before twice before installer messed with it to lower system white noise, huge pain in the butt for a big guy like me in such small space). Do I need to compensate some how for the drop in ohm?

One last note; if I would to do this again, and would drop so much on a system, I would buy a pair of mx 770 and try to fit it in the boat speakers (ment for 650). They sound so much better and can last through lots more abuse. I think it can be done in all if not most positions around the boat. It needs to be tested and modified obviously, but I think it's doable. Worth the slight overall price bump for what you're getting. My personal opinion anyway.

First a disclaimer for this response.... Tuning a audio system has many variables and can cause damage to equipment or yourself. I am offering the below as just a guy on the internet and assume no responsibility.

The JL manual will have different target volatges for different resistance (ohms). I know JL recommends 75% volume in the headunit for this but I did significant testing on the polk pa4a headunit with a tone generator app I tested separately for output out of the phone (function generator pro was the best of three apps I tested) on the different sources. The gain on the pa4a is no where close to linear. If you normally play music through usb I would play a 1k test tone at max on Connext and tune the amp to the jl manual target voltage which btw came out very close for me with oscilloscope tuning page one has headunit and page two has amps https://jetboaters.net/threads/polk-pa4a-oscilloscope-testing.16908/ .

If you normally play with Bluetooth or aux in then I recommend 95% volume on connext with the 1k test tone. Repeat for the sub channel with a 40 hz test tone to the recommend bridged voltage for given resistance in the jl manual.

When playing the test tones have both your phone and the volume controller in the app at max volume. Make sure power to the amps is off when connecting or disconnecting speakers or power wires. Make sure you are insulated from any leads on the amp and be careful not to brind the positive and negative leads. Start with the gains/input sensitivity all the way down on the amp with the speakers disconnected. After finished tuning do not exceed 98 percent volume for usb or 93 percent volume for BT or aux in. Keep in mind this is for the polk pa4a running through connext 1.0 with no external zone or eq controller like a ws 420. Also keep all the connext eq settings flat for tuning except for having loudness on.

When in doubt consult a professional but perhaps not the jl certified installer who has no clue about using the same path to ground to eliminate noise. Measuring clippling with an oscilloscope or smd is also better than the voltage method.

 

[swatski]

I followed your advice this weekend and walla, noise is gone. Ugh! Only if I had this little piece of knowledge, I would save few hours of my own work and the half day off and $250 paid to authorized JL installer that ended up messing with the gain to lower the buzz.... Better late than never.

Thank you!

That was my experience, too!
And I came to a point where I was almost resigned to live with the hum. Blamed the blowers.
That hum hunt thread where @Mainah posted on the grounding scenario is should be a FAQ if not already!

Man, it is so much fun to not have noise in my boat’s stereo and not to have to worry about it.

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[cyclops]

I tested the old speakers and seems to get 4 working out of the 6. Where are you from? Your profile is missing the info..

Southern Maryland!

 

[Jaylex]

@Hezi you are correct the larger 7.7s sound better and I can confirm that they do fit with virtually zero modification, only a 3/4 spacer for the area in the bow, and slightly enlarged holes in the other areas.

On my first phase 1 audio build I also went with 8 MX 650s, not loud enough, so sold those and picked up 8 JL M770s...and a second 800/8 to double the power.

LOUD is an understatement, and rarely need to go past 80%.

@Mainah i have the dreded noise issue in my system and plan on having my installer give the HU ground trick a try, sounds like a winner, I have a ton of noise when its at zero voulme. Would love to make that disappear.

 

[Mainah]

@Hezi you are correct the larger 7.7s sound better and I can confirm that they do fit with virtually zero modification, only a 3/4 spacer for the area in the bow, and slightly enlarged holes in the other areas.

On my first phase 1 audio build I also went with 8 MX 650s, not loud enough, so sold those and picked up 8 JL M770s...and a second 800/8 to double the power.

LOUD is an understatement, and rarely need to go past 80%.

@Mainah i have the dreded noise issue in my system and plan on having my installer give the HU ground trick a try, sounds like a winner, I have a ton of noise when its at zero voulme. Would love to make that disappear.


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The wires for your bottom amp running behind before going through the board hole it is not helping the noise situation. The switching power supply is right in that area of the amp and can cause noise to be picked up in the wires when that close to the back or front of the chassis in some cases. I would have the holes drilled so that the wires can exit just above the amp. Hopefully those orcas are shield too. The HU same path to ground is still the most important.

 

[Jaylex]

Im going to swap out the RCAs as well for the Knuconcepts (not sure which ones yet, suggestions?) to see if the ground and new RCAs does the trick.

Even if that kills 80% of the noise I would be happy, I have come up with workarounds but prefer to get a cleaner signal.

 

[Mainah]

Im going to swap out the RCAs as well for the Knuconcepts (not sure which ones yet, suggestions?) to see if the ground and new RCAs does the trick.

Even if that kills 80% of the noise I would be happy, I have come up with workarounds but prefer to get a cleaner signal.

I have the karma rcas and no noise but all of my wire runs behind the board help with that too. The Krystal rcas have the best shielding. I really would relocate the wires run along the back of the amp chassis. If your installer did it I would ask that they fix that for free. Especially since your are passing along the valuable knowledge that can cause noise and to same path ground the HU to eliminate noise (both of which they should have already known if a professional installer).

 

[swatski]

Im going to swap out the RCAs as well for the Knuconcepts (not sure which ones yet, suggestions?) to see if the ground and new RCAs does the trick.

Even if that kills 80% of the noise I would be happy, I have come up with workarounds but prefer to get a cleaner signal.

Check out this post - huge success based on @Mainah recommendations

Well... Success!!!

I finally got to it. So, after cleaning up the wires/common ground situation installing those Krystal KnuKonceptz RCAs made all the remaining hum/noise/crackling sounds DISAPPEAR!!!
View attachment 81023
View attachment 81022
The WS420 connections and under-the-helm interference must have been responsible for the noise.

What a relief... no noise, no hum!! Just great sound (or nothing).

My system would certainly not pass for a top tier, but with 10 Polk DBs (powered by two xc1410 clarions), tower ICON8s (powered with WS HT-2) and a powered Basslink subwoofer - all routed through the WS420 - I would consider it solid.

Sound quality is great, with no hum/noise no matter what other equipment is running (blowers, engine, ballast pumps etc.)
The system is loud, for in-boat listening becomes unbearably loud past about 50% volume (no distortion).

Me thinks this system is in my boat to stay!

Thanks @Mainah et al. for great advice here!

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[Jaylex]

Adding this to my list, @Mainah is there a diff between the two lines of RCAs you mentioned, worth getting the Krystal ones?

Also how do I know how many to order, we only have 2 RCA pre-outs, and I have 4 amps, I haven't looked to see how he has it all connected for the RCAs since its mostly hidden the way he made a float rack.

And how would we relocate the wires, instead of them going behind the amp, maybe to the side?

This guy will def take care of it, he was also annoyed at the buzz and due to time constraints I decided I could live with it until I got a chance to get take it back after the season.

With all these speakers and amps I rarely have it off to hear the hum, but sure would be nice to get it all cleaned up.

Will pass on the info to him and see how it turns out when I can get out there to have him install the push button start, LEDs, etc.

 

[Mainah]

Adding this to my list, @Mainah is there a diff between the two lines of RCAs you mentioned, worth getting the Krystal ones?

Also how do I know how many to order, we only have 2 RCA pre-outs, and I have 4 amps, I haven't looked to see how he has it all connected for the RCAs since its mostly hidden the way he made a float rack.

And how would we relocate the wires, instead of them going behind the amp, maybe to the side?

This guy will def take care of it, he was also annoyed at the buzz and due to time constraints I decided I could live with it until I got a chance to get take it back after the season.

With all these speakers and amps I rarely have it off to hear the hum, but sure would be nice to get it all cleaned up.

Will pass on the info to him and see how it turns out when I can get out there to have him install the push button start, LEDs, etc.

The holes are directly behind the middle of at least one of the amp chassis move them to coming out between the two amps. With 4 amps you need at least 4 sets of rcas. Given all the issues recently around noise I would absolutely go with the krystal rcas. As for the leds I would recommend that the controller be kept away from the hu/amps and on a different path to ground if pssobile as some have had issues with noise from leds.

 

[Jaylex]

Ok yep I can see in the pics now....they are going behind the amp.

I will ask him to move them out towards the sides more.....does he need to move all wires, or just power/ground??

Im pretty sure between that and the RCAs and ground HU I should be solid.

 

[Mainah]

Ok yep I can see in the pics now....they are going behind the amp.

I will ask him to move them out towards the sides more.....does he need to move all wires, or just power/ground??

Im pretty sure between that and the RCAs and ground HU I should be solid.

Moving all is what I recommend. As an example think about how an amp clamp works. An amp clamp is able to measure hall effect without ever touching the wires. Granted a hall effect sensor is more sensitive but amps amplify signals. If that signal is polluted even a tiny bit that pollution is being amplified. Atmospheric electrical radiation disipates greatly with distance as air is a poor conductor.

Yes after all of that you should have a very clean signal.

 

[Hezi]

Southern Maryland!

Sorry I didn't reply sooner. I want to get rid of all 4. Message me in private if interested