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Interference on tower speakers


Northern Exposure

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This has been an issue right from the start. There is a hissing/humming sound coming from the tower speakers when motor running. If I am sitting out on lake chilling, no humming. Dealer has said they have done all they can. It is annoying to say the least. Anyone else have this issue or recommend anything? It is the stock RF amp and the Wetsound tower speakers. There is no humming from cabin speakers though. Keep it simple as I am technically challenged when it comes to electronics. Thanks Northern

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Could take a long time to debug.......

I have a detailed post on Malibu 10KHz tone isseu but its in the maintenance section. #528616

High Pitch 10KHz noise on stereo. Think its the ETC.

If it is the same issue, then its probably because your tower amp/RCAs are closer to battery and picking up noise. Is the noisy amp and its RCAs closer to the battery which connects to the ALT GND? If you have an iPhone, then buy the spectrum analyzer app which I have and see if the noise is 10KHz tone. If it is then that's the issue. I also found out my better JL amp picks up more noise than my cheaper amp.

If its not 10KHz, then it could be a ton of things,

1) RCA bad

2) bad ground. Best is having amp GND and stereo GND connected with nothing else connected on this GND. Same with power.

3) amp gain too high

4) RCAs way too long

5) RCAs near battery

6) long bat pwr/gnd creating magnetic fields Take the amp RCAs and move them around near the batteries and see if the noise changes..

During my debug I was amazed as how much noise can get injected just by changing some simple things. Like moving amp ground from one battery to another battery even though the batteries were connected with 2.5 ft 2 gauge wire. Or by moving amp power from one bat to another bat.

Malibu should re-design the boat and have the amps like 3 feet from head unit and not 10 feet away and right next to batteries.

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Very, very few people have this specific noise as described above by JM. But it does exist in a select few boats. A similar engine management issue is found in particular models of Supra also. Those with considerable hearing damage from listening to loud music may not even hear it depending on the intensity in various boats. But if you do hear this type of super high frequency noise that does not vary, it's way beyond annoying. It should be there the minute you turn on the boat ignition/accessory even before it is running. And once introduced into the boat wiring system it's transmitted by everything. However, you do not usually have to move the electronics as you can often filter the noise at the source in the engine compartment.

David

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jkendallmsce

Do you have the jbl black box??

If so, I had/still have just better the same problem. In fact I am up to the 3rd-4th black box on the boat. Ya loose track after the 2nd.

I would get a buzz only with engine running. and would not change pitch as RPMs changed. There was a very small buzz when not running, but as soon as the engine fired up, it was like a swarm of mosquitoes/birds were in the boat with you.

Malibu first said it was incompatibilty with the JL audio amps and Boston Pro speakers.....really!!!

Finally some inline filters were installed that helps, but does not totally correct the problem. Don't know what kind of filters they are.

One big problem is the inablility to properly ground the jbl black box. I have the ground going directly to the same battery powering the amps. May be one of the reasons why Malibu switched to the Rockford Fosgate unit.

Edited by jkendallmsce
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jk,

It's natural to ground all electronics at the battery. However, technically the ideal reference point for ALL electronics in the signal path should be the shortest path between the audio electronics themselves. This means that both the source electronics power and ground should be accessed as close as possible to the primary terminals of the largest amplifier. This would include the HU, ipod supply, EQ, everything. There are many other steps but this is the first and most important one in noise elimination.

David

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Thanks for the responses. Been busy with work so never got back to site. The humming doesn't change with engine speed. Any gains are still factory set. The setup is from factory with R. F. equipment so that hasn't changed. I do believe it is R.F. black box. I will try and get out this weekend (weather is not looking so great) and check over a couple of things that was suggested. One of the things I was wondering, could it be the amp? I quess I was thinking to try another amp to see if same results. But I will check the advise first before anything changes. Thanks Northern.

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Unfortunately the dealers are not stereo experts. As you know Wizard uses Tuskey out of Rocky..you can try him or if there is a good stereo shop around Edmonton give them a try. I use Mobile Sounds out of Calgary. It is a two man shop and the owner has been in the industry for years. He will get your problem solved but it will cost of course. PM me if you want contact info. Rob

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I quess I am refering to the head unit undrneath. I think they refer to the touch pad at the driver a "remote". Sorry for confusion. Northern

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Very, very few people have this specific noise as described above by JM. But it does exist in a select few boats. A similar engine management issue is found in particular models of Supra also. Those with considerable hearing damage from listening to loud music may not even hear it depending on the intensity in various boats. But if you do hear this type of super high frequency noise that does not vary, it's way beyond annoying. It should be there the minute you turn on the boat ignition/accessory even before it is running. And once introduced into the boat wiring system it's transmitted by everything. However, you do not usually have to move the electronics as you can often filter the noise at the source in the engine compartment.

David

Hi David,

Are you specifically saying that you know people that had the ETC 10 KHz noise issue and they filtered it out in throttle motor control in engine? If so then please provide the details of the type of filter and where it was placed. The source of Malibu ETC noise is embedded within the ETC throttle motor and there's no way of getting inside the throttle motor. I have grounded the housing and grounded/shielded the ETC wires with no luck. At some point I am ordering ferrites that are spec'ed in the 1MHz, 5MHz, 10MHz, 100MHz plus etc range etc and try out (as electronics stores dont spec the snap on ferrites so you need to special order). If someone already did this then would love the details.

Thanks

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I had the same issue with all my speakers not just tower ones. Pulled the radio and cut the ground...ran a heavier wire as the ground to the grounding block under the driver dash...and guess what no more hissing and annoying noise coming from the speakers. Fixed my problem hopefully will fix yours. Let me know if you need anything else.

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