engine noise through tower speakers

Took the boat back to the dealer and they could not get rid of the noise. Any suggestions or can anyone recommend a stereo guy near yorba linda?

Thanks

Bad ground or gain too high.

In cars, sometimes you have to put in resistor type spark plugs, and that gets rid of the whining. Check one of your plugs, there should be an "R" in the plug model number.

If it is really engine noise, and not just hiss due to improper gain setting, the likely cause is that the radio and the amp see a different voltage and ground potential. Lots of times we see the radio getting its power from the helm wiring loom with a questionable ground and lots of other devices getting power off of the harness' B+ lead, includig many noise sources. The helm wiring harness is a pretty "dirty" place to get radio power.

Move the radio's power wire to the power input of your largest amp. Your red and yellow power wires go to your positive amp terminal , (the red wire needs switched) and the black goes to the amp's negative temminal. This puts the radio and the amplifier(s) at teh same vcoltage and groind potential.

More often than not, this will fix engine noise.

Phil
Kicker

The hiss is only there while the engine is on, goes away when I turn the motor off. Thanks for the tip, I'll try it tonight. So basically I'll just be powering the head unit from the amp? It is the jbl unit that came from the factory.
Thanks again for the input

Originally Posted by wakebrdr94

The hiss is only there while the engine is on, goes away when I turn the motor off. Thanks for the tip, I'll try it tonight. So basically I'll just be powering the head unit from the amp? It is the jbl unit that came from the factory.
Thanks again for the input

Not from the amp, but from the amp power wiring.... SInce it is connected to two big conductors tied staright to the battery, it should be cleaner. With some amps you get to take advantge of the big filter capacitor just inside the amp too, but that is not a prime reason for doing it.

You got the part about having the red wire switched, right?
Phil
Kicker

Dave your black box should already be wired up like Phil desribes above and pulling power and ground from the amps. If it is wired up that way all of the low hanging fruit is gone and it gets into tough troubleshooting and process of elimination. Make sure your battery terminals are clean and free of corrosion.

Dave,
There are lots of different types of noise. There is hiss which kind of sounds like a distant waterfall. There is a high frequency whine that changes pitch with the rpm. There is a tick that comes on with the ignition or accessory or when running. All have different causes and remedies. Maybe I missed it but could you clarify exactly what it is.

David
Earmark Marine

Originally Posted by david_e_m

Dave,
There are lots of different types of noise. There is hiss which kind of sounds like a distant waterfall. There is a high frequency whine that changes pitch with the rpm. There is a tick that comes on with the ignition or accessory or when running. All have different causes and remedies. Maybe I missed it but could you clarify exactly what it is.

David
Earmark Marine

Hi David, can you elaborate on the "tick that comes on with the ignition or accessory"? I've been chasing an intermittent problem that sounds similar. It is a continuous "tick tick tick tick" sound that has been un-affectionately named "the helicopter" by my crew

The noise itself is a high pitched static noise. However, I never realized it until you mentioned it. The noise is a constant, it does not change with rpm's. But it is only there when the motor is on.

Nu bu, just put in two brand new blue top optima's, terminals are clean

Phil, I got understood once I read it again.

Thanks so far for the advice

Dave and Shunra,
You are at a bit of a disadvantage as compared to a dealer because you don't have an endless inventory of equipment to rotate in/out of your system as a diagnostic tool. So you will have to use what is available.
First, even though a ground loop may not be the direct cause, you first have to eliminate it and low voltage by taking the steps referenced above by Phil and others.
Remember, that the helm buss ground and engine block to battery grounds and terminations are just as relavent to noise as is the stereo wiring.
Next, you've got to rotate your tower and in-boat RCAs plus rotate your amplification in order to determine that it is or is not an equipment problem. You may have the noise in the boat but the tower speakers may be better equipped to expose the noise. So put your ears directly to the in-boat speakers with the amplifier gain turned up a little. If you have to, pull a tower speaker down and temporarily hook it up in a coaming location. In any case, sequentially isolate and confirm each component individually in the signal path. Don't hesitate to break the system down to the simplist configuration without noise and add one component at a time until the noise reappears somewhere. You have to find if the noise is a result of faulty wiring, equipment or the boat. Narrowing down the wiring and equipment through a process of elimination takes a little effort but is easy. Quit stalling and get to it. If you determine that its an engine management module then that will be fixable but a real pain to isolate.

David
Earmark Marine