Speakers pop when wakeplate is used

[WakeProdigy]

Ok, so I picked up my '05 21V last week from the dealer. They were having problems with the speakers outputting a popping sound when the hydraulic wakeplate is moved. They couldn't figure out the problem, but upon looking at it I saw multiple things that could have caused the problem.

1) The Audio cables used to send the signal to the amplifier are low grade and lack the proper shielding needed for high quality sound.

2) The Audio cables are wire-tied together with the power and ground wires. This is a bad installation method because noise in the power line can be picked up by the low-grade audio cables used.

Without spending money for new cables and wasting time rewiring the system, has anyone experienced this problem? If so what did you do to fix the problem.

Thanks,
Tom

[Jon]

The popping is coming from what you said you said, the stereo cables are running along with pos. and neg. cables. You could re-route the rc cables around the bow of the boat and not along the + and - cables.

Thanks,

I started to reroute the wires today...what a pain in the butt! There are so many wire ties and tight spaces. It looks like I will also have to buy a new set of cables because the ones that came wired with the amp weren't long enough to take around the bow. I should get a free pair of tower speaks for doing this

[nani]

My 05 21v does the same thing, and my amp cables are not run along the power lines.

I just added it to the list of things for the first service.

[DKJBama92Mariah]

Tom,

Welcome to the board. Its a pretty friendly community and most members are more than willing to help out if they can.

I've never dealt with a complex marine audio system, but i had several systems in cars when i was youger. Maybe thats by i cant hear so well now.

I dont think the "pop" you are describing is likely to be caused by the power and ground cables being next to your patch cables. Yes, it is not advisable to have them next to each other, but the noises induced by this situation are not typically a pronounced pop.

My gut tells me you have a problem with your grounds. If either your cd player or amp shares a ground with the hydraulic motor, it could very well induce this type of pop into your system. Before going for a full fledged fix, you will want to test this theory. I would run a temporary wire from the ground wire of the cd player directly to the negative post of the battery. Hit the trim tab switch and see if you still have the pop. If its still there, try the same procedure for ground wire on the amp. For purposes of just testing this on the amp, i dont think you need ot go full fledged 4 guage wire; you can probably get away with 12 guage so long as you dont blast the system or run it more than a minute or two. If this turns out to be the problem, then run a dedicated wire (of the appropriate guage) directly to the negative battery post. I wouldnt advise grounding to the engine block b/c this could cause another problem called ground loop which induces an alternator whine into the system.

If none of this helps, there is one other thing you can check. Make sure that the ground portion of your RCA patch cables isnt touching anything metal behind the dash (such as the backing plates that hold the guages in). If this is happening, it can cause all sorts of sound quality nasties.

OK, thats it, thats pretty much all i can remember. Too much jim beam in college years past makes the memory fade.

If you still cant rectify the problem through the dealer or advice on this forum, you might also try the discussion forums at http://www.wakeworld.com . There is a dedicated A/V forum on that board and the (much larger) membership probably has MUCH MORE combined experience with this type of thing than anyone here does.

Good luck and keep us posted.

Cheers,
DKJ

DKJ,

I originally thought that the "pop" was also due to the trim sharing a ground with the audio system. When I mentioned this to the service guys they said that they checked that and it wasn't a problem. Also, I don't believe it is a grounding issue, because when I take the amp out of the system and use the trim, the speakers that are powered by the head unit do not produce the popping sound. And, it isn't a grounding problem with the amp either because the amp is grounded directly to the neg. terminal of the battery. All of this still leads me to believe that the problem is with the patch cables running along the power/ground wires. The patch cables run directly parallel with the power and ground wires for the system, not the power/ground for the amplifier. So, when the trim is turned on the current in the system power/ground wires changes and due to fundamental electormagnetics (you know voltage is equal to the change in flux with respect to time, and as current changes so does the flux) current is induced in the patch cables running physically in parallel to the power cables. This makes sense because at low volume levels the "pop" is well pronounced, but at higher volumes the signal level is much higher than the "pop" level, and the pop can no longer be heard.

Theoretically if the patch cables crossed the power/ground wires perpandicularly no current would be induced in the patch cables...so as a side note, if anyone reading this ever has to cross their signal wires with their power wires try to do it at a 90 degree angle... enough with the EM review.

Still haven't finished rerouting the patch cables. I let you all know if it helps.

Tom

DKJ,

I originally thought that the "pop" was also due to the trim sharing a ground with the audio system. When I mentioned this to the service guys they said that they checked that and it wasn't a problem. Also, I don't believe it is a grounding issue, because when I take the amp out of the system and use the trim, the speakers that are powered by the head unit do not produce the popping sound. And, it isn't a grounding problem with the amp either because the amp is grounded directly to the neg. terminal of the battery. All of this still leads me to believe that the problem is with the patch cables running along the power/ground wires. The patch cables run directly parallel with the power and ground wires for the system, not the power/ground for the amplifier. So, when the trim is turned on the current in the system power/ground wires changes and due to fundamental electormagnetics (you know voltage is equal to the change in flux with respect to time, and as current changes so does the flux) current is induced in the patch cables running physically in parallel to the power cables. This makes sense because at low volume levels the "pop" is well pronounced, but at higher volumes the signal level is much higher than the "pop" level, and the pop can no longer be heard.

Theoretically if the patch cables crossed the power/ground wires perpandicularly no current would be induced in the patch cables...so as a side note, if anyone reading this ever has to cross their signal wires with their power wires try to do it at a 90 degree angle... enough with the EM review.

Still haven't finished rerouting the patch cables. I let you all know if it helps.

Tom

[WakeProdigy]

DKJ,

I originally thought that the "pop" was also due to the trim sharing a ground with the audio system. When I mentioned this to the service guys they said that they checked that and it wasn't a problem. Also, I don't believe it is a grounding issue, because when I take the amp out of the system and use the trim, the speakers that are powered by the head unit do not produce the popping sound. And, it isn't a grounding problem with the amp either because the amp is grounded directly to the neg. terminal of the battery. All of this still leads me to believe that the problem is with the patch cables running along the power/ground wires. The patch cables run directly parallel with the power and ground wires for the system, not the power/ground for the amplifier. So, when the trim is turned on the current in the system power/ground wires changes and due to fundamental electormagnetics (you know voltage is equal to the change in flux with respect to time, and as current changes so does the flux) current is induced in the patch cables running physically in parallel to the power cables. This makes sense because at low volume levels the "pop" is well pronounced, but at higher volumes the signal level is much higher than the "pop" level, and the pop can no longer be heard.

Theoretically if the patch cables crossed the power/ground wires perpandicularly no current would be induced in the patch cables...so as a side note, if anyone reading this ever has to cross their signal wires with their power wires try to do it at a 90 degree angle... enough with the EM review.

Still haven't finished rerouting the patch cables. I let you all know if it helps.

Tom

[DKJBama92Mariah]

Tom,

Rule number 1. Don’t always take what the dealer says as gospel. Yes, they work on the boats all the time, but that doesn’t mean that they can’t be wrong.

Come the end of the day, you may very well end up being right. I just want to offer you all the diagnostic procedures I can before you tear your boat apart rerouting cables for something that might not be the problem. There are several procedures you can follow to isolate the source of the interference.

1. Disconnect the RCA patch cables from the CD player and leave them hooked up to the amp. Power the system up and hit the trim switch. If the noise is still there, then you know it’s not coming from the preamp stage of the CD player.

2. Reconnect the cables to the CD player and disconnect them from the amp. Again, fire up the system and hit the trim switch. If the noise is gone, then you are correct and it is being introduced somewhere along the path of the patch cables from the CD player to the amp. If the noise is still there, then you KNOW it’s not your cables and we’ll keep going. If it is the cables, then I’ll get to that in a minute.

3. If the noise was still there in step 2, then your interference is being introduced either in the amp or in the speaker cables running from the amp to the speakers. Assuming that the amplified speakers are on your tower, and that the tower is grounded to the electrical system (perhaps for lights???) a chafed speaker wire contacting the tower could possibly be contacting the tower and causing the noise. This is unlikely, however, because the noise wouldn’t be strictly when you activate the trim tab. It could also be coming from the amp itself, which would mean that the hydraulic pump is dirtying up the supply of power and causing the noise.

Ok, if you have isolated the noise to the cables, then there are a few things you should consider. It is not ABSOLUTELY necessary to isolate the patch cables from the power cables. Yes, for maximum audio quality, they should be kept apart, but a ski boat is hardly an anechoic chamber and since the power and ground cables are running directly to the battery, the battery itself will isolate most, if not all, noticeable electrical noise between the different components connected directly to it.

The fact that the noise is only present when you operate the hydraulic pump, and not any other electrical device, leads me to believe that the noise isn’t being introduced into the patch cables from the amp power and ground wires. Now, if the patch cables get anywhere near the power cables for the pump, then that could very likely be the source of your noise. If the cables are near the relay for the hydraulic pump, then the spark in the relay when it closes would DEFINITELY create RF interference that would lead to your noise.

If you’ve isolated the noise to the cables, here is what I would do before I started tearing the boat apart to reroute the cables. Go to walmart and buy a cheapo set of patch cables. You can return them when you’re done and get some quality ones at an audio shop if you find that you need them. Don’t install them into the boat. Just hook them up to the CD player and amp and drape them across the boat. Now check to see if it still makes the noise. If it still does, it is unlikely that moving the installed cables will help. If it doesn’t, then start moving the cable around the boat trying the trim switch with the cables in different places to see if you can find where the noise is coming from.

OK, that’s all I’ve got for now. It would help if you could clarify the nature of the noise. Is it a single pop that happens just when you hit the switch, or is it continuous the whole time the switch is pressed? Also, is a pop, or more like a crackle, buzzing, or whirring noise?

Also, if neither you or the dealer can figure it out, just drag the boat down to a car audio shop and let them listen to it and tell you what they think. They know a whole lot more about this stuff than you, me, and the dealer combined.

Good luck

Cheers,
DKJ

[DKJBama92Mariah]

Oops, Sorry Tom,

Guess I should have read your reply carefully before drafting 1000 word essay of a response. I didnt catch that the patch cables were run next to the power wires for the hydraulic motor. I guess i just assumed it was the power wires for the amp. However, you might still consider trying the diagnostic procedures in the previous post to be completely sure that the proximity of the two sets of cables is what is causing your problem before ripping the boat apart.

If the wires are not visible, then there is a cheap fix, but it is kinda ghetto. You can wrap the patch cable in aluminum foil for the length of the run that it is next to the power wire for the trim pump. The foil will shield the cable from the EMI from the pump wires.

I'm not familiar with the wiring layout of your boat, but if you could get about 6" of distance between the two cables, it would probably eliminate, or at least reduce the interference.

I dont know about you, but if I had just dropped $45-50k on a new boat, I probably wouldn't do the ghetto foil fix. Considering what you have in it, i wouldnt hesitate to drop $100 on a good set of patch cables to do the job right. With good shielded cables, you shouldnt have any interference problems unless the cables are actually bundled together with the offending circuit.

If that turns out to be the solution, I dont think it would be unreasonable to ask Skier's Choice ot foot the bill for the new cables. Especially considering that they should have used better cables to begin with if they planned to have signal cables and power cables running in close proximity to each other. After all, we ARE talking about a boat with a purchase price that would make one helluva down payment on a home, not an $8k flatbottom puddle-jumper.

Man, i dont know whats up with me. I seem to be unconscionably verbose today. I just wish i could write this much this quick on an exam.

Good luck, and let us know if you find the problem and how you end up solving it.

Cheers,
DKJ