Just installed mine, and having some trouble.

Getting an engine whine from all the speakers. I ran the power wire from the battery through the firewall and down the driver's side of the car to the trunk. I put the ground in the trunk for all three amps. Ran the signal wires down the passanger side of the car and kept all signal and power wires seperated from each other. the only thing I can think of is the whine is coming through the power or ground wires Any suggestions. Where did you run the power wire through the firewall. Where is the ECU, maybe I have the wires too close to that?!

Any suggestions. Have tested the patch cables and it is not coming through there. Have tested the speaker wires, and no whine. Where did you ground the amp wires?

Help please!!!

Thanks

John

 

I had the same trouble in my 200SX as in my Maxima. If you're using an external amp for the mids and tweets, you may have the gain set too high. I have a JVC amp (just for the mids and tweets - all others parts are Kenwood Excelon. the JVC is the first thing to go, and very soon!), and it's power distribution is probably cheap, so I had to turn down the gain and turn up the volume. A better amp (a la Excelon or Fosgate) will probably fix the problem, but the gain decrease will help for now if you're experiencing the same problem that I am.

 

Sounds like you have ground loop. Are all the amps grounded together? How did you run the wires to the ground point? I personally would buy a distribution block and run the wires to it and one big wire to the grounding point. If this is what you did, then I would see where the patch cables are running. They might be close to another power source that is emitting the whine. If all else fails, you could try the local stereo shop. Hope this helps!! Good luck!!

 

I've got a fosgate amp and I'm getting engine noise too. I'll try turning the gain down.. that's the first time I've heard that. Otherwise I gotta re-route my speaker wire or my power cable.. their about 1 foot apart.

 

I need a little more info. For instance what brand of amps do you have, because someone said it might be the amps and yes it could. Also it could be that you routed the ground, power, accessory, speaker wire all on one side of the car. You don't want to do that cause (I think) it causes interference. It could be the RCA cables, what brand. Someone made a point that it could be that you have all the amps sharing a ground or grounded together. From personal experience I've done that and don't recall experiencing alternator whine. It could be that you need to sand the area you chose as your ground. It could be any of these things. I noticed that alternator whine was due to the head unit (bad RCA inputs). I'll be happy to help as much as I can. Though it's been while since I followed car audio. Hope this info helps.

 

The amps are MTX. I ran the all power wires on the driver's side of the car, and all signal wires down the passenger side. Yes if you run your power and signal wires too close together the magnetic field the power wires creates can cause interference.

All the amps share a common ground. I did sand the area down.

Does anyone have the service manuals? I've heard that those tell you a factory ground points. I know a factory ground point should not have noise.

Turning the gain down can help, but most of the time you just turn down the wine if it's coming out of the patch cables. To set your gains there is a specific way. You turn your gains all the way down, make sure bass and treble features are at zero or not changed from "flat." Now turn up the headunit till you hear distortion, or till clipping occurs. Once you hear this back down just a little off the volume. Now go to your amps, turn up the gains till clipping occurs there. Back off the gains just a little. Now your system is balanced. You do this b/c the volatage from the preamps varies with the output volume. By doing this you get less Hissss from you speakers and gives you the best power handling. This also keeps your amps safe, assuming you aren't trying to overpower them, from being overheated. If you don't believe me, ask a local stereo shop, or check out crutchfield, they'll tell you the same.

Now back to the engine whine. I have tried everything to get it out, but I think I getting it from my power cable. I think I may have run it close to something in the engine bay, but don't know what.

Any other thoughts? There's a chart that you can follow to diagnose noise, and I've been through that twice, getting different results everytime!

Well I'm agonna just keep tinkering w/ it and see what I can't find.

 

I don't think it has to do with the amps. I didn't have any amplifier on my kenwood excelon reciever powering sony explodes in all the doors and i got the same whine.

 

This is common in all Nissan vehicles. I have had several and have had systemds in all of them and there are two ways to solve this annoying problem the right way. The first and lest expensive step is to get a Noise Suppressor. You can get them at any Car Audio store, they run 10.00 to 35.00 dollars. The more you spend doesn't equate to better. The second cure is to switch to balanced interconnects (Balanced RCA cables) this eliminates all most all sound picked up by the stereo.

Running the wires through your vehicle separately only ensures that you will not get noise from the wiring itself.

good luck, and always ground to bare metal! with the ;argest, shortest ground wire.

Don

 

I'm running MTX amps in my car to and I have no whining what so ever. What type of power cable do you have? I have a 4 gauge monster cable that is powering my amps. Those cables have a thick layer of rubber that surrounds the cable. Running cables next to each other shouldn't be the problem if they are properly insulated.

 

hrmm.. I tried a noise suppressor and it seemed to get worse. What is a balanced RCA cable? what's the difference between it and a normal RCA cable? I used a fosgate wiring kit, I assumed the RCA cables would be high quality... was I wrong? my ground is about 18" is that too long?

 

There is no limit to saying what is too long for a ground wire (except for maybe 20 feet). The shortest possible length is the way to go. If you can shave off another 6" off the ground by relocating the ground, then that is best but that does not mean that the 18" you have is bad. unplug all the wires from you amp except the power and ground wires. noise still there? Now vice versa, take out power and leave in signal. noise still there? you keep doing this till there is no noise. when you reach that point then, you work your way back one wire at a time till the noise comes back. Then you know where its coming from.

Yes, running your power wire next to the signal wires is a good way to get noise into your system! The physics of it is simple. As current runs through the power wires ir creats an electromagnetic field. This field changes in size and strength in relation to the current supplied. Example, as the engine revs up more current is supplied via the altenator and that increases the whine and varies the frequency in which you hear it. If you have run your power and signal wires together and get no noise, you are either lucky, have an noise suppressor, or good shielded rca cables! If the suppressor and cables don't apply to you, will you come down here and buy a lotto ticket for me?

I had the stereo shop run all the wiring for me and I think they may have kinked the ground cable. That kink will put a whine in it everytime. I am going to wait till this weekend and rerun all the wires myself with a set of good shielded rca's and thicker power cables. If it works I'll keep you posted.

 

Did you ever solve this problem with the whining noise in your radio??

 

kinda, but not really. I have figured out that it is in the amp rack design. From the way MTX does their power, speaker, and inputs on the amps, they are too close. I am in the process of making a new amp rack that will solve this. This includes selling my MTX amps and replacing them with PPI amps. These will be done different with an entirely new design.

 

You din't say it but I want to make sure...you do have a gromet in the firewall right and a fuse after the battery on the powerwire before it gets to the firewall right?

As for the noise. make sure there are no bare wires anywhere. Take the grounds and redue all of them. Instead of grounding them in the trunk you can do them to the seatbelt harness bolt or under the car to the frame. Make sure the rca's are good. Also make sure you have the proper size power/ground wires as well as proper speaker wire size. And no loose conections. Try all that if that works great if not come on back.

 

Everyone here has given good advice. Make sure your power cables and signal cables are ran separately and if they do have to cross paths that they do so at right angles to each other. Yes, make sure you ground all your amps to a common point to BARE metal. Try another grounding point, maybe the place you've used is a poor ground. The floor of the trunk should be a good place. Always use the same guage or larger ground wire as the power cable, as SHORT as possible. Come to think of it, use the largest you can find. Try a 4 guage. Less than a foot is the best, but not the absolute rule. Buy the most expensvie RCA cables (shielded) you can afford. Balanced cables are very good but you need amps that can except them, and not too many do. How many volts is your head unit putting out? The more the better. Higher voltage head units means less noise in the system. 4 volts seems to be good starting point, some are 5, and some go up to 8 or 9. If you have at least a 4 then you SHOULD be okay. This works because the higher the voltage the head unit puts out the lower you have to turn the gains up on your amps to get the desired volume. Noise suppressors are a great idea but you should try and fix the problem as well as you can first. You can also try a ground loop isolator, also at Radio Shack I believe. Ground loop isolators help a system where multiple grounding points are used. It sounds like this doesn't apply to you, but maybe you can read the literature that comes with it before you buy one.

Good luck. Hope this helped.

Tony

 

thanks for everyone's input on this matter. if you notice it is way back from april though. it is not a new occurance. I have streetwires zero noise cables. the power wire is going through a grommet, and is fused at 12 inches from the battery. The power wires (all of them) on the driver's side. The signal cables (all of them) are down the passenger side. I have checked, rechecked, and moved the ground.

Like I said before ... it is in the amp rack design. From the way MTX has their inputs there is noise introduced there. If I take my amps off the rack and just set them apart on the trunk floor no noise.

That is why I say that I am going to redo the amp rack and install new amps.

Thanks for the suggestions though.

 

IN the amp rack design? Meaning your amp rack? What is it made out of pure metel? Or are you trying to say that it's in the way mtx built there amps. This is real odd. I know alot of people that have mtx amps and even I once had mtx amps and never ever heard of noise going away like that.

 

no it is made out of wood, but the power wires to one amp are almost (I mean like 1 cm) away from the RCA cables on the next one. It is because they are side by side. If I were to stagger them like -_- then they would most likely be fine. If I felt like taking everything apart I would take a picture for you. Just trust me.

 

That shound't cause it at all. Many amps have inputs for power wire and rca conections on the same side and there fine. The wires are shielded and just cause they come close to each other at that point doesn't mean that it should cause it. Maybe in your case it does. But it's damn odd.

 

Something i would try doing is putting a piece of rubber between the screw and where it would mount the amp. It may help. I know that in some cases when using Kicker amps and you were to loose the little rubber pieces where the screw holes are then that can cause noises as well. Has something to do with the way the amp is grounded.

 

ummm, they are mounted to wood ... in contact with no metal whatsoever so that would not help.

 

I agree ... never had that happen before. But it only happens on two of the amps. the two that have the connections that close and the third amp on the end has no noise problems. And when I can take them off the rack and spread them out more to where the connections are not so close and resolve the problem I think I have figured out what causes it.

 

I don't disagree with your logic. It's just so damn odd.

 

IMHO, you're having ground problems. Just think - your amplifiers amplify signal relatively to their input ground, which is the trunk, unless that model has optical separation. The unit produces signal relatively to it's own ground. So, what you're actually amplifying is the head unit signal plus difference btween trunk ground and head unit ground. I actually helped my friend to do aftermarket upgrades twice - for his old 240SX and WRX. In both cases, to minimize that effect we used separate cables for amp ground and power and connected both of them directly to the battery. The level of mechanical noise from WRX's CD changer now is way higher then noise from amplifiers at full volume, no engine whine whatsoever. This ground wire to the amplifiers should be put near power wire to bring the total electromagnetic field from them to near zero since their currents go in opposite directions.

Mike.

 

So are you saying that we should consider putting the ground wire on the negative terminal of the battery? Sorry, I'm a little confused.

 

Sorry for stepping on toes here, but the ground wire should be as short as possible.

Tony

 

Short to what point? I mean, that yes, ground wire between head unit ground point and amplifier ground point should be as short as possible but not the wire from battery to the body of the car - that doesn't matter that much, since body of the car can be quite "dirty" ground. All electrical stuff uses body as the ground wire, and it's ok since all it interested in is mostly resistance. For sound purposes you need to provide "clean" ground, with the noise value less than 1mV, which is impossible without dedicated ground wire if you put amp in the trunk and that amp doesn't have optically separated input. It can be done also if you use high-level output of some aftermarket head unit and divide it's output signal directly in front of your trunk amp, meaning that you also dividing level of noise with the same proportion. The last variant is not that impressive from the sound quality point of view but at least you'd have low noise level.

Mike.

 

Just to add my 2 cents: If I understand it correctly, a ground loop situation usually occurs when the head unit (really a pre-amp) is grounded at a point different from where the amplifiers are grounded. The loop occurs because of the electrical differential and signal variances between the two grounding points.

The last time I performed a car stereo upgrade was when I wired up an ADS 6 channel amp in my last car. I ran an 8 gauge power feed from the battery, through the dash and tapped into it for the head unit. I then continued the power run to the trunk where the amp was mounted. I then took a second 8 gauge cable, to be used for grounding, and attached it to the SAME stock ground location for the head unit behind the dash. I also ran this grounding cable back to the amp in the trunk. I never had any engine noise or whine whatsoever. I did not use a ground loop isolator nor did I use a noise filter.

I am not sure I understand the logic of having a ground cable that is any larger than the power cable. I also do not understand the logic behind having the "shortest" possible ground cable - it shouldn't really make any difference. Just think about how any other electric device in your car is wired . . . Ground cables are run to most devices through the wiring harness . . .

If you're really worried about having the shortest possible ground wire for your amps, you could simply connect the head unit/pre-amp ground cable to the ground point in the rear of the car. In so doing, you should also resolve any risk of a ground loop since only one ground point is being used for all devices in the system.

 

- if I recall correctly "ground loop" actually stands for the closed circuit of ground wire which can cause some problems if placed in alternative electromagnetic field. Somehow this term is used for describing completely different problem but it's only the name, right?
The description of the problem is correct though.

- that's correct too, except two things - it's not necessary to take special care about power wire of the head unit, you can leave it as is. Another consern is that some guys put something ~1kW amps in the trunk which consumes up to 100 ampers in pulse. It simply may be too much for the ground point of the head unit. It also means that power/ground wires for trunk amps and their connections need to be done in the fashion similar to starter power wires and don't forget to place HUGE fuse somewhere nearby your power connection point, those wires can melt the car down .

- that's possible, except that high current issue I've already mentioned - it can reduce the power voltage supply on your amps due to some voltage drop on the body of the car under high current pulses. That's why we used the battery "-" terminal as our ground point. In ideal case, you're right, we needed to move head unit ground all the way to amp's ground in the trunk but that simply wasn't necessary.

Mike.