# "Whining" sound when accelerating



## thapranksta

I hooked up my first sound system recently. I got three issues:

I have a hissing sound coming out of my tweeters and my gain knob is just a little over 1/3 of the way. I mentioned this in another thread as well but it may be relevant.

When I accelerate, I hear a "whining" sound coming from my car. I know that it is coming from the speakers (probably tweeters again) because when I undo the preamp outputs the sound goes away.

My last problem is that so far I am not getting the great sound I expected from my speakers.

What do you contribute to these problems? My novice installation, cheap amp, or this is all normal? Thanks a lot.


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## aneonrider

Need a better ground for the amp... you are experiencing alternator whine.


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## thapranksta

How do I get a better ground? Just find a bolt that's better grounded and ground my amp to it? Make the ground wire shorter?


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## blacklabel

drill a new hole on the chassis of the car, sand it down to the metal NO PAINT and ground it there. also, i wouldn't run my ground wire longer than 1ft. if you do ground it to an alreay existing hole, just make sure that you shave/sand the paint away.


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## audioman42

what hu & amp are you using? where did you mount the amp?


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## rekd0514

We got rid of it in my brother's car by changing the ground location. The ground he had for his 2 amps were in different locations, but just the 4 channel he had was making noise. As soon as we moved its ground to a new spot it was fixed. I am not really sure why because it seemed like a good location and the ground was definitely sanded down.


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## thapranksta

I'm using a Kenwood DDX6019 HU (DVD/CD/etc.). I'm using a Blaupunkt THA275 amplifier 75 x 2 Watts. I using Polk DB6501 components 100 x 2 Watts. The amp is mounted underneath the driver's seat. I have it grounded in the B pillar close to where the seat belt is located. The place I grounded the wire has no paint at all. It appears to be completely metal. 

I'm not sure but I think my ground wire is actually 3 feet long (according to cardomain). I bought one of the Kicker kits and never shortened the wire. I figured it was already short enough. Could that be a problem as well?


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## kimokalihi

Also, is your RCA near your power wire at all? This will easily cause alternator whine, which is what you're experiencing. This happened to me with some cheap RCAs a while back. At first I thought I had a vacuum leak and I couldn't understand why I couldn't hear it under the hood. Don't remember how I found out it was the speakers, but it's a thing of the past now.


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## thapranksta

Yes, the RCA is right by the power wire. I started another thread a while back and mostly everyone told me that running wires together was fine. Now that I think about.....you was one of the guys that said it might possibly be a problem. Currently all my wires are running together.

Also, is having a 3 foot ground wire OK?


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## RMAT

chasm said:


> drill a new hole on the chassis of the car, sand it down to the metal NO PAINT and ground it there. also, i wouldn't run my ground wire longer than 1ft. if you do ground it to an alreay existing hole, just make sure that you shave/sand the paint away.


^^^needs to be less than 18 inches from what I've been told or as short as possible^^^

and it's not a good idea to run the rca's or speakers wires near the power wires.


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## thapranksta

I'll buy a set of RCA's from Wal-mart or somewhere to test it out. I'll just run them from the amp across the center console to the HU to see if the whine goes away. If the whine doesn't go, I will experiment with the ground. First seeing if I can find a better ground source and also shortening the wire if need be. I've got until after 4:30 before I get back to my system. Work sucks.  

All my wires except the ground are tied together or wrapped with electrical tape so if the power is causing interference I've got a little strenuous work to do.


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## aneonrider

RMAT said:


> ^^^needs to be less than 18 inches from what I've been told or as short as possible^^^
> 
> and it's not a good idea to run the rca's or speakers wires near the power wires.


18" is just an arbitrary number.. as long as it is to a good grounding point, the length really doesn't matter.

And the second point is one of those god awful myths.


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## chad

aneonrider said:


> 18" is just an arbitrary number.. as long as it is to a good grounding point, the length really doesn't matter.
> 
> And the second point is one of those god awful myths.


And to think in this thread we want the ground as close as possible but last week some wanted to run it clear back to the battery


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## thapranksta

^What do you think it is Chad?


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## durwood

chad said:


> And to think in this thread we want the ground as close as possible but last week some wanted to run it clear back to the battery


LOL.


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## durwood

I was waiting for this. Not all amps are created equal (input section) and not all rca's are shielded properly. I try to avoid problems. I'll run rcs going to a sub amp down the power side, but never run rcas used for full range down the same side as power wires. I just didn't feel like joining that discussion before. I'm going to get some numbers later here with an alternator and shed some light on this for some people, lucky for me we test alternators here at work.


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## 02bluesuperroo

I have all my wires run together for a time in my trunk and I have no problems. In fact, I have never experienced any problems running the wires together before as long as all the wiring was of decent quality. 

I would suspect the ground before anything else. I also wouldn't worry about keeping your ground wire the length it is but you might as well make it as short as possible to have it reach your intended grounding spot.


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## aneonrider

durwood said:


> I was waiting for this. Not all amps are created equal (input section) and not all rca's are shielded properly. I try to avoid problems. I'll run rcs going to a sub amp down the power side, but never run rcas used for full range down the same side as power wires. I just didn't feel like joining that discussion before. I'm going to get some numbers later here with an alternator and shed some light on this for some people, lucky for me we test alternators here at work.


I work in the aviation industry... specifically the Air Traffic Control Electronics (NAV, COM, SURV)... go nuts.

Vestax put it best:


> You can see two sides of this, but most that think of it as a myth, works as an installer at one point or another.
> 
> Running power wires separate from RCA's rule of thumb was introduced probably in the early ages of poorly constructed RCA's used in cars. Open up a physics book, and look up the right hand rule. This explain why many thought that heat and magnetism would be induced on wires.... disregarding the fact that one's DC and the other's AC.
> 
> So as a result.. you get people everywhere (including the MECP) telling everyone to run their power wires separate from RCA's. Then you start to ask yourself these questions...
> There is DC voltage going through my stock wires.. why aren't my RCA's picking it up?
> My car chassis completes the circuit, why aren't my RCA's picking this up either?


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## durwood

02bluesuperroo said:


> I have all my wires run together for a time in my trunk and I have no problems. In fact, I have never experienced any problems running the wires together before as long as all the wiring was of decent quality.
> 
> I would suspect the ground before anything else. I also wouldn't worry about keeping your ground wire the length it is but you might as well make it as short as possible to have it reach your intended grounding spot.


I'd usually suspect ground too, but in some cases you have to watch out for everything. Some amps don;t isolate the ground on the rca input well enough from the internal ground inside the amp. So you can ground it the best you want, but if your rcas are too close to the power wire, it will pick things up. The older or cheaper the amp, the more likey you can pick up noise easier. MOST amps nowadays you don't have to worry about it, but every nwo and then there are ones you do.


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## Abmolech

For those of you who think that normal coaxial RCA are not up to the task of noise rejection..

Have a look at your antenna cable, this goes through some of the worst areas for noise in your car. It also has to transfer MHz unmolested, rather than the easy 20 kHz maximum.

Point
Unless you have faulty RCA cable it is not the problem.

Start with some mute plugs in the power amplifiers. This will give them a unity signal (pure). Start the car turn on the power amplifiers.

Noise?

It is the power amplifiers and forward (Poor power supply, passive crossovers and/or driver voice coils inducting EMI or RF or you have shortered your speaker wires to the chassis(New reference signal).

No Noise.
Turn on your headlights and air conditioning.

Noise.
Fix the ground supplies (clean) to these units. Give your battery and ground supplies a "birthday".

If you have NO noise it is the head unit and processors or possibly ripple riding on your reference signal.

It is entirely feasible that you have MULTIPLE problems.

For ONCE in a audio car forum, can we please advice to do things properly. Your "peppered" approach is POOR advice.


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## durwood

I was an installer. Also, just because your battery is dc and your alternator has voltage regualtor, does not mean AC does not exist to a point in athe car. There are AC spikes that ride along the DC when the alternator is not full fielding. You don't get a smoother DC until higher revs. So it is possible to pick up some AC noise with poorly shielded wires.

Added: Good post/advice Ambolech.


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## durwood

thapranksta said:


> The place I grounded the wire has no paint at all. It appears to be completely metal.


This worries me however. It's probably painted you just can't tell. If you didn't scrape it then it's not bare metal.


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## Abmolech

> So it is possible to pick up some AC noise with poorly shielded wires.


They would have to be quite poor.

Do you REALLY want to know what the weak link is with RCA cables?

It is not the wire, it is the terminators. Your wire is normally good for 50-75 ohms impedance, put those terminators on the end, you lucky if there 20 ohms impedance. Use the the canare terminators (or their equivalent) these keep the centre to outside (coaxial) ratio.
These are good for 75 ohms impedance.

Try those "good" RCA or even worse twisted pair (junk) on the monitor cable. Watch your picture become unveiwable.
Yep it is transferring MHZ not kHz. Try the canare terminated or BNC (same as antenna) and .."lol and behold" ...picture perfect.


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## chad

Abmolech said:


> For those of you who think that normal coaxial RCA are not up to the task of noise rejection..
> 
> Have a look at your antenna cable, this goes through some of the worst areas for noise in your car. It also has to transfer MHz unmolested, rather than the easy 20 kHz maximum.


Not only that but it's ****ty coax and in a receive situation


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## durwood

AC ripple spikes coming of an alternator/regulator looks like it falls around 2kHz at idle. I don't have any good solid numbers but rough measurements on a scope reveal it to be somewhere around that. 

Chad's Experience when both the source and another amp/crossover both have the signal shield grounded and it's not isolated (i.e. poor amp/crossover/eq input design or bad cable design)


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## chad

Abmolech said:


> Try those "good" RCA or even worse twisted pair (junk) on the monitor cable. Watch your picture become unveiwable.
> Yep it is transferring MHZ not kHz. Try the canare terminated or BNC (same as antenna) and .."lol and behold" ...picture perfect.


Yup!

BUT I must add that cable impedance does not make much of a difference at AF frequencies, hell, cable impedance makes little difference in RF if it's a receive component. But try shoving RF down a 75 ohm cable when the transmitter wants 50 ohm  

I still sing the song of coax cable with the highest percentage of shield you can get. I just don't worry about impedance.


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## chad

durwood said:


> Chad's Experience when both the source and another amp/crossover both have the signal shield grounded and it's not isolated (i.e. poor amp/crossover/eq input design or bad cable design)


Fixed that problem  It was due to isolation, both units grounded works great with the exception of the ****ty interconnect I'm STILL running that's picking up induced blower noise in very, very, tiny amounts. (lines go right under the blower area)

I have the service manual for the deck and I'm going balanced soon 

Chad


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## durwood

I only posted that to show possible causes. I thought it was a good thread/example.  Glad it's all worked out, but you are picking up other noises with "****ty cables" even though it's not alternator whine.


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## kimokalihi

When I had the alternator whine, I had the power coming down the middle of the car and the RCAs down the passenger side and they both met up under the seat where the amp is. The RCA was way too long for this and was in a coil under the seat so it was right on top of the power cable. 

I tightened the coil and moved it as far away from the power cable as I could while still keeping it under the seat and it went right away. That was with cheap American Accessories RCAs. Now I have the knukonceptz crystal cable and there's no whine. Triple shielded so it better not whine.


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## chad

durwood said:


> I only posted that to show possible causes. I thought it was a good thread/example.  Glad it's all worked out, but you are picking up other noises with "****ty cables" even though it's not alternator whine.


Oh yeah, a blower makes hella RFI, before relocation I had fuel pump noise too. My fuel pump ain't right. It's sooo electrically noisy that if I drive next to a semi it shuts down the receive on their CB, and at 2M (144-148MHZ) I have to use tone squelching. Antenna cable is Davis RF buryflex (good ****) with a 1' whip of RG174 100% shield to a 1/4 wave "pigtail" and another 2' whip up front.

If someone drives my car I can hear it coming down the road to my house on many of the HF bands and in my driveway it's 20dB over S9 OUTSIDE the antenna coverage pattern


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## durwood

kimokalihi said:


> When I had the alternator whine, I had the power coming down the middle of the car and the RCAs down the passenger side and they both met up under the seat where the amp is. The RCA was way too long for this and was in a coil under the seat so it was right on top of the power cable.
> 
> I tightened the coil and moved it as far away from the power cable as I could while still keeping it under the seat and it went right away. That was with cheap American Accessories RCAs. Now I have the knukonceptz crystal cable and there's no whine. Triple shielded so it better not whine.


It must have been in your head. According to some RCA cable are incapable of picking up noise. 

I've had to move wires around to get rid of minor noise myself. Not all of us unfortunately have imaculately perfect installs especially when things are under constant change.



chad said:


> Oh yeah, a blower makes hella RFI, before relocation I had fuel pump noise too. My fuel pump ain't right. It's sooo electrically noisy that if I drive next to a semi it shuts down the receive on their CB, and at 2M (144-148MHZ) I have to use tone squelching. Antenna cable is Davis RF buryflex (good ****) with a 1' whip of RG174 100% shield to a 1/4 wave "pigtail" and another 2' whip up front.
> 
> If someone drives my car I can hear it coming down the road to my house on many of the HF bands and in my driveway it's 20dB over S9 OUTSIDE the antenna coverage pattern


Sometimes you really lose me. LOL


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## chad

durwood said:


> Sometimes you really lose me. LOL


Cliff notes  

Fuel pump is so electrically noisy that it emits enough RFI that I can hear it on a ham radio coming from 1/2 mile away. Even in the driveway and not in the antenna coverage pattern (don't want it radiating down for obvious reasons (makes you have naked babies)) it would still pin the RF meter on my radio.

Chad


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## durwood

LOL Ya I figured it was something like that but your last two sentences were overloading me with RF lingo.:blush:


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## POLKAT

I went through alot of the pain you are going through.

http://www.diymobileaudio.com/forum/showthread.php?t=9375


In the end, my problem turned out to be a combination of a bad ground and a bad amplifier. *Not* the 880prs for once lol.


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## Abmolech

I did NOT state the coaxil cable is impervious to EMI and RF. I stated that it was very good at rejecting noise. The terminators are the main weakness, however they are not sufficiently poor to cause problems.(Except for grounding the "hot" pin)

If you believe RCA cables are sooooooooo poor, why do you run to signals in parallel. IE run two cables adjacent to each other, and just as bad, run speaker cables with them, both create suitable wave forms to be transmitted via EMI. 

If your serious you start with mute plugs in the power amplifiers.



> In the end, my problem turned out to be a combination of a bad ground and a bad amplifier.


Note *multiple* causes....


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## thapranksta

durwood said:


> This worries me however. It's probably painted you just can't tell. If you didn't scrape it then it's not bare metal.


You were right. It appeared gold but after sanding, the gold rubbed off. I ended up breaking my grounding bolt after I had sanded the whole thing though (see my other thread). After finally getting the bolt out and putting a new 10mm bolt on the same ground (now sanded down), the whine is still there.  I'm lost. I guess I can search for another ground and try that or see if it is, in fact, the RCA cables. The Kicker cables look like top notch stuff but who really knows.


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## mgzzz

do you have a capacitor if not try to install one ive had similar problems in the past, but when i installed a capacitor the noise diappeared.


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## durwood

thapranksta said:


> You were right. It appeared gold but after sanding, the gold rubbed off. I ended up breaking my grounding bolt after I had sanded the whole thing though (see my other thread). After finally getting the bolt out and putting a new 10mm bolt on the same ground (now sanded down), the whine is still there.  I'm lost. I guess I can search for another ground and try that or see if it is, in fact, the RCA cables. The Kicker cables look like top notch stuff but who really knows.


I don't know how hard it is for you to move your cables to the other side of the car away from your power wire, but I would strongly recommend that, even though everyone claims it's nonsense. It won't cost you any money, only time.


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## thapranksta

It would be pretty tedious work. All my wires are tied down and rerouting would be a *****. Me being a newb, I never thought that I would have to crank up the car to check for whine. All my speaker locations were already set in stone so I just sat still and played around with my gains. I got problems with hiss too but I wanted to address the whine first (and hope that the hiss would go too).

I'll get some more RCA's from Walmart and see if the whine goes away. Hopefully, the hiss too.

My sound system sounds pretty disappointing now even without all the obnoxious sounds.  I don't want to rant so I'll end my post with that.


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## Abmolech

Do you know how to make mute plugs?


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## thapranksta

^No. Is it easy and why?


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## Abmolech

Yes it is easy.

Buy the least expensive male RCA terminators possible.

Unscrew the plastic cover. There are two soldering points on the RCA terminals one for the centre, the other for the ground. Simply cut a 5 cm length of wire, strip the ends and solder the ends to each (ground and centre , so you short circuit the RCA)

When placed in the input of your power amplifier they will provide a "pure, noiseless" unity signal. (they can also be used to fault-find processors)

Place them in all the inputs.

Start your car, turn on the power amplifiers (remote turn on on the head unit is fine)

see my first post.



> Point
> Unless you have faulty RCA cable it is not the problem.
> 
> Start with some mute plugs in the power amplifiers. This will give them a unity signal (pure). Start the car turn on the power amplifiers.
> 
> Noise?
> 
> It is the power amplifiers and forward (Poor power supply, passive crossovers and/or driver voice coils inducting EMI or RF or you have shortered your speaker wires to the chassis(New reference signal).
> 
> No Noise.
> Turn on your headlights and air conditioning.
> 
> Noise.
> Fix the ground supplies (clean) to these units. Give your battery and ground supplies a "birthday".
> 
> If you have NO noise it is the head unit and processors or possibly ripple riding on your reference signal.
> 
> It is entirely feasible that you have MULTIPLE problems.
> 
> For ONCE in a audio car forum, can we please advice to do things properly. Your "peppered" approach is POOR advice.


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## thapranksta

I have no experience with soldering. Can i do the same by crimping the centre and ground of some old rca cables that i have laying around the house?


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## Abmolech

Absolutely, just make sure they are short circuited.

Ground loops.

Every car audio system has them, as soon as you use a ground for a power supply, and then a ground reference (RCA shield) you have created a "ground loop".

The ground loop is NOT the problem.

The problem is where you power amplifier derives its ground supply from.

Resistance = resist. Like me energy is lazy, and if it can find an easier route, it will do so. In this case you have a nice clean RCA ground (low resistance) and POSSIBLY a poor ground supply (higher resistance). Energy, being lazy, will take the nice clean RCA ground until both grounds are equalised (potential difference). So how is this a problem?

The reason for the RCA ground is to supply the power amplifier with a reference signal. If you have another signal "riding" on that signal it will amplify that as well.
In this case that signal COULD be the power supply to the power amplifier.(IE the revolution noise of your alternator field windings)


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## chad

^^^^^^^^

Well done!


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## thapranksta

I haven't gotten around to making the mute plugs but I did find and try another pre-drilled factory grounding spot. Whine is still there so I doubt that it is the location of the amp ground. Can whine be caused by having your gains turned up too high?

For some reason, I suspect my Kenwood DDX-6019 headunit. The whine starts as a big burst. Then it mellows down to a low but noticable whine. As the rpm climbs, so does the whine.

Any more ideas before I try the mute plugs?


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## Vestax

thapranksta said:


> I haven't gotten around to making the mute plugs but I did find and try another pre-drilled factory grounding spot. Whine is still there so I doubt that it is the location of the amp ground. Can whine be caused by having your gains turned up too high?
> 
> For some reason, I suspect my Kenwood DDX-6019 headunit. The whine starts as a big burst. Then it mellows down to a low but noticable whine. As the rpm climbs, so does the whine.
> 
> Any more ideas before I try the mute plugs?


Anytime you have different level of voltages for each component, it could cause problems. This is why the guys are telling you to reground. 

If you want a quick band aid, try this.

Take several small pieces of 16-18awg wires and ground the outer shield of your RCA's. See if the noise goes away.


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## thapranksta

I'm in the process of buying another HU and I got a new component set coming in so my system is completely undone right now and I'm riding with the stock radio and just rear speakers. But I will ask these questions so that I know what to try when I can get my new gear.


Would it be worth it to ground the HU and the amp in the same place? My HU was grounded to the stock radio wiring at first.


Do you have any pictures of what you are referring to when you say "take several small pieces of 16-18awg wires and ground the outer shield of your RCA's"?



Thanks for the advice man and is that Balrog from Street Fighter in your avatar?


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## Vestax

thapranksta said:


> I'm in the process of buying another HU and I got a new component set coming in so my system is completely undone right now and I'm riding with the stock radio and just rear speakers. But I will ask these questions so that I know what to try when I can get my new gear.
> 
> 
> Would it be worth it to ground the HU and the amp in the same place? My HU was grounded to the stock radio wiring at first.
> 
> 
> Do you have any pictures of what you are referring to when you say "take several small pieces of 16-18awg wires and ground the outer shield of your RCA's"?
> 
> 
> 
> Thanks for the advice man and is that Balrog from Street Fighter in your avatar?



I don't have pictures, but it's really simple, by looking at your RCA's aka coaxial cables... take a piece of wire and wrap the outer metal piece (make sure it doesn't touch the centerpin), then hook it up to ground or your head unit's chassis (since you're driving a toyota, you may have iso-mounted your deck, which is also connected to chassis). Do it for each RCA's. This method, which I learn like 6 years ago (also posted on ECA, where people thought I was crazy), works nearly 60% of the time.

Yes, that is Balrog from SF2 Hyper.  I used to compete so uh... anybody wants some butt whoopin'.. please bring it on.


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## Abmolech

> Would it be worth it to ground the HU and the amp in the same place? My HU was grounded to the stock radio wiring at first.


It is unlikely to solve the noise problem, but it is "good practise". (It can "save" your head unit, if a large ground current draw, decides to route through it. IE ground strap to engine failure)

The advantage of mute plugs, is you can start to eliminate possible noise cause. Otherwise you can just keep going around in circles.


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## thapranksta

^I still plan on trying the mute plugs when I can. Just trying to get as much advice as possible before my new gear comes in and I can try to tackle the noise issue.


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## mopower

I switched amps to my front stage and now have alt whine...have done the usual diagnosis and it seems to be coming from the amp. Arc Audio XXK 4150...any thoughts on where to go from here? 
cheers


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## Abmolech

mute plugs on the power amplifier.


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