# Constant high-pitched noise



## Comp-U-Geek (Jan 23, 2009)

OK, I've tried the usual tricks on this problem and it has not gotten any better. It is a new install on a 2012 Mustang. JVC KW-XR810 HU, ID Q450 for mids/tweets, PG Xenon 200.2 for door midbass, Kenwood X1R for sub, RF RCA cables. All 3 amps grounded to same grounding point under a rear seat mount bolt. Sanded down to bare metal for the connection.

Symptom is a very high pitched constant noise. I'd guess its in the 15hkz range since I've had 1 person get in the car and told me they couldn't hear it at all. To everyone else it is rather loud. The sound does not ever fluctuate, not with RPM, not with moving the cables around, nothing.

I've tried moving cables around, tried grounding the amps to another bolt under the rear seat and the same noise persisted.

Looking for any ideas you may have. I've never encountered a noise problem like this before and searching didn't turn up much either.


----------



## gozaine (Jan 4, 2012)

Comp-U-Geek said:


> OK, I've tried the usual tricks on this problem and it has not gotten any better. It is a new install on a 2012 Mustang. JVC KW-XR810 HU, ID Q450 for mids/tweets, PG Xenon 200.2 for door midbass, Kenwood X1R for sub, RF RCA cables. All 3 amps grounded to same grounding point under a rear seat mount bolt. Sanded down to bare metal for the connection.
> 
> Symptom is a very high pitched constant noise. I'd guess its in the 15hkz range since I've had 1 person get in the car and told me they couldn't hear it at all. To everyone else it is rather loud. The sound does not ever fluctuate, not with RPM, not with moving the cables around, nothing.
> 
> ...


REVIEWS CABLE RCA


----------



## Comp-U-Geek (Jan 23, 2009)

gozaine said:


> REVIEWS CABLE RCA


Um..... Where is the rest of the sentence?


----------



## gozaine (Jan 4, 2012)

Comp-U-Geek said:


> Um..... Where is the rest of the sentence?


check the cables rca
interference noises are produced by being very close to other cables, the cable must be coated


----------



## gozaine (Jan 4, 2012)

you read
How to Eliminate Engine Noise - Knowledge Base


----------



## bobduch (Jul 22, 2005)

Do not use a seat bolt. They are zinc plated and that can be a problem. Yes for real. I would not have believed it either but it happened to me. Lycan gave me the explanation why which was a bit over my head.


----------



## Comp-U-Geek (Jan 23, 2009)

gozaine said:


> you read
> How to Eliminate Engine Noise - Knowledge Base


Yeah, I've seen that before, but that is about the alt noise that changes with RPM. The noise I have is constant. It never changes in volume or tone.



bobduch said:


> Do not use a seat bolt. They are zinc plated and that can be a problem. Yes for real. I would not have believed it either but it happened to me. Lycan gave me the explanation why which was a bit over my head.


I'm not sure if I can avoid that on this car if that is the case. All the bolts under the back seat and the seat belt bolts are of the same size painted black. I had zinc plated bolts before on my Subarus, but the ones on the Ford are black paint....... Not sure what metal is under the paint. Right now, though, I have the ground eyelet between the frame and the bracket for the rear seat. Not sure if it is even contacting the bolt right now. I have also tried it on top of the bracket in direct contact with the bolt and the same noise was observed.

I tried finding another bolt in that area with no success. Just some small screws that may or may not even contact the frame.


----------



## The Baron Groog (Mar 15, 2010)

Earth straight to the chasis, seat bolts are painted before assembley=poor contact. Find a nice flat area, check nothing important underneath and sand it back to bare metal and drill through then bolt down.

Also does the sound come from all speakers or just one pairch? If just one pair/ch then check you don't have the speaker cable pinched anywhere-spent a few hours trouble shooting a similar noise and found the customer had accidentally bolted his tweeter wire under his seat belt bolt-removed the wire and cured the issue.


----------



## Comp-U-Geek (Jan 23, 2009)

The Baron Groog said:


> Earth straight to the chasis, seat bolts are painted before assembley=poor contact. Find a nice flat area, check nothing important underneath and sand it back to bare metal and drill through then bolt down.
> 
> Also does the sound come from all speakers or just one pairch? If just one pair/ch then check you don't have the speaker cable pinched anywhere-spent a few hours trouble shooting a similar noise and found the customer had accidentally bolted his tweeter wire under his seat belt bolt-removed the wire and cured the issue.


Right now the eyelet for the ground cable is sandwiched between the rear seat bracket and the chassis (both sanded to bare metal). I doubt it is even touching the painted bolt. How much (if any) does the bolt itself matter if it is not being used as a contact surface?

I have one set of RCAs run to the ID Q450.4 (2ch input on the amp switch) for mids and tweets. The noise comes only through the tweeters (both equally as loud) as the noise is far too high pitched for my 4" mids to reproduce even if they are seeing the same interference/input/noise/whatever.


----------



## The Baron Groog (Mar 15, 2010)

Still not an ideal location, personally I'd try re mounting the earth.

Try running your mids on the tweeter channel-if they're 4" they'll play high enough and would allow you to rule out the tweeter wiring


Sent from my Motorola DynaTAC using Tapatalk


----------



## Sine Swept (Sep 3, 2010)

Why not skip your chassis altogether and run a dedicated 1/0 or what have you all the way to the battery - wire is cheap in comparison to all the gear cost. Then you just need a distroblock to terminate all your ground wires.

BTW no has mentioned turning the gain down a bit - have you tried?

Sounds like noise floor.


----------



## Comp-U-Geek (Jan 23, 2009)

Update on this thread - everything has changed and changed again. :laugh:

Changed out the amp for a Kenwood X4R and the noise went away. This amp has a built-in DSP plus the class D filtering so that may have processed it out.

Recently I upgraded the headunit and while on the Kenwood X4R amp, the noise was still gone.

Changed the setup again to have a PPI X3 crossover before an old Zeff based CV EXL amp and the noise is back. Same frequency as before but maybe a little quieter than before. The noise only comes through the tweets, no mids I've played with in this car have produced the noise running off the same RCA cable and amp as the tweets.

Ground is bolted directly to chassis sanded to bare metal. That ground runs to a distro block that all the amps connect to. Only thing I can think of is to try running a ground wire from the amp distro block to the H/U and bybassing the ground in the factory harness. This sound like a possible solution or is there still something I'm missing here?


----------



## Elektra (Feb 4, 2013)

Comp-U-Geek said:


> Update on this thread - everything has changed and changed again. :laugh:
> 
> Changed out the amp for a Kenwood X4R and the noise went away. This amp has a built-in DSP plus the class D filtering so that may have processed it out.
> 
> ...


I know this is a old thread so I am reviving it as I just installed a new system and I get that same annoying high pitched sound which is constant in volume - sounds like high pitch ringing with like a computer noise to it.

I wonder if a good cap can solve this issue? All my stuff is BNIB so it not old stuff using the highest grade rca and speaker cable using 100% copper power and earth cable which is 2awg double run (1 power 1 earth per channel - dual mono amps) 

I believe a proper cap can filter out noise... I have a Brax IPC 2 farad cap at home - what do you guys think? 

Has anyone tried this?


----------



## Comp-U-Geek (Jan 23, 2009)

Not sure what that would do.... I have since installed a system in another S197 mustang for a friend and ran into the same noise even though pretty much every component in his car is different. I got out the RTA and found this noise to be around 17k. His amps are even grounded to a different place than mine. On his system, I ran a ground wire from the h/u back to the ground block for the amps to eliminate that as an issue. Same constant noise at the same frequency. When I re-wired my entire system, I added a Helix DSP and the noise went away on mine. Its coming through the RCAs, just not sure how, unless there is just so much electronic crap in these cars its causing too much interference.


----------



## gstokes (Apr 20, 2014)

You can't ground through paint, no matter what color 

Direct to the chassis VIA an unpainted steel bolt or direct to the negative terminal on battery..

Be sure there is a good Chassis > Battery ground..

Moving around the wrong Interconnect or using an Interconnect with poor shielding does nothing, what Interconnects are you using ?


----------



## MikeS (May 23, 2015)

Comp-U-Geek said:


> Not sure what that would do.... I have since installed a system in another S197 mustang for a friend and ran into the same noise even though pretty much every component in his car is different. I got out the RTA and found this noise to be around 17k. His amps are even grounded to a different place than mine. On his system, I ran a ground wire from the h/u back to the ground block for the amps to eliminate that as an issue. Same constant noise at the same frequency. When I re-wired my entire system, I added a Helix DSP and the noise went away on mine. Its coming through the RCAs, just not sure how, unless there is just so much electronic crap in these cars its causing too much interference.


Helix dsp has ground lift switch and it's by default on position where input/output ground is galvanically decoupled so it cuts a possible ground loop/source of noise there.


----------



## Comp-U-Geek (Jan 23, 2009)

gstokes said:


> You can't ground through paint, no matter what color
> 
> Direct to the chassis VIA an unpainted steel bolt or direct to the negative terminal on battery..
> 
> ...


Right, both cars are sanded to bare metal for the ground point..... they are just grounded at different points. Putting the multimeter leads on the ground lug on an amp and touching the other to the bare metal of the chassis where the paint had been sanded off read 0.00 to 0.01 ohm. Now, the battery side, I have not done anything with, so its possible the factory grounds are just terrible at the battery side.

My car used to have Rockford RCAs (and I ran a Stinger brand as a temp to see if that changed anything, but it did not), his car has the Knu Basic RCAs, and when I re-did my car, I used the Knu Karma SS RCAs.


----------



## gstokes (Apr 20, 2014)

Comp-U-Geek said:


> Right, both cars are sanded to bare metal for the ground point..... they are just grounded at different points. Putting the multimeter leads on the ground lug on an amp and touching the other to the bare metal of the chassis where the paint had been sanded off read 0.00 to 0.01 ohm. Now, the battery side, I have not done anything with, so its possible the factory grounds are just terrible at the battery side.
> 
> My car used to have Rockford RCAs (and I ran a Stinger brand as a temp to see if that changed anything, but it did not), his car has the Knu Basic RCAs, and when I re-did my car, I used the Knu Karma SS RCAs.


Good deal, the chassis is usually connected to the engine block VIA of a way a steel or brass braided strap or cable then the engine block is connected to the battery negative VIA another cable, having a connection between the chassis and/or body direct to the battery is a good thing..
That's what the big three does, just amplifies the existing grounds and creates a low resistance path for current to follow..

I have good luck with the Stinger 4000 Series Interconnects..


----------



## Blackheart (Feb 6, 2021)

gstokes said:


> Good deal, the chassis is usually connected to the engine block VIA of a way a steel or brass braided strap or cable then the engine block is connected to the battery negative VIA another cable, having a connection between the chassis and/or body direct to the battery is a good thing..
> That's what the big three does, just amplifies the existing grounds and creates a low resistance path for current to follow..
> 
> I have good luck with the Stinger 4000 Series Interconnects..


I’m having this same issue in my 2020 bi turbo XLT Ford ranger, the DSP block could be a good idea, as when I turn the dsp position onto a different position it does change, I’m going to try a 40amp inline noise filter first but the DSP block sounds like a good 1 to try aswell, let me know if u find out what is causing it.


----------



## TTRICK (9 mo ago)

Blackheart said:


> I’m having this same issue in my 2020 bi turbo XLT Ford ranger, the DSP block could be a good idea, as when I turn the dsp position onto a different position it does change, I’m going to try a 40amp inline noise filter first but the DSP block sounds like a good 1 to try aswell, let me know if u find out what is causing it.


did you solve it please give me a solution PLEASE!


----------

