Theoretically couldn't you create a "shield" similar to shielded cables by a grounded foil sheet under the amp rack?

 

Thank you, sir. I have no knowledge how to do that. Do you mind to tell me how to do that please?

 

I don't know if it's a special material or anything, hopefully someone else can chime in, but the metal shielding of the cable is grounded on either end of the rca

 

Here ya go --

Amazon.com: ATMOSURE Faraday Fabric (44"L x 36"W) + Faraday Tape (51"L x 1"W) — DIY Faraday Bags for Home — DIY Military Grade Faraday Cage for EMP Protection & EMF Protection : Industrial & Scientific

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And its big enough where you might even have enough to make a hat for yourself just in case the hiss is only in your head !!! 😂 JK

 

Awesome, I was just about to ask the same question, ordering some of that now!

 

I had an issue similar to this in my bmw as the primary battery sat right under the false floor where the amps were mounted. I used a 2 farad stiffening capacitor and all noise went away.

 

Thank you, sir. That was on one of my list too if I didn't find out today what cause this problem. That will be my next step. As you can see from my first pic that next to the battery are one Brax stiffening cap and one Helix cap, 1 farad each going to each of sub amps but nothing to hi, mid, midbass amps.

 

A metal plate with a ground wire should work just as well. That type of "faraday material" is mostly for convenience/portability. If you're trying to shield a somewhat stationary object, sheet metal works just as well... Just make sure that it won't come into contact with your battery terminals. You may also want to check that material for conductivity if you're planning on draping it over your battery or something like that.

If that material doesn't work try getting some 12-16 gauge sheet metal to put under the amp. If it doesn't help, run a ground wire to it. If that clears it up, you could route a recess in the bottom of your amp rack to mount it permanently then cover it with a thin sheet of abs so there isn't a bare steel plate right above your battery.

 

Thank you, sir.

 

I just thought he could first try placing the fabric folded underneath the DSP and amp before trying anything that needed more fabrication...for $20 its a quick and EASY test.

 

I just thought he could try placing the fabric folded underneath the DSP first and amp...for $20 its a quick and EASY test.

Thank you, sir. Will do.

 

Amps and dsps are already shielded. Chassis are grounded.

 

I'm more concerned about all the wiring that has to run near and over the hybrid power wires and motor in my car. Maybe this will not do anything, but its worth $20 to put it in because I will not be able to easily get to it later.

 

"But batteries can't create noise !!!" Where are those deniers at?

Nick at Vanguard/Resonix used some Resonix Barrier to solve the same issue. There's a thread around here somewhere...

2019 Genesis G70 - High-End Sound Quality - Accuton...

Here it is, one of the latest and greatest high-end car audio installs. This time, in a 2019 Genesis G70. Let me get this out of the way right now.. this car is awesome, and the Kia/Hyundai brands really stepped their game up over the past few years. Seriously. Moving on to what we all want to...

www.diymobileaudio.com

 

I wonder if there's anything to the fact that all three times this issue has come up in the past year, it's been at AF product...

 

It is not new to AF. I had Brax 2400 with terrible noise when I had any other amp in a car. I had to modify Brax to fix it.

 

Try installing them in my car and see if the noise goes away. If it does, problem solved.

 

Good find on the RFI from the battery as it could be the cause. You can try putting a metal reflective shield between the battery and equipment like lead sheet, cooper, aluminum, usually the more conductive the metal the better job it does at reflecting EMF/RFI. Just be sure you insulate it so it doesn't short anything out.

Additionally, you can make a shield out of PVC, wood, etc and cover both top and bottom with "faraday tape" you can find on amazon. (sometimes I would even disassemble the equipment and cover the entire inside with a layer of faraday tape and then a layer of regular clear tape as an insulator)

A stiffening capacitor could work as capacitors are filters as well, potentially normalizing the current on the electrical and lower RFI.

 

Faraday fabric doesn’t work. Spent 4 hrs trying to fix the problem but no luck. Some of the noise go away after changed tweeter rca but much more quieter when the amp rack lifted.
Also lifted up both amp and dsp about 1.5” from the amp rack but nothing change.

Since faraday fabric doesn’t work. Do you guys think a sheet of metal might work?

Thank you,

 

Faraday fabric doesn’t work. Spent 4 hrs trying to fix the problem but no luck. Some of the noise go away after changed tweeter rca but much more quieter when the amp rack lifted.
Also lifted up both amp and dsp about 1.5” from the amp rack but nothing change.

Since faraday fabric doesn’t work. Do you guys think a sheet of metal might work?

Thank you,

A dang, but considering how strong that interference is, I can understand why didn't work.

A sheet of metal could work but try that as a last resort. Have you tried disconnecting everything else from the amplifier (as its the device directly connected to your tweeters) except the power and tweeters and checking if the noise goes away?

On that note, a test I usually do as well is using an extra piece of wire and shorting (connecting) the outer RCA shield of the tweeter driving amp and dsp through different combinations like:
-amp RCA out to amp RCA in
-DSP RCA out to DSP RCA in
-DSP RCA in to amp RCA in
so on and so forth..

 

T

Good find on the RFI from the battery as it could be the cause. You can try putting a metal reflective shield between the battery and equipment like lead sheet, cooper, aluminum, usually the more conductive the metal the better job it does at reflecting EMF/RFI. Just be sure you insulate it so it doesn't short anything out.

Additionally, you can make a shield out of PVC, wood, etc and cover both top and bottom with "faraday tape" you can find on amazon. (sometimes I would even disassemble the equipment and cover the entire inside with a layer of faraday tape and then a layer of regular clear tape as an insulator)

A stiffening capacitor could work as capacitors are filters as well, potentially normalizing the current on the electrical and lower RFI.

Thank you, sir.

 

After I think it over when I disconnected the tweeter rca from the amp then no more noise so is that mean the problem must be from DSP? I am just confused now.

Yes, I have 12v power supply so I can try to hook that up to the amp and will bump up the voltage to 14V and will see what would happen.

 

The noise might be present on the other channels, but the tweeters are typically the most efficient driver in the system so it will be more apparent with them.

To properly troubleshoot you need to do a very methodical job from source to receiver, one component at a time. GL

 

The noise might be present on the other channels, but the tweeters are typically the most efficient driver in the system so it will be more apparent with them.

To properly troubleshoot you need to do a very methodical job from source to receiver, one component at a time. GL

Thank you, sir.

 

The noise might be present on the other channels, but the tweeters are typically the most efficient driver in the system so it will be more apparent with them.

To properly troubleshoot you need to do a very methodical job from source to receiver, one component at a time. GL

I have a spare set of old tweeters for testing stuff like this, for that reason.

 

Not necessarily - it means that the hiss is being injected by the RCA cable but not necessarily from the DSP.

Reconnect the RCA causing the hiss and then disconnect the other end from the DSP - if the hiss goes away then the DSP is part of the problem. If the hiss persists while disconnected from the DSP then the RCA cable is picking up the interference and should be replaced or rerouted.

Sent from my SM-G965U using Tapatalk

Thank you, sir.
“disconnect other end from DSP”
Do you mean to disconnect the rec end that attached to DSP where the signal go into the amp? On the other word is Analog output from DSP. And leave other end connect it to amp analog input.
I think I did that yesterday already and the hiss disappeared after disconnected rca end at the DSP but will make sure to try it again today.

 

Once you have identified a piece of the signal chain that can get rid of the problem you have a course of action.

Disconnecting the RCA cable at the amp made the hiss go away and plugging it back on the hiss returns.

Then you go to the other end of the same RCA and unplug: Hiss goes away then the RCA is only carrying the hiss not the source.

IF the hiss persists with the signal source disconnected then the RCA cable is the source.

Assuming the hiss goes away then you start disconnecting one cable at a time from the DSP till the hiss goes away again... if you disconnect everything and the hiss persists you pull power, etc till it goes away.

Sent from my SM-G965U using Tapatalk

Thank you, sir. Will give it a try first thing in the morning.

 

It is much better today by moving RCA around. When I was trying to use a right angle rca and it got worst, don't know why and seem it doesn't make sense to me. Also got worst when rca got close or toughed the amp so when I put 1/2" birch wood between the amp and rca cable some of the noise go away but not sure because of the distance between rca and amp or the wood block that hiss.

Thank you everyone here for trying to help me out.

 

Not much shielding on those RCAs or are you able to run balanced on that equipment?

 

No, not much at all. No balance, I hope they offer that also. I love the sound of those cable. I will call them tomorrow to ask them if they recommend any type of shield over their cable.
Here is the cable. Customize - Silver Streak

 

jesus, this is more my speed

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Despite the introduction of more advanced audio and video signal cables, such as HDMI® and Toslink, most audio and a large number of video connections still use the common RCA connector.This is a

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Not much shielding on those RCAs

GOOD catch...wasn't obvious int he first pic OP posted.

That said, save some of your hard earned monies and get yourself some of these quality fully shielded coax RCA cables made by Esoteric. They are closeout prices on Ebay but Esoteric made NICE cables...promise you wont hear a difference between them and those $PENDY ones your running ... except the hiss will be gone !!!

Esoteric Audio USA A3 Series RCA Audio Cable 24K gold plated contacts | eBay

Patented split banana center pin. Poly Flex Outer Jacket. Phase Flow Teflon Dielectric. Hyper Twist. Precision Negative Collar. Sure Grip Connector.

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You’re looking for this…

https://content.kemet.com/datasheets/KEM_FS8004_NSS.pdf

 

No, he is looking for shielded RCA cables....

 

And for quality cables that reduce rfi emi that won’t break the bank I would look at SKW rca cables, but specifically the ones that feature a copper outer shell, opposed to aluminum in their lower level offerings.

 

Instead of conjecture, get one of these and confirm the location of the EMI. I have one and it was very eye opening where the EMI was coming from.

ERICKHILL EMF Meter,3-in-1Rechargeable Digital Electromagnetic Field Radiation Detector for EF RF MF,5G Cell Tower, WiFi Signal Detector, for Home&Office EMF Inspections, and Ghost Hunting: Amazon.com: Industrial & Scientific

 

Instead of conjecture, get one of these and confirm the location of the EMI. I have one and it was very eye opening where the EMI was coming from.

ERICKHILL EMF Meter,3-in-1Rechargeable Digital Electromagnetic Field Radiation Detector for EF RF MF,5G Cell Tower, WiFi Signal Detector, for Home&Office EMF Inspections, and Ghost Hunting: Amazon.com: Industrial & Scientific

Thank you. Yes, I got the same one. The link below I was checking Magnetic fields.