Power wire causing amplifier output signal to distort?

[Elmadus]

Hi!
I’m having an headache with my cars sound system. It seems that no matter what parts i use, my amps output signal gets little distortion from somewhere.

So to open this up a little, here’s what i’m using:

HU: Kenwood KMM-BT304
Fronts: Skar Audio SK65C
Rears: Skar Audio SK65
4ch Amp: Rodek R4100n
Sub Amp: Alpine PDX-1.1000
Sub: Alpine Type-R SWR 1542D

The two amps are positioned under the front seats (Alpine under driver and Rodek under passenger) and the speakers are installed on the original speakers holes to keep the look of the car stock.

With this setup i’m getting small amounts of distortion from my speakers. This distortion appears on all volumes and it’s more and less present with different songs. It’s more noticable when sharper instrument’s are being played like piano or guitars.

This distortion doesn’t come out of the speaker outputs of the head unit, but putting sound through the amp makes it distorted, which could mean that the amp is the problem.

But before this setup i had a Skar audio RP-75.4ab amp with the same speakers and HU. And the same distortion existed with that amp aswell. Tried changing it to the current Rodek but the problem didn’t go away.

I’ve also tried a different head unit, but with the same result. I even tested it with my phone using an aux to RCA adapter to rule out the RCA cable. No luck with it either.

Trying different speakers wouldn’t even help it, same story with other kinds of speakers i tried on it.

I also checked all the connections that they’re properly attatched, grounding is good and so forth.

So the only possible thing that i think could affect the output is the power wire going to the amp? Or could something else interfere the signal that comes out of the amp?

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[YourNameHere 10+ year member]

learn how to properly tune a stereo and i bet your problem will disappear

 

[yamomluvsme]

Check your crossovers. Make sure they set properly

 

[Elmadus]

Check your crossovers. Make sure they set properly

I’ve set my crossovers on the head unit for the speakers with a high-pass at 70hz, shouldn’t that be enough or should i put it up even higher?

And also i’ve put the crossovers on the amp at full so they don’t interfere with the HU:s crossover settings

 

[Elmadus]

learn how to properly tune a stereo and i bet your problem will disappear

The distortion doesn’t change no matter how the settings on the HU or the amp are set, different gain positions won’t change it either

 

[YourNameHere 10+ year member]

what is the source your playing from?....bluetooth streaming, CD, thumb drive, Spotify, XM, Tidal, etc. etc.???? could be your source/recording

 

[Elmadus]

what is the source your playing from?....bluetooth streaming, CD, thumb drive, Spotify, XM, Tidal, etc. etc.???? could be your source/recording

I use an USB to my iPhone to play from Spotify. The distortion also appears on aux and bluetooth.

 

[yamomluvsme]

Sounds like a bad set of outputs on the CD player

 

[Elmadus]

Sounds like a bad set of outputs on the CD player

I thought of the same, and sent my HU for repairs. Turned out that the HU was just fine.

As i also mentioned, i tried to play some music with a phone straight through the amp using an aux to RCA adapter. The distortion was still there.

 

[yamomluvsme]

Only thing I can see is a bad ground or noise from the rcas

 

[BCotrell]

is Your power wires run separately than yours speaker wire and or rcas? If they’re all run down the same part of the vehicle that could be a problem.

 

[Elmadus]

is Your power wires run separately than yours speaker wire and or rcas? If they’re all run down the same part of the vehicle that could be a problem.

They all run from different locations. Power wire goes under the right door scuff, speaker wires through the left scuff and RCA goes from the middle between the seats.

 

[YourNameHere 10+ year member]

maybe you just got that golden ear and can hear distortion at .05 or lower.....can you hear others peoples thoughts inside their head?

 

[Jeffdachef 5,000+ posts]

could be a tear in the speaker wiring and its grounding out slightly somewhere. Could also be RCAs bad. You already eliminated the amp and head unit out of the equation. There's only a few left. Also did you install the RCA on the opposite side of the power wire or the same side?

 

[Elmadus]

maybe you just got that golden ear and can hear distortion at .05 or lower.....can you hear others peoples thoughts inside their head?

Lol, i’d say the difference is noticable when compared to the speaker output of the HU itself, which doesn’t distort it. I can post an example if it’s noticable on camera.