Static from factory HU over volume 17 (out of 40)

[rostam]

Hey,

I was inspired me to build my own sound system in my 2013 Accord Sport based on the forums here. I'm having major problems with the sound quality. Can anyone assist? Here's what I did.

I started with components up front. Tested it out and it worked great. Then I installed an amp and a new battery. I mounted the amp under the rear deck. I cut the outputs from the factory HU to the front speakers from behind the HU and spliced them onto a braided RCA and input into the amp (Alpine PDR-F50) as speaker level input. I spliced into the ACC and sent that as the remote to the amp. Then I ran the speaker wire from the amp to the original front speaker cables behind the HU.

I fired up the amp and sounds like ****, I hear a terrible hiss and crackling when I turn the volume up. So I disconnected the amp and front speakers. That leaves me with the factory HU and rear speakers.

Wierd thing is that I can still hear the crackling and static above volume 17-20 (out of 40) now. It is with the radio and bluetooth from the phone. It is worse with songs rather than talk radio. The amp and the front speakers are out of the equation. I made sure there were no loose connections behind the HU. No wonder my system sounds terrible. The input is dirty.

Have you had this experience? What's going on? What can I do to troubleshoot or remedy the problem?

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[LosIsATool 5,000+ posts]

Gains or bad ground. Either LOC or amp

 

[rostam]

I took the amp out of the equation. I disconnected it from the battery. The stock HU is connected to the rear speakers and I still hear static on music tracks over volume 17.

 

[Boomin_tahoe 5,000+ posts]

@Jeffdacheff Preach your stock HU and related problems!!

Get a better HU, and your problems will go away. You got a 4 ch amp so once that set in place should be all better.

 

[rostam]

I'm going for the stock look. With the newer cars it's really difficult to replace the HU, since it has bluetooth, display, steering wheel controls, etc built in.

 

[rostam]

@LosIsATool Do you mean that the ground to the factory HU may have been damaged by pulling on the harness?

 

[Boomin_tahoe 5,000+ posts]

All that stuff can be factored in with the new HU.

Don't know if you know or not but a lot of HU's have the built in bluetooth, pandora, aux input, etc....many many features you can shake a stick at.

 

[ashren315]

Wait. You are using high level output off the radio to the low level input on the amp simply by splicing into the wires and connecting RCA ends to it?

 

[rostam]

The amp has high level inputs, up to 4v (Alpine PDF-F50). But I have removed the amp and the front speakers from the circuit. Wierd thing is that I'm getting noise on the rear speakers connected directly to the stock factory HU.

 

[ashren315]

Oh. I c what you are saying.

Do you still by chance have the RCA ends connected to your speaker wires? You could have some touching wires possibly.

 

[Jeffdachef 5,000+ posts]

Unless its through a DSP or a quality LOC like a JL cleansweep, i would never use high level inputs. Every audiocontrol LOC, or hi level install I've seen always has major issues either with noise or horrible sound quality.

There's steering wheel adapters, bluetooth touch screen head units. The only thing thats not built in is if your head unit also controls the AC and heater. Otherwise, theres no reason to keep a sh*tty stock head unit.

 

[rostam]

I'll be sure to include a head unit in phase II of the build. For now, I would just like to get the stock rears working with the stock HU. @ashren315, no touching wires, made sure. They are heat shrink wrapped behind the unit and isolated physically at the other end. Maybe I got a little aggressive due to the limited slack and mangled the stock ground?

 

[ashren315]

I would think if it was a ground or power wire you would blow a fuse or the unit would turn off and back on constantly. It really sounds like a + and - speaker output wire is touching or a + speaker wire is grounding out somewhere but if you are sure there is no way that is happening, I'm at a loss without seeing and hearing it for myself.

 

[rostam]

@ashren315 Thanks for the feedback. That makes alot of sense. I think you're on to something. I will check the pull the HU and check/rewire the wiring. I'll update soon

 

[rostam]

I did two things.

First I disconnected my amp completely and only ran the rears off the factory head unit. Fading completely to the rear, no problems. When fading to the middle, i get static/crackling when increasing the volume past 17ish. I suspected a short in the front output somewhere between the HU and the end of the RCA cables I had spliced into the Front Factory speaker outputs. I pulled the HU and the splice looked good, so that means that the shielded RCA cables cannot handle the high voltage from the speaker level outputs. So I got rid of the RCA cable and extended the front outputs with 16 awg wire to the trunk.

Second, I got an LOC and input the speaker wire into the LOC and output into the amp and voila. My system is killer. Thanks for your help.