ok as you know i have a system in my truck. well i noticed my headunit volume was on 0. but my sub was going "whump whump" and it sounded like a evap leak ound comming from the sub as well. I start moving, and it gets louder as i accelerate. It sounds like its relaying noise from the motor.

I say this because when i turn the head unit off, the noise and everything goes away. and in the motor i can hear a slight vacuum leak (which i know i have one and where it is...been injured and havent been able to fix it) and it sounds like the subs are relaying that exact sound.

When i have the music up i can still hear the noise under the vocals. but when i turn it up past 40 for volume, it goes away. and will stay away until truck is restarted and then back at square 1.


All my wiring is free of chaffing, touching or anything, so how can this be happening?

 

wheres your amp grounded? usually thats a sign or a bad ground

 

or a ground loop.... example grounding the stereo to the battery and amp grounded to the frame.... the whole system should share the same ground... you can also buy noise insulators for the power to help....running the preout rca cables with the power cables is also a bad Idea because it can pick up radio noise interference ...better insulated plug wires can help too sometimes...

 

its grounded to the between the seat bracket, and the bolt that goes on it to hold seats in. i figured it wouldnt share the ground right there. and the system has been in it for 4 months and today is when it started

 

swap the head unit and i betcha it changes..some head units do that..if you wanna see if its your head unit unplug the rca's while the head unit is on and playing a song..and see if it changes..

 

while its making the noise right?

because like i said when i turn the volume over 40, it eventually goes away, and doesnt come back until i restart the truck.

Also i just came back from shopping, and i can hear my water pump whining (which is weird cuz its brand new 9K on it, wasnt a reman or used its NEW) and thats the sound its amplifying. and the "whump" it gives off sounds like an internal motor/tranny noise...sort of like an exhausted camshaft....kinda hard to explain.

 

Check all wiring in the truck. It doesn't have to be a bare wire to make that sound. If you've ran the power wire along side the RCAs, then that's the probable cause of the issue. With the power wire going to the engine bay, and having copper plug wires, you can easily pick up feed back. Also, an amplifier that has a blown channel will also make the same sounds. You can take the amp into any audio shop and flip them $10.00 and they'll bench test it for ya to see.

 

Or he could just turn it on without starting the engine to rule out a bad channel on the amp?...If it only does it with the engine running its radio interference....a noise filter on the head unit or even in the amp could have recently gone bad...I bet if you unplug the rca halfway while the stereo is on so just the middle pin is connected it goes away...if so re ground the head unit to a frame ground and consider rerunning the rca wires away from the power cables...curious is the HU a pioneer? I had one once that went bad and started doing that out of the blue...(I suspect noise filter went)

 

yes...and i know the exact noise your talking about..ive seen alot of vehicles have it..check all your wiring like Larimie said..and make sure everything looks right..this isnt your trucks problem this is a wiring,audio issue..usually caused by a bad wire,a bad channel on a amp, or a bad rca feed

 

thanks for the info...i doubt its the amp itself due to the fact that it still pounds the same as it did, and i just bought it 5 months ago. theres no problem with the audio it works the same just has the added noise underneath.