unwanted sub noise

[jackass1989]

heya, hope someone can help me, i have fitted a vibe pulse 10inch sub in my mk2 golf, and everynow and then their is thudding noise coming from the sub , it sometimes happens when the engine is off and also when it is on, but it does not happen all the time , just time to time, is only noticeable when the music is low but when i turn it up, i think the bass from the song just drowns it out, my m8 said something about engine noise but im not sure, could anyone help

 thanks
Jack

[tommk3cab]

when you say thud, is it one sudden massive thud, then nothing, back to normal? or like a continuous thing? like a small rythmic thud thud thud?

would you say the noise, when its there, goes in time with the engine?

if its just a single massive thud it sounds like you have dodgy RCA ( or other ) connections to me.

how loud a noise is it? like the full vollume of the sub or a real quiet but deep popping noise. its just your description of a thud but only audable at low vollume is a bit confusing! I think I know what you mean though.

has you ever noticed any noise through your normal HU speakers ( if you are running any)

did you fit it all?

was all the wiring and equiptment brand new?


from what you say I wouldnt say it was engine noise. especially as you say it does it with the engine off! just to clarify, its never done it with the actual stereo off? because that is not a good sign!

[jackass1989]

chers m8 for replying , what it is is a continuous thudding, like yeah a small ryhmic thud thud thud, the noise isnt very loud but noticeable , its a rather deep popping sound. the only time it has happened without the stereo being on is when i turned the igntion off but i left my lights on and the thudding was still hapening( this really confused me), i think its sorted now tho, as it hasnt done it for a while. and yes i did fit everything myself, and i have run all the cables down the same side of the car . even though it has gone away, do u know what it could be incase it comes back. I also have 4 speakers running off the head unit and they dont have any thudding sounds. as it sometimes happens without engine running all i can think it could be is a dodgy amp, or maybe as the cables are running down the same side some interferance? not sure m8.

[tommk3cab]

apparantly cables running together ( namely the RCA's and power) can cause interferance although I have heared many systems with the wiring this way and never experienced it. if it comes back, post back and Ill help more. without it doing it it will be hard to stop it, if that makes sense.

where and how is the amp earthed as this causes a lot of problems if its not done absolutly spot on.

the metal needs to be shining, clean and the wire held  down very tight. certain points are bad to earth off too because they can be what is called not a 'true' earth. this means it is an earth but through something else, not direct to chassis, so it could be like a welded plate or something like that.

have you noticed it does it at all when you adjust the volume on the HU or....

when a CD spins up does it like tick and whirrr?

[jackass1989]

cheers for help m8, what ill do is seperate the cables and see if the nosie comes back, cheers for help, and ill re-post if i get any trouble again, cheers again mush much apreciated. also what my cd doesnt tick and whirr, but what would it mean if it did? just curious.

[Uruk Hai]

I would advise running the rca cables down the passengers side of the car and the live wire down the drivers side because the fuel pump is on that side, the further the signal cables are away from sources of electricity the better ! (Thats my opinion anyway  )

[tommk3cab]

no problem,

if you can hear your Cds spin up and/or there is like a popping sound when you turn the vollume up and down then there is a problem with your headunit, usually the earth wire. but the stereo may need to be on very loud to hear the cds spinning ( and being read) depending how bad the problem is, but popping when the vollume is adjusted will definately be noticed and will get louder with the volume of the stereo.

the cd's spinning kind of sounds similar to an old modem trying to connect, if you know what i mean by that! like a fast ticking and slight screech, but only usually when it is on very loud.

if the wiring to your HU is messed up you can get some nasty noises.

[tommk3cab]

I would advise running the rca cables down the passengers side of the car and the live wire down the drivers side because the fuel pump is on that side, the further the signal cables are away from sources of electricity the better ! (Thats my opinion anyway  )

but the fuel pump isnt working when the car is off? well it does but for only a very short time before the car starts.

[Uruk Hai]

I'm aware of that, just trying to eliminate all possible problems (cheapest first  )

[tommk3cab]

I would go for less unnessercery effort!