Pulsating sound through the speakers

[demuire]

I've finished my stereo install in the Corolla, and sometimes (usually when I first turn it on or something) I get this "dup dup dup" pulsating sound through the speakers, any idea what it is?

The same problem occured when I forgot to earth the headunit and amp (cept it didn't go away obviously)

The sound usually goes away after a few seconds or if I change channels or something.

I've changed the earthing points for both the headunit and the amp, but it still does it...

Any ideas what it is, or how to fix it?

Thanks

[gti6]

Is it consistent?

I had some weird probs like that when the speaker terminals were shorting on something within the doors.

I think something is shorting.

Cheers
Adrian

[demuire]

Yeah it's a consistant "dup dup dup" sound, maybe 2 "dups" per sec? Man, I hope it's not something shorting (I have like a billion wires in there). Would it be a power shorting or a speaker output shorting?

Edit: If it is shorting, why doesn't it come back once it goes away? Once it goes away it only comes back if I turn everything off, leave it be for awhile and then turn it on... And even then it's not every time I turn it on that it happens, only once in awhile

[tomee]

hrmm could be some connection problems?? maybe ur RCA's are loose and are not connected properly?
maybe it oculd be an amp problem?
hard to tell without seeing the problem
:)

[demuire]

Well I tidied up the wires, checked the RCA's etc, everything was fine... and it hasn't recurred yet, so... *cross fingers*

Thanks :)