engine noise in speakers

[chezz]

What kind of speakers are you using - Standard OEM?

[chezz]

I may be way off here... Am I right in saying the rear speakers are active - if you mistakenly try and put a massively amplified signal to them then you have a major problem - active speakers have the amps built into the speaker...

[hunker7]

I'll check what speakers i have at the rear, as they came with the car and I used my own front speakers, but they are not OEM.

[newsh]

Sounds like the head unit has a bad ground or is grounding through the aerial cable.

[hunker7]

I tried grounding headunit somewhere else, didn't work.

[igor136]

I think the problem is in amplifier. Poor quality. Try without

[hunker7]

I think the problem is in amplifier. Poor quality. Try without

Had the amp connected before in the other car and it was fine, but when i connected the phonw it sounded brilliant.

[igor136]

There are a nuisance ( interference) and an amplifier is not able to eliminate. Maybe DC alternator is not ideal or so.

[johne]

Had the amp connected before in the other car and it was fine, but when i connected the phonw it sounded brilliant.

So the amp and speakers are good on their own and it's not the amp.

When you had it connected in another car was it the same amp and head unit? If the head unit was different and the ground loop isolator doesn't work well between the two maybe the head unit doesn't like driving that amplifier or ground loop isolator and the head unit isn't set up to drive an external amplifier rather than say speakers connected directly to it.

Does the head unit have any other audio connected to it like a remote CD player?

John

[hunker7]

Same amp, same head unit, only rear speakers are different. What i will try is disconnect head unit from car's factory wiring and get new earth, new 13v and see if that fixes the problem.

[Ironman80]

What i will try is disconnect head unit from car's factory wiring and get new earth, new 13v and see if that fixes the problem.

Try it from same point as amplifier.

[hunker7]

Sorted! It was the head unit after-all. I guess there was something wrong with the RCA inside the head unit that was paying up, because it worked ok without the amp. Now sound is so much better with the new head unit

Thanks for all the help and suggestions