new user and new car audio

Hello all. I've been reading this forum for a while now, and decided to register, so hello to all. The aim of this post is to get some info on wiring and sorts of stuff.. So here goes the story: My wifes sister gifted me a car an 91yr. Fiat Tipo :) yeah its old i know. But its quite nice since repairs do not cost much and so... So i almost made it to the exelent condition and decided to put some nice Audio into it :) So i bought 2 front speakers Boschman(lil' ones i dont remember what power they have) also 2 rear speakers "Magnat" each of them is 260W(well atleast they say so =) but i think they lie). Also i Bought Pioneer DEHP4950 HU and a Capacitor for 1Farad. I'm not really into those shortnings since i know some electronics but most of it is about PCs :) so if you write me an answer, write all the word please :) I already had and amp which i believe is "made in china" its called Autostar but as i tried to find some info on it i couldnt find anything :) so prolly its fake or something but it works atleast. So we did all the wiring install stuff and yesterday we managed to make all these thing work together however i did not try to install capacitor yet. The amp has two 20a fuses, and it is written that its 3kW but i know its not true. I just thought that maybe it would be better to run sound through it. But when we installed all of it, and pluged all in. I think the engine was off so we tried to find some radio station and then we realised that strange sound comming out of the front speakers so i went to the amp and started to rotate swithes on amp, there are two of them one that makes sound louder and another i dunno what it does :) (as i said i'm not really into audio systems) so when i made second switch to the minimum the strange sound dissappeared. I tried it on the rear speakers but they didnt seem to make such noise as front ones. When we were intalling the wiring the RCA cable and 12v cable are all in the same place(i've read that it can be that if those two are close to each other you can hear that noise). The difference between those is that front speakers have thicker cable and it is installed along with RCAs, 12V, remote control and    rear ones are thiner(alot thiner) but they are not near those RCAs or front speaker wirings. I'll try checking ground connection today and install another cable. However i cant distinguish whether its a bad ground or a bad RCA. RCAs that i bought were made for PC<->Music Center; DVD<->Home video things so i thought that they would be ok, also they look just as normal ones, not as those crazy thick ones that are expensive :). Sorry for the long post but i hope i will hear some advice from you. Thank you in advance :)

Run the front RCA's along side the rear RCA's and your problem is solved. When you turn up the GAIN knob ( this is like a volume knob for your amplifier ) it increase the volume of the sound but also increases the volume of any kind of noise that is picked up from the RCA's.Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

I re-done the wirings yesterday. I think now it should be ok since i bought better RCAs designet for car audio. But i did not test it today since i had to give my car to service on breaking system. i'll try to plug everything in today and write results that i got :)

it seems that installing new wires in a proper way did not help. when the engine is off. everything is ok when it is on, there is strange noise coming out of the speakers, maybe its because of a poor ground or something ? please help :( P.s. I did change RCAs to a new good quality ones and so on.

Regarding to the noise. with new wires i think it much lower than before. i will try to unplug antenna today also reground my CD player and check the resistance on amp<->ground. I'll post results later. Any comments would be nice :) right now my cd player grounded to the cars ground(not chasis as it is intended to be) as it was the oem one(the old little black wire:) ). maybe this could also be causing the noise i'll see what i can do today :) By the way could it be that if the battery is poorly grounded(maybe the wire it self is old and need replacement) could be causing this noise ?

I just checked RCAs they seem to be fine as i plugged them directly so nothing would interfere. Also i noticed that when i set volume to 0 only that strange sound persists. So any ideas on that is it ground or is it something else like my HU(i read that pioneers have problems with these things)

Today i tried plugging only one channel(rear or front one) and it seems that if only one is plugged in everything is Ok. If i plug all in that noise comes up but it is only while engine is on, when engine is off and i plug all channels in the sound is no more :/ any ideas? maybe i need a crossover? or a sound filter?

Ground the outer shield of the RCA and see if the noise is gone.Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

and how do i do that ? :) i have no idea of how this is done :))

no answer in several days ? :( please people help me, because i really don't know how to do it :(