I've recently bought a VW Polo R reg (1998 I think).
Firstly:
I bought a new Stereo, a pretty cheap one with the following specs: Power Supply DC 11-14V Speaker Impendance 4 ohms Power Output 40W x 4
Secondly:
I've put my own speakers on the parcel shelf and hooked them up to the new stereo. The wiring is correct and allows me to fade from front to rear left to right etc..
The Problem:
When the back speakers are wired up, the front 4 (2 bass speakers built into the door, 2 tweeters on the dash) become very distorted and crackle when the volume / bass is up.
If I unplug the back speakers they are fine again.
Do I just need an amp / better car stereo, to give all speakers more power? Or could it be something else.
Try unplugging the front speakers and see if the rear ones get distorted the same. I'm not sure how amps in cd players work, but it may not be directing enough power to the front speakers when rear ones are hooked up. Either way, sounds like the speakers are fine since they do sound ok when the others are not hooked up. I'm pretty sure getting a good amp will eliminate the problem.