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.
LoL, perhaps they lack a crossover. And are you hooking the rear speakers to the same chn as the fronts when doing this. A stupid question I know, but cha never know.
The power output of your head unit is false! Your fronts sound better when the rears are dissconnected because because your head unit is only powering two speakers. I agree with Nicolas Obando, you deffinately need to use a crossover to seperate the front mids and the tweeters. To stop the crackeling, you need a Four channel amp. Preferably one that is at least 40x4 RMS (That means you will have AT LEAST 40 watts to each channel) do not bother with the MAX power rating unless you are using EXTREMELY cheep speakers. If the crackeling continues, your fronts are toast!