Hi guys, not sure where this post belongs, figured I'd try here.
So I have an 01 WRX, with a pioneer headunit installed by the previous owner, there is no amp at this stage. I believe the unit is an AVH-X2600BT, or something very similar from pictures I can track down.
I began to notice the left-front speaker emits a static like noise/whine, and that the left speaker is louder than the right and requires a bit of balancing to level the left and right. The noise increases with speed, but not RPM. It can be drowned out easily by mild volume, but at mute is somewhat noticeable, particularly as speed increases as it only comes from the left. The rear speakers appear to be the same volume when the balance is centered.
I have installed 2 new front speakers, as I I thought this may fix the issue. The right speaker is louder, but still about 10% quieter. The hiss/whine from the left persists. I have also done a grounding kit in the engine bay and tried grounding the head unit to the chassis. I have spoken to a few local audio people, they have suggested that the HU itself is perhaps blown.
I now have a noise filter, but before I put that in, I thought I would seek out some further advice in case there is something I am overlooking. I figure that a filter may stop the noise, but not help with the volume issue. I am not very knowledgeable with wiring or car audio, but if there is a possible fix I'm willing to try it before having to fork out on a new head unit.
Thanks in advance