Car Stereos: Install in Hyundai XG350, hyundai xg350, added resistance

Question
I read your answers from January about the XG speakers needing power.  I followed your guidance by jumpering the radio's red wire with the red and green from the factory harness versus the blue/white.  Sounds great....but when there is no audio signal going to the speakers, i have a hissing sound.  Sounds just like when you turn the tuner up really loud before the song starts....make sense?  I am not sure where to look next.  Any thoughts?

Answer
You saved yourself a headache by doing that.  As far as hissing noise, there are a couple of things that would cause this.  First is the ground wire.  It must be as large as the power wire, as short as possible, and securely connected to a good ground point.  Then, the power wire may need a noise filter to regulate the noisy power coming from the engine.  If the hissing is there without the engine started, then it may be a case of inferior wire.  Poor wire or connections will let noise in through the added resistance of the poor materials.  Hope this helps, Scott