There is a noticable hum in my Ibanez GSR180 Bass (two jazz type single coil passive pickups model). Strange thing is when I hold it in playing position there is a noticable hum but when I hold it parallel to the floor it all goes away (both pickups turned on to %100) I believe it is properly grounded now becuase there was a grounding issue before and it is fixed now. Everything that needed to be grounded is grounded now. Any ideas? Edit: this seems to be the answer. I'm not looking for solutions. Just wondered why.