Frustrated Classical Guitar Player, hissing in recording of classical guitar Options

[johnnyboy]

I am using a RODE condenser "studio selection" microphone to record Classical guitar. I am using it with presonus firebox on garage band. The reverb effects and all sound great, but I get this hissing sound in the background. Is this normal, or do I need to do something to eliminate it. I was thinking about trying to record in the bathroom where the acoustics were better, just kind of a pain to set up there. Any advice would be appreciated