best settings for noise reduction

acoustic guitar, sure mike straight in with adapter to lap top, or run thru my Samson 4 channel mixer seems to not make much difference. what settings do you other guys use on noise removal, to rid the line noise but not effect the sound?

Here are my present settings.
noise reduction (db)13
sensitivity (db)0.17
frequency smoothing(hz)240
attack/delay time sec. 0.60

what am I doing wrong, thanks james

Post some of the work before you mess with it. Straight recording, no effects. Use very high quality MP3 to get the most music in. Include some music and a count to three silent patch where you stop playing. Hold your breath. We want to hear the noise only.