Why are you using headphones at all? Are you overdubbing? Even if you aren't the one playing headphones aren't the best reference for positioning the mic or setting EQ or compression. Get a ruler and do one long test track with the microphone in several positions. Announce the measurement before you play the test music. Then listen through your monitors. Much better way to decide on placement. You can do basically the same thing with the DSP eq and compression, but if you are pretty new to this you can learn more playing with the plugins in logic while listening through monitors. Are the plugins in the microbook that much better than the ones in logic?