I have Logic audio with both os 9 and os 10. If, for example, I am singing into a microphone and the input goes into the mac. I have audio track 1 set. In audio track I choose Bus 1 and set bus 1 to "pre". In the os 9 version of logic, I can hear my voice with the effect that I choose (Reverb, for example). In the os x version, I can hear my voice as I monitor but I can't hear the effect. I am doing exactly the same thing on both platforms but only hear the effect while monitoring in the os 9 version. I have turned "monitoring" on and off in the "audio hardware" window as some have suggested but to no avail. Has anyone experienced something like this? Any thoughts? Someone suggested that it might be the driver for my Midiman Duo, hence the reason for turning off the "monitoring" option.