I have recently noticed that when I use my Sennheiser wireless and the FMU128 drive attached to my Sony NX5U a faint re-occurring noise is being recorded. I noticed the "access" light on the drive flashing every time I hear the noise so something in the drive is causing it. When I remove the drive and record something the noise is gone. Anyone have this experience or know what is causing this? This has led to some of my friends who also have experienced this to begin using digital recorders and forgo the use of wireless altogether.