I installed the Yosemite beta on my Mac Pro (late 2013). It doesn't have a built in iSight camera, so I use a Logitech webcam as my mic. When making voice calls (or using FaceTime audio for that matter) the recipient of the call hears an echo. I don't hear it, but I believe their own voice is being played through the speaker, and transmitted back to them. This doesn't happen with internal iSight cameras as often, but apparently happens with external webcams all the time. Is there any known solution? Since the Mac Pro doesn't have an internal iSight, it would have to be a solution to prevent the problem of audio being played back from speakers and picked up by the mic. Otherwise, voice calling and FaceTime audio are almost useless for Macs without internal iSight cameras. I'd be willing to but a new mic if it would eliminate echo. Any ideas?