How do you get another headphone feed out to the director on an eng shoot? I've been working directly from the camera without a mixer. I do have a small headphone amp(ac with wall wart) I use in my home studio, with multiple inputs and could use that; but I want to keep the camera easy to move from shot to shot without another snake's nest of headphone wires and extensions to move. Do the pro location mixers have multiple headphone inputs built-in? Is there a wireless solution that's not too expensive?