Why does my USB audio device have problems with Google Hangouts?

The audio sent to the person I'm talking to is very faint when using my USB audio headset and Google Hangouts, even if I turn the level up high in System Preferences. In Skype, everything is normal. What could be going on?

MacBook Pro (Retina, 15-inch, Mid 2014)

10.10.2

Plantronics .Audio 478 Stereo USB Headset

Chrome

update: it seems that refreshing window (essentially re-joining the hangout) causes the correct mic to be detected.