If you are having difficulties with your sound in Virbela, click the cog menu in the top right corner and open the Mic Settings menu.
You can choose your Microphone on this menu. Click the button with the mic you would like to use.
On Windows you can change your Speakers by clicking the "Windows Sound Settings". On Mac, please see below for further instructions.
Go to System Preferences
Go to the "Sound" subsection
Here you can choose your audio output and input
Hit the Windows key on your keyboard and type: Sound
On this Screen you can choose your speakers by clicking on the Speaker icon you would like to use and Setting as Default Device.
You may need to relaunch Virbela for it to recognize the new sound settings.