Connection problem with 2nd monitor

[jonh229]

27" Intel iMac using external display 32" Samsung connected to iMac via usb-c to hdmi dongle on back of the iMac.
I usually have external monitor powered off. I use it only as a monitor, the wifi is not set up nor is any of the other "features" of the Samsung.

I have one problem with the sound. Telephone calls. They work fine is I unplug the hdmi connection. If the external monitor is on it works ok but not great. But with the Samsung monitor turned off there is no mic or sound on the Mac. I am unable to find any settings to change this condition.

All other sound features on the iMac work fine when the Samsung is powered off. Only the telephone and/or Facetime don't work unless I unplug the cable to the dongle.

 

[Bigwaff]

I am unable to find any settings to change this condition.

Launch FaceTime. Select menu Video. You should see entries for your connected camera and microphone devices. The checked devices are the devices currently in use.

 

[jonh229]

Select menu Video.

Thank you, thank you, thank you. I've read everything I could find but never noticed the menu for FT. Probably because I don't use FT and so it's rarely opened. The speaker was set to the external monitor. Now I'm at sys settings.