Trouble getting voice chat to use Bluetooth while other sound uses my speakers

I have a usb earpiece that I like to use for voice chat but I like to keep the other sounds through the speakers. I know there’s a setting in the sound options that allows you to select a different device for voice chat but I find this only works maybe one in ten times. The little green voice chat icons come on properly but I can’t hear anything - it’s like the volume for the voice chat device is turned all the way down. I have occasionally managed to get it to work by muting and unmuting things from the windows control panel but this no longer does the trick.

Any suggestions?