How to set Flash Player to use alternate sound device?

How is the Flash Player configured to use a different sound output device? The default sound device goes to small speakers on the computer. There is an alternate sound device that connects to a high quality audio system via SPDIF. I don't want to set the system-wide default audio to the output going to the audio system because it is not turned on all the time. I have configured specific media appications to play through the audio system, but I want the "default sounds" from the computer to use the computer speakers.

I can't find the settings in the Flash Player to cause it to use the alternate sound device. There is a settings dialog that includes exactly the necessary settings for a microphone (allowing a choice from any devices). Where is the setting for speakers?