I'm using Encore on a DVD project (macOS Sierra 10.12.6) and as you know Encore can playback the timeline and preview your DVD, but for some reason I got no sound output through my brand new 24bit 48k audio interface.
In Encore, one sets the Preference/Audio/Video Out by clicking on Audio Output Device. This will open the Mac Audio Midi Setup. Click on Adobe Encore DVD 6.0 an you will see that all the devices are greyed out. Clicking and selecting your favorite device only activates it briefly, as soon as you return to Encore, all devices turn back to inactive...
Unlike Premiere Pro 6.0, it does not stick. Well the trick is to leave Adobe Encore DVD 6.0 alone, select your Audio interface/device as the System Sound Output in Mac Preferences, and in Audio Midi Setup set the device to 16bit., 24bit does not work with Encore, only 16bit.
At last! Audio output from Encore!