ST has confused this a little. There are two types of audio players in ST:
- Audio file players (e.g. they playback MP3 files)
- Audio text players or TTS - Text to speech players (they convert text to an audio notification)
Most of ST’s built in apps have migrated to the first option, so if you device doesn’t play mp3 or audio files it won’t work. Example as such an Alexa.
Sonos, Bose, Alexa (using Echo Speaks) are examples of devices which support TTS or option 2. There are a bunch of apps available on the community which allow to use both options 1 and 2 depending on what your device supports. Here’s an topic that lists some of those apps:
FAQ: Set up Custom Chimes/Voice Notification When Door is Opened
Also check out this topic for Google home notifications:
[Release] Google Assistant Relay V2.0 - Google Home Audio Notifications!