Yes, you can use Alexa to play your subliminal messages.
All you need is a device that has Bluetooth including your phone.
To pair your phone with Alexa, say, “Alexa, pair,” or “Alexa, Bluetooth.” Look for the Alexa speaker in the Bluetooth settings on your phone. Select it to pair and begin streaming music.
You could also use it to stream to multiple speakers, set it as an alarm to start your morning, and even create playlists for your subliminals.