This script can play a soundfile of your choice on the speakers of your choice at the volume of your choice and can be executed by task scheduler.
- download the .ps1 script
- edit it, change the variables to your desired settings (path to soundfile, speakers the sound should be played on, volume in percent) and save it
- create a task in task scheduler that runs the script whenever you start the PC and sign in
- Changing volume with powershell: https://stackoverflow.com/a/19348221
- Set audio device with powershell: https://github.com/WHumphreys/Powershell-Default-Audio-Device-Changer
- Get audio file length with powershell: https://superuser.com/a/704585