Watch the video:
Timestamps:
0:00 - Intro/Explanation
0:15 - The problem
0:35 - Download VoiceMeeter
1:30 - VoiceMeeter Potato layout
2:13 - Select VoiceMeeter as sound output
3:50 - Playing audio through multiple devices at once
4:50 - Adding more speakers/headphones to use at the same time
5:25 - Fix possible issuesWant your sound to go to Speakers & Headphones at the same time? Multiple headphones with one app? This guide shows you one of the most powerful tools for rerouting & multi-output for audio on Windows!
VoiceMeeter: https://vb-audio.com/Voicemeeter/potato.htm
