How to output audio to multiple devices in Windows 11?

Thanks! VoiceMeeter works really well! That was the solution.

What you want is ASIO4ALL, which allows you to create an aggregate device in Windows much like osx. You can get the software here asio4all.org. You need version 2,14 which is on page 2. Then install the offline component this will give you the control panel. Launch it and pick any audio device that you want to output to at the same time. It can be a DAC external USB device internal sound card so forth. You may need to adjust the audio buffer. Wala you now have an aggregate device you can use in any game or app and will output to both sets or any number of outputs you desire.

So, is there is no way to pass the same audio output to two different output devices with Windows 10/11 sound.

Output #1: A line out on installed card to a stereo speaker system.

Output #2: Bluetooth audio headphones to monitor the #1output feed.

Example: I cut the line-out house stereo for a moment, I would like to continue monitor the feed with headphones and vice versa.

This was a configuration that I had used at one time with a Win 7 box and 2 SB sound cards.

No he is right. No one wants to use 2 soundcards, because that is stupid. You are the outlier, the odd one out. Most people will never have a use for 2 sound cards. Just because you seem to think you need them, doesn't mean that anyone else ever would. This comment wasn't helpful at all, and really just made you sound like a douche bag.

You can direct individual apps to output to different audio devices. As this screenshot is shown, the default speaker is the realtek 3.5mm computer speakers and I directed my browser audio to my monitor's speakers.