A virtual device refers to the use of AudioServerPlugIn to create a nullAudio, similar to the open-source BlackHole. As you mentioned: for synchronized audio, the CoreAudio API AudioHardwareCreateAggregateDevice is used to create an aggregate device. I did this, and it was successful. However, when I switch the microphone mode to the voice enhancement mode, the number of input channels I retrieve from the aggregate device is incorrect. The specific issue can be seen in the following two help posts: https://stackoverflow.com/questions/79319480/mac-audio-software-aggregate-device-issue https://developer.apple.com/forums/thread/771690 Therefore, I had to abandon the aggregate device and use separate devices to capture and forward the audio. But this led to synchronization issues. @Systems Engineer

Have you realized it? Now I want to implement this feature, but I can't find any clues. I asked Apple TSI, but they responded： Thank you for contacting Apple Developer Technical Support (DTS). We have reviewed your request and have concluded that there is no supported way to achieve the desired functionality given the currently shipping system configurations.