Let me first explain why I need to achieve this - maybe this leads to an alternative solution I didn't think of.
I want to play a song through my normal speakers and an additional radio speaker. Therefore I bought an FM transmitter which I connected to my computer. On my computer, I configured my normal speakers as default audio device and tunneled my audio through the Stereo Mix recorder to my Radio transmitter, which is the Default Communication Device (see here for additional information). However, the tunnelling takes some time, which results in a slight delayed sound from my radio. My idea on how to solve this issue was to delay the output for my normal speakers, so that the sound is played simultaneously on my speakers and my radio.
I'm mainly using Spotify, but it'd be cool, if all audio output was delayed for this device. I don't care if the solution to this problem is a bit hacky or if I have to write a software for myself to accomplish this task (even though superuser wouldn't be quite the right site then) either. I'm using 64 Bit Windows 10, if you need additional information, feel free to ask.