Out of phase stereo test tone

Here you go

Windows playback “audio enhancements” can introduce cross-over between left & right channels
https://support.microsoft.com/en-gb/topic/disable-audio-enhancements-0ec686c4-8d79-4588-b7e7-9287dd296f72

[ There can be a second layer of audio-enhancements which need to be disabled. ]