Hey there, let's get to the bottom of why OBS is still capturing your screen when you only want audio! Here are some practical steps to fix this:

• Double-check your scene sources
  You mentioned creating a new scene and only adding an Audio Capture Device, but sometimes OBS might have default sources (like Display Capture) lurking in there without you noticing. Open your target scene, look at the Sources panel on the bottom left, and delete any non-audio sources (like display/window captures). Make sure only your ALSA or PulseAudio audio capture device remains.

• Adjust your recording output settings
  Even if your scene only has audio, if your output format is set to a video type, OBS might still generate a video file with a black screen. Head to File > Settings > Output, go to the Recording tab, and change the Output Format to a pure audio format like MP3, AAC, or FLAC. This guarantees your output will only be an audio file, no matter what.

• Check for global sources
  OBS has a "Global Sources" feature that adds a source to every scene automatically. Click the dropdown menu in the Sources panel and see if there are any video-related global sources. If there are, either remove them or disable them—this way they won't show up in your audio-only recording scene.

• Do a quick preview test
  Before hitting "Start Recording", click the Preview Stream button. If the preview window is completely black (no visible screen content), that means only your audio source is active. Now you can start recording confidently knowing it'll only capture audio.

备注：内容来源于stack exchange，提问作者Juandev