I have a VCR with a tape cartridge playing in it. The video output (SCART/RCA) goes from the back of the VCR into my Elgato video capturing device's RCA cables. The Elgato device is then connected via USB to my PC, capturing the video/audio as it plays.
By "RCA", I mean "RCA plugs for composite video (yellow) and stereo audio (white and red)".
When I was a kid, I for some reason used to think that VCRs had a microphone, so that you had to be perfectly quiet while recording something from a TV broadcast onto a blank tape, or else the tape's audio would get the voices/noises from the room on it, over the actual broadcast audio. Of course, this is silly. VCRs don't have any such "microphone". Why would it? But that's how my childish mind thought, until I (probably) got it explained by somebody.
But I'm still paranoid to this day that, maybe, if the sound is loud enough, or maybe physically near enough, or if I'm playing music at the same time on the computer as I'm digitizing my old tapes, it could result in some sort of subtle interference. Is this the case? Could noises from the room or from inside the computer somehow end up sticking to the signal that goes from the VCR into the Elgato device? (I listen to the music with headphones.)
After all, we are talking about analogue signals. I've heard old "separated" audio channels from the 1960s where you can faintly hear other instruments from the other channels on the vocal track, etc., so at the very least, it was a thing back then. Or maybe they didn't do it correctly. It was a Beatles song's "multitrack" tape. I'm not at all sure that the analogue/electrical signals that go out from the VCR are somehow perfectly shielded from this potential issue. That's why I'm asking.