5490 AIO, Microphone Jack Input Warbles.

The title isn't quite accurate, but here's my situation.

The live streaming system is in a church. The microphone is plugged into the headset/microphone port. Audio from someone talking 100+ feet away is clear and crisp. Also singing of a few voices is crisp and accurate. But when the organ plays, the audio will warble, especially when loud chords are held for longer than just a touch. I'll grant that organ music is intense and loud, but I'd think that the system should reproduce the sound accurately.

It sounds as if the Realtek subsystem may have an automatic volume control algorithm. My reasoning is that a chord will start at the expected intensity, then suddenly back off in volume almost to silence, then restore volume part way, then start searching again. As I said, it warbles, but not consistently.

If the system, Realtek or Windows, does have an automatic volume control, is there a way I can disable it?

BTW, this did not occur with a previous camera that embedded the audio within an IP stream coming into the computer through the Ethernet port as an Internet website download. I don't know how audio from the Internet is handled within the computer, though obviously differently than audio coming through the mike jack.

Thanks for any suggestions, Hank