iMac iTunes playback screeching sound at end of song

My iMac (5K, 27" 2017) with macOS Catalina, has a HORRIBLE SCREECHING song, for just a split second at the end of songs. It doesn't matter if a downloaded playlist or album, or, playlist or album on Apple Music. This doesn't happen every time, but very often. The screech sounds like extremely loud bus brakes and is only at the end of a song. It does not happen on the same playlist, album or song on any other device (iPad, iPhone or MacBook Pro), only my iMac.

I have tried to use my little-used MacBook Pro for Music but it is too old (1999) to support newer software updates. I want the convenience of control, controlling music on my iMac while using the iMac; it is my main device.

Any idea how to fix? I've looking casually through help topics and see nothing like this. Also, I am not real technically inclined, so please talk to me like I'm 70 (I am 70).

Thank you,

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