Speech unrecognizable when watching movies

[Lumaja]

Motherboard: Asus Prime H410M-K
OS: Linux Mint 20.3

These motherboard is newly installed and was working properly yesterday notice
while watching a movie with earphones found the speech very bad and unrecognizable, sounds like the speaker is inside of water like in a pool.
I check the settings and all seems right.
Playing music found I can ear the music but the singing is unrecognizable.
With USB speakers the singing from music and the speech from movies sounds good.
I have a old HP laptop with Linux Mint 20.3
After I notice the problem I checked the earphone cable on HP laptop found working properly
Can some help me to correct this.
Thank you

[standardnerd]

Try the alsamixer utility from the console. It sounds like there's some kind of surround sound stuff going on but you've only got stereo headphones.

[OhioYJ]

These motherboard is newly installed and was working properly yesterday notice.....Can some help me to correct this.

What are you using to play audio / video? Was it after a kernel update? I had a similar issue with a Realtek chipset on my motherboard. My sound would be out of sync, and stutter. It would only work in very specific kernels. Other PCs with different hardware, worked fine.

My solution was this. (last post in that thread)

[rene]

[ .. ] found the speech very bad and unrecognizable, sounds like the speaker is inside of water like in a pool [ ... ] Playing music found I can ear the music but the singing is unrecognizable.

By this description I can full-on guarantee that you have a hardware issue, specifically, a bad/lose ground contact: the stereo signal is differentially encoded, and vocals being placed in the middle of the stereo mix they cancel out.

Usually it is a simple issue of not having the plug in deep enough (or maybe too deep). If not it'll be a dirty socket; you'd if you'd have it available use some alcohol or alike on the plug and plug/unplug/twirl the plug into the socket a fair number of times to clean off gunk.