Windows 10: Lenovo T480 speakers playing low audio, headphone jack not playing audio, speakers play no...

A couple weeks ago I purchased a refurbished Lenovo T480 laptop with Windows 10 on Amazon. I know, I know buyer beware, but I think this might be more of a recent software issue than a hardware issue. All was running smoothly with the laptop until about a week in, when during a zoom call of all things, my headphones started degrading in audio quality until it was almost inaudible while using them.Speaker audio was fine so far. Afterwards I restarted my computer and everything seemed okay again. But after a little while the audio quality degraded again while using the headphones. I restarted an

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Audio playing through speakers and headphones.

My audio is playing through speakers and headphones. I've tried to set headphones to default but the option to do so isn't there. All I have is realtek audio speakers. How do I get it to automatically disable speakers when headphones are plugged in?

 

Audio is playing out both my speakers and headphones

Open Realtek Audio Manager in Control Panel:

 

Audio is playing out both my speakers and headphones


My computer uses the Realtek HD Audio Manager. I have headphones plugged into the front panel and speakers plugged into the board itself on the back. I use nircmd to switch the default audio device between the speakers and headphones.

When I have the headphones set as the default device, audio plays out only the headphones. When the speakers are the default device, audio plays out both the speakers and the headphones. I can't figure out how to actually disable audio from the headphones when the speakers are the default device (short of disabling the actual device or unplugging it).

How can I properly disable the headphones when I want to use the speakers?