Sound Card: HDA Intel PCH/ Realtech ACL236
Big list of fixups for different models using ACL chips: https://docs.kernel.org/sound/hd-audio/models.html
Activating fixups:
Create a file /etc/modprobe.d/hda-model.conf if it does not exist.
Add a line options snd-hda-intel model=dell-headset-multi (other model variants are described here https://docs.kernel.org/sound/hd-audio/models.html)
Save file.
Restart PC.
Source: https://www.reddit.com/r/linuxquestions/comments/11x3s4o/comment/k4k5qak/
Testing first with:
arecord -d 5 -f dat mic-test.wav
To playback:
aplay mic-test.wav
^the above will save to your current directory
Testing second with Discord mic check. Echo cancelation, noise suppression, and automatic gain control turned off.
Testing results:
limit-mic-boost - Internal mic boost is either off or on, 0dB/+12dB, total volume 63%/100% https://ibb.co/v1qxKDp In quiet environment mic has good quality, but fans are easily picked up. Crackling and ugly fan noise when boostis set at +12. Discord results are similar, except much more muffled and distant sounding. Voice sounds like it's across the room and fan 'static' is softened.