The X220 has a notoriously bad internal microphone. It can be somewhat improved by making the input mono with module-remap-source
/etc/modules-load.d/microphone.conf
# make micro mono module-remap-source master=alsa_input.pci-0000_00_1b.0.analog-stereo channels=1 master_channel_map=front-left channel_map=mono
Replace master= with your device, and master_channel_map= with the device's channel
It's a bit better, although an external usb microphone is the real solution.
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