How to set channel balance in amixer?

[GitHub issues - opened <github@xxxxxxxxxxxxxxxx>]

alsa-project/alsa-utils issue #73 was opened from quantum-booty:

When I change volumn using keyboard media keys, the left and right channel becomes imbalanced. 
![image](https://user-images.githubusercontent.com/28958399/101188833-23befc00-364e-11eb-8816-efd94b9514d4.png)
I currently have this mapping in i3, I would like to add command to balance the channels after I change the volumn.
bindsym XF86AudioRaiseVolume exec --no-startup-id "amixer set Master '5%+,5%+'"

Issue URL     : https://github.com/alsa-project/alsa-utils/issues/73
Repository URL: https://github.com/alsa-project/alsa-utils