I found this comment on youtube by asperous helpful: If you are on a mac you can go under accessibility -> sound -> play stereo as mono. This will balance the sound.

Plug your headphones only halfway into the jack.

Yet another brilliant argument for still using the 3.5mm jack

It was a cross between sarcasm and a reference to a previous HN discussion on phones looking to phase out the 3.5mm

Yes, I am aware, but I'm very much in favor of removing the useless jack. I have already transitioned into using bluetooth earpuds and headphones with my mobile devices and laptops, and I will never go back to cables.

This is "hacker" news after all ...

One could make a case for this feature by claiming it is an accessibility feature for the non-bilateral deaf / hard of hearing community.

As a non-bilaterally deaf person, I agree. Although TBF, I think it should be an OS-level feature built into the sound settings, instead of asking everyone else to reinvent the wheel all the time.

I feed the URL into smplayer and force the audio to mono inside the program when it's unbalanced.

Alternatively:

      mpv --audio-channels=1  https://www.youtube.com/watch?v=L5GVOFAYi8k

Thanks, this works great.