I hate that I'm getting deafer each year, but I can still tune a speaker or hear if one is not set up.
I worked for many years as a sound engineer for a music group and other settings. I never wore headphones as I went by the sound from the speakers. Headphones give a different sound to the speaker and it's the speaker the audience listens too.
Now although I don't do that job, and although I wear hearing aids, I hear better in a way without when setting the equalisers for speakers.
I can still hear a bum note a mile off, but can't hear someone in the room talk to me! lol
I've been known over the years, going into friend's house n changing the settings on their TV or hifi. Despite telling me off initially, mates usually thanked me a few days later. lol
As I don't really use portable speakers, I removed myself from this handout. Not speaker is truly bad, it's not got the right sound.going through it!