It’s a myth that headphones cause more ear damage than speakers.

95dBs measured at the eardrum are 95dBs independently if the source is 10m away or inside your ear canal.

Now most people tend to blast louder on headphones than they do on speakers, I tend to do the opposite, so in my case speakers cause more damage.

If you “just turn it high enough to hear it” then there’s no damage. In fact if you listened to speakers you would have to probably turn it louder to overcome the environment noise than you do on headphones that muffle outside noise.

If you search “OSHA dB chart” you should get a basic idea of how loud is loud, note than ear damage is cumulative, so it’s OK to blast super loud for few minutes a day, on the other hand if you listen to music all day you need to play at lower levels.

Also, listen to your body, if after a listening session you hear tinnitus (ringing in your ears), then it’s too loud. (That doesn’t mean it’s OK just because you don’t hear ringing)

I usually listen around 100dB(A) but I don’t recommend it.