How loud is too loud on on IPad Mini 1?

I have a pair of Shure SE-215's and I plug them into my ipad for a metronome or other things.

I have iOS 9.2.1 and I would like to know how many bars that I can have the volume on until it starts to cause damage to my hearing.

What I mean by bars is when you press the side buttons for volume.

I'm sure all aren't the same. You would need something to find out the decibel levels and then see what the Dr.s say is safe. See if there us an app for decibels.


Update, there are several decibel meters apps

As a very rough guide, any time you have any after effect, you're doing hearing damage.