While using headphones with iPad, you can check whether the audio level is OK by viewing the Hearing control in Control Center. In the Health app, you can review the history of your headphone listening habits.
If you listen to loud headphone audio for long enough to affect your hearing, iPad automatically at the top left of Control Center, then tap Add a Control.
Scroll down to Hearing Accessibility, then tap Hearing.
Tap to set a maximum decibel level that keeps your headphone audio at a comfortable level.
Headphone audio measurements are most accurate when using Apple or Beats headphones. Audio played through other headphones can be estimated based on the volume of your iPad.