Stand by some one at the range without ear pro and ask them to shoot one shot.

The sound is only a fraction of a second but that ringing you'll hear is the death sound of the frequency you'll likely never to be able to hear again.

You also need to understand that sound and loudness isn't what causes hearing loss it's the pressure shockwave.

If a blast "noise" is mostly outside of your hearing range the pressure will still do permanent damage.

When a bomb goes off most of the energy can very well be outside of the normal frequency range of the human ear, it will still however rip your ears apart.