Telekinesis said:
I've seen unsuppressed pistols metering at 159-160 dB, so I would question whoever published the data that a .223 would be 155.5 dB.
Several pistols are in fact louder in terms of decibels than intermediate caliber rifles and longer shotguns.
This is because of the much shorter barrel. Even just a few inches can drastically change decibel levels at certain points in a pressure curve.
However what the db reading does not tell you is how long the sound impulse is. Rather the db reading is the greatest db level reached.
The greater volume of gas from a rifle still is often more damaging because there is more of it, and the length of the sound from each shot is longer.
A longer impulse at high db levels can be more damaging to hearing than a shorter one even if it goes a little higher.
Even though we may perceive gunshots as being of the same length, they are not, and the size of the pressure wave and the duration of its effect on the ear is greater in some than others.
But there is yet another concern. Higher frequency reports tend to cause damage faster than lower ones even at similar decibel levels.
So even a similar decibel rifle will typically be more damaging to the hearing than a shotgun because it is creating a higher pitch noise.
The same can be said for handguns. Some produce a deeper boom, and some are more high pitched report.
Finally what is indoors makes a difference as well.
Hard surfaces reflect sound the best. Your typical indoor range with dividing stalls is probably one of the worst for sound for example because of all the hard surfaces bouncing sound around at near peak levels.
Hard surfaces are easy to clean, and why they are used where you need to clean, mop, disinfect, deal with liquids or spills, clean up lead etc, but they also reflect sound. If you can hear a hollow sound or echo in a room it clearly reflects sound really well.
The difference between an unfurnished home and a furnished home is also quite obvious if you make a little noise, fewer things to absorb sound in an unfurnished home, and more flat surfaces to reflect it back at an intact wave.
In a home someone is living in many rooms are often carpeted, and have soft items and upholstery that reflects sound back at greatly reduced levels, while others reflect it back at greater levels.
Rooms with linoleum and tile would be bad, and wood floors a little better but worse than carpet.
A tile bathroom of typical dimensions with small space, typically few objects that would absorb sound, and hard surfaces all around, would be the worst.
A kitchen only a little better.
A carpeted and furnished living room likely the least damaging.
So the level of damage would also depend on the room. If you are in the tub (one of the safest locations from bullets in many homes) you will probably have the most hearing damage from discharging a firearm.
The same acoustic qualities are also why some people enjoy singing in the shower, they will sound much better to themselves.