Sound meter app for monitoring & influencing appropriate speech loudness

[I'm not deaf]

I selected the user name, 'I'm not deaf', as it relates to the dilemma for which I joined this forum. You see, my wife & daughter, both tend to speak much louder than necessary, and neither seem aware of their dysphonia. My two other children speak at normal levels, so it's unlikely a matter of me simply being too sensitive. I recently decided that, perhaps, a sound meter app would be the only way to help the louder ones (and my dealing with them). This app should not only record the various sound levels attained during conversation, but also alert the loud speaker when he/she reaches a preset decibel level. Some of the apps I've seen offer visual alerts; vibrations, or audible alerts would be better still. Rather than review dozens of speech & education related apps (and, possibly, still not find what I'm looking for), I decided to share my concern with you, in the hope that someone can lead me in the right direction. By the way, we're looking for an iOS app. Thank you in advance.

[experienced_needpaper]

"Too loud - noise meter & timer"

It has a visual, but if you speak louder than the setting (which is adjustable with free version) the app makes a glass breaking sound.