Yes, you can get db Meter apps for IOS and Android
phones.
I'm definitely feeling old fashioned. Do you really need all these
technical gizmatrons? If 4-5 people in the hall say it's too loud,
then it's too loud-end of story.
How about some social engineering instead? If you find a bunch of
people who also think it's too loud, get them to tell the guy the
same thing in a short period of time. It might just sink in.
Attendance and "room noise" make a big
difference -- when you have
a lot of people you seed more volume.
When you have a lot of people they also need to listen more and be
respectful. Perhaps that's a hard sell in some areas.
I agree that the level can add to the excitement BUT it can also get
on people's nerves in a way that's not always conscious. I prefer a
level that various throughout the evening to give people a break.
Tom