Fun experiments with sound

We’ve often sought more quantitative measures of noise levels in RVA restaurants, as opposed to subjective descriptors. In the absence of a real sound meter, I’ve been playing with the Sound Meter app for Android over the last year or so. The app uses the phone mic to estimate the sound levels which is output in decibels (dB). See numbers on the left and their corresponding levels.

Note that the decibel scale is a log scale. Thus an increase in dB by ~3 dB is a doubling of sound intensity. An increase in sound intensity by 10x = 10 dB. So going from 60 to 80 dB is actually an increase of 100x in sound intensity!! We of course, tend to register sound differently in our ears (based on pressure which is roughly 6 dB for 2x sound), which makes the numbers tricky.
 
So what was the measure of sound in RVA restaurants? 

   
The results: Overall, this app turned out to be quite finicky and I’m still not sure about its accuracy. Some control experiments included a VCU Rams Basketball Game and next to a prop jet airplane (both very loud over 80 dB but did not exceed 90 dB) to a quiet room ranging from 40-60 dB. 

After collecting multiple data points in several restaurants, rather surreptitiously of course :), I ended up with numbers with little to no statistical significance (p-value)! So I finally throw in the towel on this experiment. The (rather obvious) data – most restaurants typically have levels between 55 dB – 75 dB, with wide fluctuations as a function of time!

Verdict – need a better sound meter. The app is fun though!!

As an example, the WaPo has used the following QCME scale to describe restaurant noise levels for some time now:

Quiet (under 60 decibels)
Conversation is easy (60-70 decibels)
Must speak with raised voice (71-80 decibels)
Extremely loud (over 80 decibels)

Within this data set, I can however crown the winner for the average quietest dining room we’ve encountered here in RVA. Quiet drumroll.........No surprise here – on average, the dining room at the Lemaire was the best place to carry out a conversation in hushed tones (averaging 55-65 dB).

The bar at the Lemaire, on the other hand….

(PS: While dining acoustics are indeed important,  this "experiment" was all in jest. Its bad enough to have people like me taking pictures of food !!)