Thanks for the update on the NIOSH app. Before recommending it on this forum I did check to see if it is also available on Android phones. This search listed it fourth of five apps for Android phones: Android user apps for sound level meter - Search
If that search result is erroneous there are a number of sound level apps available for Android phones, many free and some costing a few dollars. Simply input "sound level meter" into your phone's app store.
The advantage of the NIOSH app (at least on iPhones) is that it complies with the Type 2 requirements of the IEC 61672 standard for measurements within +/- 2 dBA. So, it is more or less accurate. That said, any readings may vary based upon a host of considerations - equipment, room acoustics, distance from the loudspeaker as well as position of the phone mic, etc.
This is why I suggested that results are simply qualitative showing relative general loudness and duration. For better measurements you'll want to have a calibrated mic and software, and compliance to the extent possible to one of the published protocols, perhaps one of those available from the AES.
While I used to really enjoy trying to do the kinds of measurements you read about engineers doing, I am now in retirement and occasionally enjoy just sitting in my chair with my phone while listening and watching the numbers change. One puzzling mystery encountered from this is how I consistently get readings of 20 - 30 db in the early morning when the house is absolutely totally silent to my hearing!

