opensoundmeter

Install command: 
brew install --cask opensoundmeter

Name: Open Sound Meter

Sound measurement application for tuning audio systems in real-time

https://opensoundmeter.com/

Cask JSON API: /api/cask/opensoundmeter.json

Cask code: opensoundmeter.rb on GitHub

Current version: 1.5

Requirements: macOS >= 10.12

Versions:

Intel tahoe 1.5
sequoia 1.5
sonoma 1.5
ventura 1.5
monterey 1.5
big sur 1.5
catalina 1.5
mojave 1.5
high sierra 1.5
sierra 1.5

Analytics:

Installs (30 days)
opensoundmeter 7
Installs (90 days)
opensoundmeter 32
Installs (365 days)
opensoundmeter 120