We currently use this method and it seems to work about 90% of the time. Do you know of a full proof tester that will take the guess work out of the equations? Im looking to take the human error factor away.
While not impossible to "remove" the human factor it may become cost and time prohibitive to do so. You need a
As others mentioned, tone sweep will tell you most of what you need to know. Combine with a FFT measurement will tell you if it's in the ballpark.
Establish a test procedure- This area of the warehouse, this location, this mic, etc then document it. Make initial captures of your inventory, using serial or inventory numbers to keep track. You're not going to get laboratory results but that's not what you're looking for- you're looking for the trends in magnitude response, not necessarily absolute measurements. If the speaker passes the tone test, the FFT compared to a previous trace will show any other problems fairly clearly, such as a polarity reverse, drivers lower in level or non functional, passive components damaged etc.
For lack of a better and easier test I've made this work for as long as I've been using Smaart, It's very eye opening when problems do pop up, and it's a great way to learn how to make a good measurement and use discretion when in the field.