I’m willing to bet a new calibrated USB mic is more accurate as well then a radio shack old style one. specially used.
Oh, they are good, but also kind of a PITA to use. I mean, I have 2. Still got to drag out the stand, the cable and the software.
I mean, if you are making speakers or attempting to measure the decay rate of the room, USB mic is the way to go. If you just want to say calibrate a HT system or integrate a sub, the cheap one I suggested is the way to go, and they actually DO have better range in Hz compared to the SPL meters and with the calibration file are really good.
Of course, none of these will come with OSHA certs. :)