Any alternative to Radio Shack sound level meter?


MIne is kaput. I want to use to optimize sub setup.
oldears
Absolutely. Use a $20 calibrated mini-mic:

https://amzn.to/2XxZ4bl

Requires a normal headphone/mic plug on your phone. I use AudioTools on Android. You go to the manufacturer’s website, and copy the calibration file to your phone.

Best,

E
There are several iPhone apps that work very well and are free or a few dollars.

RTA Audio Pro, , RTA    ( also spectrum analyzer)

Decibel X, dB meter Pro    (can be calibrated)