How are the correction factors arrived at?
How can we be sure we need to alter the regular readings?

is this a test or something?:confused:

no, it is a for real question, seems like the meters are really pretty far off from accurate, but, that far?

Radio Shack has been selling these meters for a long, long time. I'm sure that over the years almost every part and process has changed several times. Plus darn few the the "Calibration Curves" were generated with anything that was calibrated and most of the procedures used were terrible.

These meters were designed to measure general sound pressure levels, not levels of primarily deep bass sounds. They were never designed to be super accurate microphones, but they do have a fairly predictable rolloff that can be numerically compensated for. I don't who did the original tests, but this link has as much info as I can find.
http://forum.audiogon.com/cgi-bin/fr.pl?htech&983682086&openflup&1&4

And short of individually calibrating each meter indivually, which can be done for about $50, what we have are very fair macro level approximations for each model of the Radio Shack SPL meter.


Tim