Go with the Rat Shack digital meter [I don't know if they still make the analog meter]. Make sure that the 9V battery is fresh, since a weak battery will affect your readings.
Also, Rives make a frequency response test CD with two set of tests. One set of tests has been specifically recorded to compensate for inaccuracies in the Rat Shack meter [Note: I am not affiliated with, nor do I have any financial interest in either of these two companies!]
I think that the Rat Shack unit is really easy to use and fun, too! I showed the landscapers why they were smart to use ear protection while operating their wood chipper....peak readings of 109 dB!
Also, Rives make a frequency response test CD with two set of tests. One set of tests has been specifically recorded to compensate for inaccuracies in the Rat Shack meter [Note: I am not affiliated with, nor do I have any financial interest in either of these two companies!]
I think that the Rat Shack unit is really easy to use and fun, too! I showed the landscapers why they were smart to use ear protection while operating their wood chipper....peak readings of 109 dB!