President's Message
July 2007

1.  From member Vince Capizzo: I ran across this interesting series of tests the other day, and thought it was worth passing along.
It's a series of 3 tests which measure tone deafness (medically, congenital amusia), pitch perception, and rhythm. (Ignore the Google ads, and scroll down to the tests.) (WEBMASTER'S NOTE: If you use a real browser, set correctly, you won't get those)

2.  Recently I purchased new power tool and noticed on a forum that hearing protection was recommended. I checked with the Radio Shack sound level meter and the level was 78 dBA. I looked for the permissible exposure times, first in the venerable Audio Cyclopedia (Tremaine) and then the more recent Handbook for Audio Engineers (Ballou), and to my surprise there was no mention of permissible noise exposure levels in either. Apparently it was not deemed important. On the web I quickly found my answer: indefinite exposure at that level. I copied the chart and taped it on the back of the RS meter. For the record: 90 dBA--8 hours, 100 dBA--2 hours, 110 dBA (discotheque level)--1/2 hour, 115 dB 1/4 hour or less.

Both old and new Radio Shack meters are reviewed by Daisuke Koya in Audio Xpress (6/07). Surprisingly he finds that the new meters, especially the digital one, have a huge high frequency peak at 8 kHz which is far out of spec'. The new Digital Display Sound Level Meter (33-2205) has a peak of 17 dB! Apparently he didn't contact the manufacturer about this. The new units roll off more in the bass than the old ones. The absolute sound level calibration was within 1 dB for all units. So if you want to make fairly accurate frequency response measurements, look elsewhere (or buy a used RS meter).

President, Boston Audio Society

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updated 8/12/07