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
email me HERE