[GreenKeys] Re: teletype machine noise levels

[Sam Hallas]

gil smith wrote:
> This twelve-year-old Radio Shack Sound Level Meter (model 33-2050) has 
> seen little use, and I do not know whether it is accurate in any way.  
> According to the manual, the dB readings are "referenced to 0.00002 
> microbar" (whatever a bar is), with an accuracy of +/- 2 dB.  Then they 
> say that "0 dB = 0.0002 microbar," a factor of ten different from the 
> previous paragraph.  So considering the source (radio-shlock), which I 
> consider to make junk stuff anyway, and the contradictions in the cheesy 
> little manual, I offer the following measurements for your amusement only.

Ha! Gil. I had the same sort of confusion a while ago when I had to take 
some sound level measurements at work. Sound engineers talk a whole 
different language and also have two different reference points for 
their dB measurements with a difference of 94 dB if I recall!

A bar is unit of pressure equal to 10^5 Pascal. Usually seen on weather 
charts as millibars. (eg 990 millibar = depression, 1030 millibar - 
anti-cyclone).

Cheers,
Sam