Sound Level meter requirements

[John Ferrell]

The best of the meters drift a little. When some one faces a recheck it has 
proven to be a good idea to validate the meter against a standard source. 
The one that AMA (also used at Pensacola Worlds) uses has a price tag of 
about $1500 and is available from Grainger's. It has been my experience that 
if you limit your noise to 2db less than the max with a Radio Shack meter 
you will be safe. It is easiest done with prop selection.

FWIW, I have never been able to distinguish 2db by ear in the 94db range.
John Ferrell
http://DixieNC.US

----- Original Message ----- 
From: "John Pavlick" <jpavlick at idseng.com>
To: "NSRCA Discussion" <discussion at nsrca.org>
Sent: Tuesday, February 15, 2005 1:20 AM
Subject: Sound Level meter requirements


> Does anybody know the requirements for a sound level meter capable of
> testing for AMA noise requirements? I've found a few that measure A and C
> weighted response. Some are IEC Type 2 compliant. Is this good enough for
> AMA standards? Also, there's no spec. for the measured frequency range
> requirement. All meters specify a range (i.e. 30Hz - 12KHz). What range 
> does
> an AMA approved measuring device have? There must be a list of 
> requirements
> somewhere, otherwise it's going to be a guessing game. It's not like 
> buying
> a tape measure.
> I've been thinking of getting one for several reasons. First, I want to
> test some of the planes at my club field to get an idea of how much noise
> the average sport model generates compared to a lawnmower or a weed 
> whacker.
> Second, I would like to include a noise measurement for the airplanes that 
> I
> write magazine reviews for. I think it would be a good idea for the 
> general
> public to see that most pattern planes are VERY QUIET - I don't think they
> realize this.
>
> John Pavlick
> http://www.idseng.com
>
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