sound meter

[Brian Young]

Do they calibrate the meter at the NATS?

I think the RS meters are within spec if they are +/-
3DB. 


--- "ed.schummer" <ed.schummer at sbcglobal.net> wrote:
> Couldn't agree more.  Most of these meters work
> pretty well when measuring
> relative levels of pink noise, such as in
> calibrating control room levels to
> a SMPTE standard, or such.  The problem comes up
> when there is a dominant
> frequency that is much louder than the others, as
> often occurs with our
> planes.  We once tested a bunch of these meters, and
> although on average
> they were pretty good, I have seen as much as 6 dB
> difference from one meter
> to another at single frequencies, both meters
> calibrated to the same level
> with pink noise....
> 
> Ed
> 
> 
> ----- Original Message ----- 
> From: "Ed White" <edvwhite at yahoo.com>
> To: <discussion at nsrca.org>
> Sent: Sunday, April 25, 2004 5:22 AM
> Subject: Re: sound meter
> 
> 
> > At work I have access to a large acoustics test
> lab
> > and borrowed a portable calibrator.  My RS sound
> meter
> > was off up to + AND - 3 dB.  It varied
> considerably
> > with frequency.  At lower frequencies (<1 KHz) it
> read
> > low by 2-3 dB, at higher frequencies (>1 KHz) it
> read
> > high by 2-3 dB.  Pretty much varied all over the
> > place.
> >
> > The message is don't get hung up on 95 dB vs. 96
> dB.
> > The RS meter will give you a ballpark absolute
> value,
> > and as Earl said will give you decent relative
> > measurements.
> >
> > Ed
> >
> > --- "Del K. Rykert" <drykert at localnet.com> wrote:
> > > My radio shack soundmeter was off by almost 3 dB
> > > when it was calibrated.
> > >
> > >         Del
> > >   ----- Original Message ----- 
> > >   From: Earl Haury
> > >   To: discussion at nsrca.org
> > >   Sent: Saturday, April 24, 2004 9:05 AM
> > >   Subject: Re: sound meter
> > >
> > >
> > >   Steve
> > >
> > >   It matters a lot. The rules specify dB-A, so
> use
> > > the A scale. Without a calibrator most sound
> meters,
> > > even the expensive variety, are really only good
> for
> > > comparative measurements. So - use it to find
> what
> > > makes the airplane quieter but don't get fixated
> on
> > > the absolute number without a calibrated
> reference.
> > >
> > >   Earl
> >
> >
> >
> >
> >
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