sound meter

[Gray E Fowler]

The radio shack meters are only +/- 3db, but usually perform better, and 
that is double the volume. The good meters ($250) are +/- 1 or 1.5 db. 



Gray Fowler
Principal Chemical Engineer
Composites Engineering




"Tony Stillman" <tony at radiosouthrc.com>
Sent by: discussion-request at nsrca.org
04/26/2004 10:52 AM
Please respond to discussion

 
        To:     <discussion at nsrca.org>
        cc: 
        Subject:        Re: sound meter


Brian:

Do you realize that 3 DB is DOUBLE the sound level?  That's not even
close.....

Tony Stillman
Radio South
3702 N. Pace Blvd.
Pensacola, FL 32505
1-800-962-7802
www.radiosouthrc.com
----- Original Message ----- 
From: "Brian Young" <b4598070 at yahoo.com>
To: <discussion at nsrca.org>
Sent: Monday, April 26, 2004 8:34 AM
Subject: Re: sound meter


> 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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>
>
>
>
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