Sound Level Meter

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ricky1

Member

Jan 18, 2000

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• Feb 20, 2002

• #1

For anyone interested, you can buy a Digital Sound Level Meter at Radio Shack (PN 33-2055) for $60. Although it does not meet ANSI Standard S1.4, it claims an accuracy of +-2dB. I bought one yesterday, but have not tried it yet. It appears to be VERY trick. http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F002%5F003%5F018%5F000&product%5Fid=33%2D2055

 

fremontguy

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Jul 1, 2000

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• Feb 21, 2002

• #2

Good tool to have out here, can I borrow yours?:)

 

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ricky1

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Jan 18, 2000

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• Feb 21, 2002

• Thread starter
• #3

Sure, Les, come on over;)

 

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zsr

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Mar 17, 2001

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• Feb 23, 2002

• #4

+-2db isn't that wildly inaccurate? +3db is an increase of 100% !!!!

 

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ricky1

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Jan 18, 2000

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• Feb 23, 2002

• Thread starter
• #5

zsr

I certainly understand your point, but even the $600 model is +- 1.5dB. Also, at a legal level of 101dB isn't +- 2dB like 2% ?

 

K

KTA

Member

Jul 14, 2000

287

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• Feb 23, 2002

• #6

yeah.... +-2db is pretty accurate... and for only $60 it sounds like a good deal

 

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zsr

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Mar 17, 2001

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• Feb 23, 2002

• #7

Re: zsr

Originally posted by ricky1
I certainly understand your point, but even the $600 model is +- 1.5dB. Also, at a legal level of 101dB isn't +- 2dB like 2% ?

Click to expand...

No Rick, Every increase of 3db is an increase of 100%

E.g. 90db is twice as loud as 87db, which is twice as loud as 84db.

Odd I know, but thats how it works..... so +- 2db is a bit of a waste of time, like having a tyre pressure guage thats +- 10psi !!!!

 

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spodeinator

Member

Jun 27, 2001

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• Feb 23, 2002

• #8

Originally posted by zsr


No Rick, Every increase of 3db is an increase of 100%

E.g. 90db is twice as loud as 87db, which is twice as loud as 84db.

Odd I know, but thats how it works..... so +- 2db is a bit of a waste of time, like having a tyre pressure guage thats +- 10psi !!!!

Click to expand...

You must be thinking of those Metric decibels :)

spode.

 

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zsr

Member

Mar 17, 2001

90

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• Feb 23, 2002

• #9

Fom Britannica

"...(dB), unit for expressing the ratio between two amounts of electric or acoustic power or for measuring the relative loudness of sounds. One decibel (0.1 bel) equals 10 times the common logarithm of the power ratio—i.e., doubling the intensity of a sound means an increase of a little more than three dB. …"

 

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BRush

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• Feb 23, 2002

• #10

Re: Re: zsr

Originally posted by zsr
E.g. 90db is twice as loud as 87db, which is twice as loud as 84db.

Click to expand...

Well, maybe not. "Loudness" is not the same as sonic power or intensity, which is what the db scale represents. So 90db has twice the intensity as 87db, but that does not necessarily mean that it's twice as loud, since "loudness" is more subjective. The rule of thumb seems to be that every ten decibel increase will seem to an "average" listener to be about twice as loud - but that also can depend on the pitch of the sound.

 

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zsr

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Mar 17, 2001

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• Feb 24, 2002

• #11

Re: Re: Re: zsr

Originally posted by BRush


but that also can depend on the pitch of the sound.

Click to expand...

well that bit at least is correct. But remember we are not comparing an open V8 to a neighbours Hi Fi, but a bike engine to a (the same?) bike engine.

 

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BRush

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• Feb 24, 2002

• #12

Re: Re: Re: Re: zsr

Originally posted by zsr
But remember we are not comparing an open V8 to a neighbours Hi Fi, but a bike engine to a (the same?) bike engine.

Click to expand...

I agree completely. I was merely pointing out that Your statement to ricky1 that "90db is twice as loud as 87db" is not really correct. Loudness and intensity are related but not the same, since loudness contains a large subjective component. Britannica had it right. If you had said that 90db represents twice the intensity as 87db - that would have been more accurate.

 

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RetSenior

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Dec 15, 2000

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• Feb 25, 2002

• #13

If the meter is only off by 2dB's then it's not a waste of my time. If it gets to be off by about 6dB's then it would.

 

Jeff Gilbert

N. Texas SP

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• Feb 27, 2002

• #14

An increase of 3db is a noticeable difference. I have one of those Radio Shack meters too and I seldom use it, not because it isn't accurate but because it's not practical. A 4khz frequency at 90db to me is a lot more irritating than an 80hz frequency at 100db.

Higher frequencies travel faster than lower frequencies but they fade out quicker, especially on a humid day. Go figure:eek:

 

Last edited: Feb 27, 2002

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NVR FNSH

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Oct 31, 2000

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• Feb 27, 2002

• #15

Most people can't really discern a difference of 2dB. And yes, the freqs you are measuring make a huge difference. The small turbine generator I worked on previously passed the test/spec if you only measured out to 14kHz but failed miserably if you upped the range to 20kHz. I think those numbers are correct but I may be off a little bit. The spec was written with reciprocating engines in mind not turbines We met the letter of the law but not the spirit. Even then nobody thought the noise was objectionable, just different. Acoustics is almost like statistics - make the numbers say what you want them to. It doesn't matter if you exceed the limit if nobody complains:)

Brian