Is my sound level meter busted?

[JDawg]

I bought a Radio Shack sound level meter from ebay and I don't think its working properly. When I move the dial to lets say 70 the meter moves all the way to the right. If I shake it a little the needle goes all the way back to the left at the -10 reading. So I play some test tones and the needle moves up to -2 so I assume this means its at 68dB? So I calibrate each channel so that the needle is at the same level but i'm still not sure if my meter is working properly. I thought the needle goes to the middle at zero and goes either left or right and you add or subtract the reading to what you have your scale at.

 

[MDS]

I thought the needle goes to the middle at zero and goes either left or right and you add or subtract the reading to what you have your scale at.

That is correct. If you have the dial at 70 and the SPL is actually over 80 dB the meter would peg to the right; likewise if it were 60 dB or under it would peg to the left. If either of those situations occur you need to move the dial to the next higher or lower number.

If you are using it for level calibration, use C weighting and Slow response. If you want to measure absolute SPL use A weighting and Fast response.

P.S. - JDawg? The skater that posts on RinkSkate? Probably not but it's a unique username.

 

[JDawg]

I have it set at c weighting and the response at slow as shown in the Avia calibration dvd. Since the needle doesn't start at the zero mark and always starts from the left at the -10 mark i'm going assume the guy on ebay sold me a broken meter. Plus the meter seems finicky because the needle sometimes moves all the way to the right for no reason when there's no sound. I'm gonna contact this guy and see what he says about this.

The name JDawg was actually a nickname that my coworkers started calling me by a few years ago. The name kinda stuck with me so thats why i'm using it.

 

[mtrycrafts]

Since the needle doesn't start at the zero mark and always starts from the left at the -10 mark i'm going assume the guy on ebay sold me a broken meter.

Not a good assumption. When there is no sound in the room, the meter will be on the left side of the meter, -10, no matter what the dial is. You need sufficient continuous sound level to move the meter.

Plus the meter seems finicky because the needle sometimes moves all the way to the right for no reason when there's no sound.

That doesn't sound right, of course, but then, it wouldn't need much to peg it, depending on the scale the dial is on.

 

[Dolby CP-200]

Take the battery cover off then remove the two screws holding the casing together then easy the casing apart.

Your then see the pc circuitry board something like this, depending on the type of model your Radio Shack SPL db metre is. If you can see the small dial that switches between on/off batt test and the various SPL readings if it appears to be lose just take a small screwdriver and tighten it up place the battery in the back switch it on and see if the needle responds without the hassle you where getting before.

 

[mtrycrafts]

What a sport You just jump right in there with pictures how to do it
I will remember this when I have a question, I know whom to contact

 

[Seth=L]

I like the first picture. This is a meter and a small screwdriver, move to next step.

 

[JDawg]

Dolby CP-200 - Thanks for the pictures and instructions on how to open it. I tightened the screw but i'm not sure if it worked yet. So far I haven't had any problems but i'm going to try it again tonight and see how it goes.

 

[Nick250]

You can always go to Radio Shack and buy a new one to see if reacts like the eBay one. I am reasonable certain RS has liberal return privileges, but confirm that first. Ah, I see you live in Canada, do they have Radio Shack's up there?

Nici

 

[Dolby CP-200]

JDawg

This SPL db meter is quite a few years old now and it’s fell onto the floor countless times due to the balancing act on the tripod, and it still keeps on running.

Check it battery test! If the needle is over to where it suppose to be to the right-hand side, and via shaking the meter in your hand if the needle remains over to the right-hand side it’s ok.

If for some reason when you do switch though the SPL db weightings and via producing a tone from your mouth like a humming low tone, or by hissing to see if the SPL db meter is responsive to sound pressure levels!

No the worse case and easy solution, if the microphone appears to be loss on the PCB circuitry board, you’ll need a very low wattage soldering iron to secure it has it may have just come loss over the time.

 

[JDawg]

We used to have Radio Shack in Canada but not anymore. Its now called The Source and they don't have the Radio Shack SPL meter so I had to go on Ebay to get one.

I checked the battery and it was still good but I charged it anyways. I haven't had anymore problems with the needle so i'm not sure if it was the battery or tightening the dial that fixed it. As long as it stays like this i'm happy.