RS SPL meter calibration

Discussion in 'Archived Threads 2001-2004' started by Thomas F, Mar 22, 2002.

  1. Thomas F

    Thomas F Stunt Coordinator

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    I noticed a calibration adjustment port on the side of my Radio Shack SPL meter, and I was wondering how I can tell if my meter is properly calibrated. It's an old meter and I would like to check the calibration and re-calibrate if necessary. Has anyone done this?
     
  2. Harry Lincoln

    Harry Lincoln Stunt Coordinator

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    Quote from RS owners manual:

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    >The sound level meter has benn accurately calibrated at our factory, and normally will not require further adjustment. Special equipment , including a sound generator, is required for calibration. The hole provides access, however, unless you are qualified, we suggest such adjustments be left to your Radio Shack service technician.

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    Thomas, even if the meter was out, lets say it was giving a reading that was 3db too high, it would be the same for all channels. So it would still be fine for balancing the channels on your HT. If you were trying to set your system to reference levels you might end up a few dbs above or below.

    If your still concerned about it, maybe you can compare your RS meter to a newer one - if you know someone who has one. This should give you a rough idea of how accurate it is.

    Harry.
     
  3. Stephen Houdek

    Stephen Houdek Second Unit

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    I read a review somewhere, can't remember where or I'd post a link.....However, the RS meters are supposed to be VERY well calibrated from the factory. In fact, the review I read stated the reviewer's meter was taken the the THX labs for calibration and it was dead on.

    Doubt you have anything to worry about.
     
  4. Rob Warren

    Rob Warren Auditioning

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    In answer to your question, is yes you can calibrate with the right tool. It's a piston that you stick on the mic end of the SPL meter and it creates noise at 124 dB. I calibrated my RS meter and it was within less than a 1/2 of a dB. I don't think you would want to spend approx. $8000.00 for this tool. I wouldn't worry about calibration unless I was tuning professional environments, and getting paid well for it.
     
  5. Rick Guynn

    Rick Guynn Second Unit

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    Rob, was that generator at a set frequency? I have read many posts around here about 'correction factors' for RS meter once you get outside of a certain frequency range. I would love to see some more numbers from someone with the equipment to do an analysis.

    Rick
     
  6. Rob Warren

    Rob Warren Auditioning

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    I got some info from a friend. This tool is called a Piston phone, made by B&K. It apparantly puts out some type of warble tone, but it is a little more than just a sound. It registers 124 dB spl flat or "C" weighting. The cost is probably around $800.00, a far throw from me thinking 10 times more than that. hehe The microphone mouth is about 1/2" wide and it happens to fit an RS spl meter perfectly. [​IMG]
    I must say, I certainly wouldn't bother with calibrating really unless I was a contractor needing it for my business.
    [​IMG]
     

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