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What Calibration data do you use for the Radio Shack SPL meter??

Discussion in 'Archived Threads 2001-2004' started by Anthony_Gomez, Aug 5, 2002.

  1. As mentioned earler, I am writing a nice little program for you guys, and I am going to do a fitting on 1/6 and 1/12 octave analysis.
    BUT!..I need to know what Calibration data most of you people use.
    I assume most of you use http://members.tripod.com/~terrycthe...um/page11.html
    ..but that is only 1/3 octave. Anyone have anything better?
     
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    That site didn't work.

    Well I forgot where I got this from but I use these correction values C weighted Slow response for test tones

    10Hz add 20
    12.5Hz add 16.5
    16Hz add 11.5
    20Hz add 7.5
    25Hz add 5
    31.5Hz add 3
    40Hz add 2.5
    50Hz add 1.5
    63Hz add 1.5
    80Hz add 1.5
    100Hz add 2
    125Hz add .5
    160Hz add -.5
    200Hz add -.5
    250Hz add +.5
    315Hz add -.5
    400Hz add 0
    500Hz add -.5
    630Hz add 0
    800Hz add 0
    1kHz add 0
    1.25kHz add 0
    1.6kHz add -.5
    2kHz add -1.5
    2.5kHz add -1.5
    3.15kHz add -1.5
    4kHz add -2
    5kHz add -2
    6.3kHz add -2
    8kHz add -2
    10kHz add -1
    12.5kHz add +.5
    16kHz add 0
    20kHz add +1
     
  3. That is the same file=)

    Thanks for confirming what I had thought.
     
  4. Patrick Sun

    Patrick Sun Studio Mogul

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    Just wanted to add that there's a hump in the 4K-8K range (I tend to subtract 3db-4dB for 5K, 6.4K, 1dB for 8K, add 5dB for 10K, and then it gets wooly over 10K), and large sloping decline in the 8K-20K range for the RS SPL meter. I would not use any of the listed correction factors above 4KHz.
     
  5. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    Anthony

    The SPL Meter is an invaluable tool, but I think is misused as a frequency response tool. The calibration files are taken as good, without any further research, just on a believe that "someone" has done it right.

    I prefer to stay with the readings of the SPLM and only take in to account their rated response, from 30 to 10,000Hz at +/-3 dB.

    As Patrick mentions, I have seen the hump too, and I guess the bass frequency response rolls off at a lower speed than the "correction" file allow us to think, but this is only a guess.

    I have a calibrated mic on order, and as soon as it arrives I will start to make tests with it comparing it to my SPLM. If you are still interested. contact me in a month or so.
     
  6. I am only doing this in the 10-100hz range for subwoofer duity.

    You will have the option of using Radioshace calibration data, your own calibration data, and no calibration data.
     

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