looking for the correction table for the Radio Shack SPL meter...

Discussion in 'Archived Threads 2001-2004' started by John Doran, Feb 6, 2003.

  1. John Doran

    John Doran Screenwriter

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    does anyone know if the DIGITAL SPL meter from radio shack suffers from the same low-frequency inaccuracy as the analog one?

    and, if so, does anyone have the complete correction table?

    thanks,

    - jd
     
  2. Lynn Little

    Lynn Little Stunt Coordinator

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    Yes it does. Here's the correction table:

    10hz.....+20db
    12.5hz...+16.5db
    16hz.....+11.5db
    20hz.....+7.5db
    25hz.....+5db
    31.5hz...+3db
    40hz.....+2.5db
    50hz.....+1.5db
    63hz.....+1.5db
    80hz.....+1.5db
    100hz....+2db
    125hz....+.5db
    160hz....-.5db
    200hz....-.5db
    250hz....+.5db
    315hz....-.5db
    400hz....0db
    500hz....-.5db
    630hz....0db
    800hz....0db
    1k.......0db
    1.25k....0db
    1.6k.....-.5db
    2k.......-1.5db
    2.5k.....-1.5db
    3.15k....-1.5db
    4k.......-2db
    5k.......-2db
    6.3k.....-2db
    8k.......-2db
    10k......-1db
    12.5k....+.5db
    16k......0db
    20k......+1db
     
  3. John Doran

    John Doran Screenwriter

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    Lynn,

    thatnks a lot.

    would you happen to know what the corrections are for the intervening frequencies? i'm specifically looking for them from 10hz-100hz at 1hz increments.

    do you know where i might be able to find them?

    thanks again for the help - i really appreciate it.

    - jd
     
  4. Lynn Little

    Lynn Little Stunt Coordinator

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    "i'm specifically looking for them from 10hz-100hz at 1hz increments."

    Wow! I don't know where you could find a correction chart with such minute increments. Sorry...
     
  5. Seth_L

    Seth_L Screenwriter

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  6. John Doran

    John Doran Screenwriter

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  7. Jeremy Stockwell

    Jeremy Stockwell Supporting Actor

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    Here's the interpolated values I used for 10-80 Hz.

    JKS

    1020
    1118.25
    1216.5
    1315.25
    1414
    1512.75
    1611.5
    1710.5
    189.5
    198.5
    207.5
    217
    226.5
    236
    245.5
    255
    264.66
    274.33
    284
    293.66
    303.33
    313
    323
    333
    343
    353
    363
    372.5
    382.5
    392.5
    402.5
    412.5
    422.5
    432.5
    442.5
    452
    462
    472
    482
    491.5
    501.5
    511.5
    521.5
    531.5
    541.5
    551.5
    561.5
    571.5
    581.5
    591.5
    601.5
    611.5
    621.5
    631.5
    641.5
    651.5
    661.5
    671.5
    681.5
    691.5
    701.5
    711.5
    721.5
    731.5
    741.5
    751.5
    761.5
    771.5
    781.5
    791.5
    801.5
     
  8. John Doran

    John Doran Screenwriter

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    thanks a lot jeremy - i appreciate your taking the time.

    - jd
     
  9. Edward J M

    Edward J M Cinematographer

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    John, there is a fix for the RS meter, if you are willing to buy some capacitors and break out the soldering iron. I don't have it here at work, but it is saved on my home PC. It doesn't look too hard, and the instructions are detailed. If I owned one, I'd certainly perform the mods.

    After the mods, the meter is supposedly accurate to well below 20 Hz. One easy way to tell, run a before/after FR sweep under identical conditions and compare the results.

    Send me PM if interested.

    Regards,

    Ed
     
  10. BradJudy

    BradJudy Stunt Coordinator

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    I believe these are the modifications that Edward is referring to.

    I also recently purchased one of these meters and I'm a bit concerned that the multiple correction tables I have found don't all agree. I'm planning on importing one into Speaker Workshop and playing around with it.

    I am considering the mods I linked to, but have not performed them, nor do I know what an appropriate correction curve would be for a post-mod meter.
     

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