SPL Meter & Me

Discussion in 'Archived Threads 2001-2004' started by Brian Johnson, Jan 6, 2002.

  1. Brian Johnson

    Brian Johnson Supporting Actor

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    Well, I finally went to RS and bought the SPL meter everyone says we MUST have....
    Anyways, let me tell you what I did and you can tell me if I need to do any more.
    Set the meter to c & slow. set it too 80 db and played my receivers test tones. Pretty much got all the speakers in the -5 range (which should put it at 75db correct?) My sub was up around 0 on the 80 db scale.
    Is this all I have to do, I dont have any test discs.
    Just a side note. Boy how my ears decieve me. I wasnt even close in setting those speakers before the spl meter, got to test it with "the fast & the furious" What an improvment. Dont know if was worth 40 bucks I spent, but I guess if i wanted to be mr. cheap-o I could take it back :p)
    EDIT: let me rephrase. It was well worth the 40 bucks [​IMG] but if I only get to use it once.......... i dont plan on changing much- YET.
     
  2. Kwang Suh

    Kwang Suh Supporting Actor

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    It's worth keeping. Everytime you adjust your system, you'll need to use it.
     
  3. Jeffrey Forner

    Jeffrey Forner Screenwriter

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    You'll be surprised with how often you may have to use that little device. Consider it an investment in home theater excellence.
     
  4. TanD

    TanD Stunt Coordinator

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    i used to set up by the receiver internal test tone(the denon 5800), but when i set it up by the Video Essential, every thing was off by -2db, and sub remain the same. So i am not exactly sure which give me the real correct test tone level, but i trust the VE than the receiver.
     
  5. Vin

    Vin Supporting Actor

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    Johnson, Tan makes a good point about the receiver's test tones being off....I also found this to be the case.
    If you have the Fight Club DVD you could use the Optimode section that's included on it to calibrate your speakers....I've tested it against Video Essentials and found it to be accurate.
     
  6. TedO

    TedO Stunt Coordinator

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    You mean I could rent the DVD Fight Club and use it to set my speaker level?

    TedO
     
  7. Andrew Beck

    Andrew Beck Stunt Coordinator

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    question, are the tones on the THX optimized dvd's supposed to be set at 75dB or 85db?
     
  8. Vin

    Vin Supporting Actor

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    The tones for Optimode (on Fight Club) have been recorded at 75dB, as noted in the Optimode section of that disc....my testing of the tones against those on the Video Essentials disc confirmed their accuracy.

    Vin
     
  9. Andrew Beck

    Andrew Beck Stunt Coordinator

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    Vin, I would imagine all THX discs would be the same. Anyone ever analyzed the tones in TPM?
     
  10. Vin

    Vin Supporting Actor

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  11. ColinM

    ColinM Cinematographer

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    In TPM I had sub readings - 10db for some reason. All of the other channels seemed varied, as well.
    I see the comment "Not for Calibration" in every optimode I've seen, but I haven't seen Fight Club or Castaway at home yet, so...
    I have VE. Nuff said.
    Good Luck, everyone
    [​IMG]
     
  12. ColinM

    ColinM Cinematographer

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    Maybe there's different THX Optimode versions out there...
     
  13. Charles L.

    Charles L. Agent

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    Tan D.

    I've had similar results with my 5700 test tones and VE. I used a third test ( sine waves with the recording values attached) and VE was wrong.
     
  14. TanD

    TanD Stunt Coordinator

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    Now you are telling me a test disk create by professional for system calibrate purpose is wrong! then i don't know what to trust anymore, receiver's test tone? VE? what else should i trust?
     
  15. Brian Bunge

    Brian Bunge Producer

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  16. ColinM

    ColinM Cinematographer

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    Charles L. -

    How wrong was it? Got Numbers?
     
  17. Vin

    Vin Supporting Actor

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    Brian, very interesting article, thanks....it seems to verify what I've found using Fight Club's Optimode tones, i.e., that particular disc is indeed a valid source of calibration tones.
    From the article>"Unfortunately, with 'Fight Club' being the only exception, the THX Optimode calibration noise has been recorded at -20dBFS (twenty decibels below full-scale) which results in an SPL output of 85dB, 10dB above what the on-screen graphics state should be the case".
     
  18. Brian Bunge

    Brian Bunge Producer

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    Vin,
    You're very welcome. I've been meaning to post this for quite some time. After all, the initial article is about 2 years old. I've just been waiting for the issue to arise again!
    BTW, Stuart M. Robinson is a very knowledgeabe person on such subjects. His forums (www.smr-forums.com) were the first HT forums that I found. Even though they don't have nearly the traffic as this one, quality information is plentiful and there is absolutely NO bickering or name calling over there. Everyone is treated with the same respect that they require themselves. Stuart is also able to debunk a lot of the myths in the audio world because of his first hand knowledge of the business itself as well as the entire encoding/decoding process.
    Again, glad I could help!
    Brian
     
  19. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    I am failing to see the problem with a test tones calibration tone to be the incorrect loudness. If all of your speakers are balanced together, then what is the problem? Can someone explain this to me?
     

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