how to figure what db level you listen at???

Discussion in 'Archived Threads 2001-2004' started by JohnMM, Mar 11, 2002.

  1. JohnMM

    JohnMM Stunt Coordinator

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    I often see posters saying that they listen at "nn" db's when they watch DVD's. How can I figure that out?

    Using AVIA and a RS SPL meter, I have already calibrated each of my speakers to 85 db. When I did this my "master volume knob" on the receiver was at -6. But when I watch a DVD, I am comfortable when the "master volume knob" is at -15.

    So how do I figure what db level -15 is? I can go back into AVIA and see how many db's my right front speaker puts out at when the "master volume knob" is at -15. But would that be accurate? Wouldn't the cumulative total from all the speakers be higher than just the one speaker?

    thanks.
     
  2. David_Stein

    David_Stein Second Unit

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    is it even correct to say you listen to DVDs at a certain dB level? i mean the volume changes all the time depending on whats going on in a scene...
     
  3. Vince Maskeeper

    Vince Maskeeper Producer

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    John,

    Usually when people post about this, they are using improper audio concepts (despite my infinite attempts to educate people). I cannot count the times I have had to explain that the 75db or 85db numbers have only to do with the specific test tones on VE/Avia-- and are not a total or overall SPL figure for program material.

    For example, people often say "I listen at 75db"- which means exactly squat. In actuality, they probably mean they listen to their system at a level calibrated with VideoEssential's tones set to 75db. In reality, in a system calibrated to ref level with AVIA or VE, the max peaks are in excess of 105db of total spl!!

    For accuracy, people should be comparing their listening levels vs. a set point, for example REFERENCE level. They should say "I listen at REF", or "I listen at 10 below ref"-- that would provide more accurate figures and more relative info for others to compare.

    In your case, ref level is the level you calibrated AVIA's tones to (-6 on your knob). If your volume knob is linear, then you can say you listen about 10db below ref. If you want to be sure- pop in avia and measure their tones at the -15 position on your knob- what level do you get? However many steps below 85, that's how many you are below ref (so if the Avia tone measures 74 with your volume at -15, you could say "I'm 11 below ref").

    If you're looking to say "I listen at 103db"- that is a more tough measurement to get. And you're right, the coupling of the various speakers will increase SPL level- and various soundtracks do/do not exploit the maximum available level. Also, the RS meter, depending on the weight setting, might give you inaccurate readings of total SPL during program material.

    But I don't think that measuring total SPL matters too much- most people quoting a total SPL level are way off the mark anyway. Anyone who really understands these concepts will simply provide a ballpark figure of how far below/above ref level they listen.

    -V
     
  4. JohnMM

    JohnMM Stunt Coordinator

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    Vince, thank you very much for taking the time to clear that up and educate me.

    Your explanation made a few other things click into place for me too.

    Thanks again.
     

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