Reference levels

Discussion in 'AV Receivers' started by CalvinCarr, Jan 9, 2004.

  1. CalvinCarr

    CalvinCarr Supporting Actor

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    I keep hearing this term. What does it mean?
     
  2. Andrew Pezzo

    Andrew Pezzo Second Unit

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    I have seen it described as a setting for calibrating speakers so when you talk to someone about listening levels you can express it in terms if decibels. I could be way off but I am in the ballpark.
     
  3. Jerome Grate

    Jerome Grate Cinematographer

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    Reference levels refer to a range of volume where the listener listens to music or a movie at that volume level for peak performance. Depending on what reciever you have that can be around 20 to 25 dbs or 3/4 less peak volume. I also believe that the range is less the distortion than higher volumes.
     
  4. John_V

    John_V Agent

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    On the AVIA disc, they describe reference levels as how movie theaters calibrate their sound system. They play a test signal (pink noise), so that it is at 85 dB. This is the "reference level". The loudest (peak) levels of the movie soundtrack end up being 20 dB higher than that, 105 dB.

    If you try to calibrate your home theater the same way, you'll find it's LOUD. That's way you'll hear some people say they've got their volume set to -10 dB below reference, that puts the peaks around 95 dB.

    In my theater, I've got the peaks around 91dB.
     
  5. Robert Hoffman

    Robert Hoffman Stunt Coordinator

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    Why is it with Avia that you set all speakers to play the pink noise at 85db, but then when you match the subwoofer it suggests using 70db? Does it really matter what level you match the sub at as long as it matches?
     
  6. jeff peterson

    jeff peterson Supporting Actor

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    It wants the sub to be set 15db less than the speakers. To answer your question, no, as long as you set the sub 15 less than the speakers.
     
  7. John_V

    John_V Agent

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    I think setting the sub 15dB less than the rest of the speakers is incorrect. This would result in a sub level that is much too quiet.

    Refer to the calibration help section on the SVS website. They say:

    "As the tones start, alternating, speaker to speaker (watching your sound meter now) set each speaker’s volume to 75 dB, using the receiver’s channel controls....What to set the sub to? You might find that a higher level, relative to your main speakers is preferable. In other words, set to a bit higher than 75dB..."
     
  8. Robert Hoffman

    Robert Hoffman Stunt Coordinator

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    Yeah...with Avia, you calibrate the mains & surrounds at 85 dbs. But when you calibrate the sub, you turn down the master volume of the mains so they output at 70db with the test tone, and then match the sub at 70db. Just thought it was strange the sub wasn't also calibrated at 85db. Maybe they don't want you to piss off the neighbors with the rumbling test tone at 85dbs [​IMG]
     
  9. jeff peterson

    jeff peterson Supporting Actor

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    I'm not sure that's right, Robert. You're then matching the sub's level to the speakers. It's the same as doing all at 85db. I think what they want you to do is lower the SUB's volume so that it's at 70 when the speakers are at 85. In other words, calibrate the mains/surrounds at 85, DON'T turn down the master volume, but turn down the SUB'S volume to be 70.
     
  10. Robert Hoffman

    Robert Hoffman Stunt Coordinator

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    My memory could be incorrect, but I'm pretty sure the instructions as it plays the sub & main test tones (it alternates back & forth) says to set the SPL meter so that both are matched. It then references a 70db level for carrying out the test. I know that the manual for my SVS says that you might want to set your sub ~3db above the mains (which I did). Setting the sub 15db below would be too quiet.
     
  11. John_V

    John_V Agent

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    I'm 99.99% sure Robert's right. To learn more about this, check out this article fromt the creator of AVIA. He mentions that the goal of calibration is to get the sub to output at the same SPL (sound pressure level) as the main speakers.

    http://www.svsubwoofers.com/faq_avia.htm
     

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