Just out of curiosity

Discussion in 'AV Receivers' started by WendyS, Apr 7, 2004.

  1. WendyS

    WendyS Stunt Coordinator

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    Reference levels.
    I read this all the time. What does it mean?
     
  2. MuneebM

    MuneebM Supporting Actor

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    Reference level is when you calibrate your speaker levels using, for example, Digital Video Essentials and an SPL meter, the volume and speaker levels at which each speaker reads 75 dB on the SPL meter when playing the test tone from the disc.

    As an example, the reference volume level of my speaker set-up and receiver is -2.0 dB on my receiver's dial. At this reference volume level, each of my speakers measure 75 dB on the SPL meter when playing their corresponding test tone if the speaker levels are set as such:
    Front Left: 0.0 dB
    Front Center: -2.0 dB
    Front Right: +1.0 dB
    Surround Right: +1.5 dB
    Surround Back: +3.5 dB
    Surround Left: +2.5 dB

    Furthermore, -2.0 dB being my reference volume level on my receiver is also the Dolby reference volume. When I play a movie at that volume it is friggin' loud, so I usually watch movies 10 dB less than reference, i.e. -12.0 dB on my receiver.
     
  3. Angelo.M

    Angelo.M Producer

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    Maybe, maybe not. Seventy-five dB is not universally agreed upon, as far as I've read. I think the THX standard uses 85 dB.

    And several folks at my Audiophiles Anonymous meetings swear up and down that reference level is 66 dB.

    [​IMG]
     
  4. MuneebM

    MuneebM Supporting Actor

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    Angelo.M, I was using the test tones on the DVE disc as an example. When those test tones are played and the SPL reads 75 dB, that's reference level. That's what I meant, sorry for the confusion.
     
  5. Howard_You

    Howard_You Stunt Coordinator

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    MuneebM, what is the max. volume setting on your RX-V2400? I'm a bit suprised that at the nearly -0dB setting the level is only 75dB, not that I don't think 75dB is loud but I would have expected closer to 90dB or so. Are those JBL speakers very inefficient?

    I recall reading in another thread that someone had the HK AVR630 and measured 100dB at a setting of -0dB, mind you they were using a piece of music in stereo mode not test tones in surround mode.
     
  6. Angelo.M

    Angelo.M Producer

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    MuneebM:

    No worries at all! [​IMG]

    I just wanted to clarify that "reference level" can mean different things.
     
  7. MuneebM

    MuneebM Supporting Actor

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    Howard, the test tones on DVE are recorded 30 dB lower than reference level (105 dB), so at my reference volume of -2.0 dB, they are supposed to measure 75 dB on the SPL meter. If the test tones were 85 dB, as on Avia, they would read 85 dB on the SPL meter at -2.0 db on my receiver, and so on. I'm sure if I had a 105 dB test tone playing, it would measure 105 dB on the SPL meter at -2.0 dB on my receiver.

    To answer your question, the max volume setting on the RX-V2400 is +8.5 (if I remember correctly), but that's 10.5 dB louder than reference and I would never watch a movie at that level, as it is much too loud, and there would probably be quite a bit of distortion.
     
  8. Aaron Gilbert

    Aaron Gilbert Second Unit

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    'Reference Level' can be achieved in several ways with varying kinds of equipment, but it all boils down to the same end result. The idea is that when you set your receiver or processor's volume control to a specified level, after you have calibrated the system, the output level you experience will be extremely close to what the movie producer (or whomever is in charge of such a thing) wanted in the commercial cinema. Thus, the sound level you would have experienced in the commercial movie theater is the reference, not taking into account varying levels between commercial theaters.

    Whether playing back movies in your home at the same level is desireable is an entirely different question, and completely a matter of personal taste. I find it varies greatly from one movie to the next. For movies without much action, reference level seems just fine to me, as dialogue is easiest to understand and you notice the surround ambience more. With blockbuster action movies though, such as The Matrix, Lord of the Rings, or Star Wars, I tend to find playback at reference level a bit too loud. In those cases, I am typically at -5 to -10dB under reference level. -10dB corresponds to a level that is perceived as half as loud.

    Aaron Gilbert
     
  9. Howard_You

    Howard_You Stunt Coordinator

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    MuneebM,

    Now I get it...thanks for the explaination.
     
  10. Fernando Saa

    Fernando Saa Stunt Coordinator

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    Hi, everyone. It's not my thread but it is interesting and informative. Here's my question:
    So, what about if your receiver auto-calibrates like my Yamaha 2400? what's the reference level there?. I have the Video Essentials DVD; should I recalibrate manually?. I long thought that reference level was the level they use in commercial theaters. If I take my spl meter to the theater, would it read 105db during maximum peaks? So much to learn...
     
  11. MuneebM

    MuneebM Supporting Actor

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    Fernando, when your RX-V2400 auto-calibrates the speaker levels via YPAO:
    (1) there's no way for you to know what your reference level volume is on the dial
    (2) the YPAO-calibrated speaker levels will not be as accurate as they can be with an SPL meter and calibration disc

    If you want, you can determine your reference level without a calibration disc, but an SPL meter is required. Just play the front left speaker test tone (with the "Test" button on the RX-V2400's remote), set up your SPL meter at the listening position at about a 60 degree angle, increase the volume on the RX-V2400 until you read 85 dB on the SPL meter. That will be your reference volume level, should be roughly the same as mine: around -2.0 dB on the dial. Of course, I still recommend you get a calibration disc (my recommendation is DVE for a 6.1/7.1 set up) and use that instead with an SPL meter.

    I've only used YPAO for speaker distances and speaker phase checks, and I plan to try out the parametric EQ some time in the near future, but I truly think my speaker levels set with DVE and my SPL meter are more accurate than those determined by the YPAO.
     
  12. ScottCHI

    ScottCHI Screenwriter

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    um, that is highly dependent upon numerous variables. doubtful his "reference volume" will be the same as yours, unless you know more about the rest of his system and ht room than i do.
     
  13. Shane Martin

    Shane Martin Producer

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    My reference level is -20 on my knob. That is mainly because of my efficient speakers(which are being sold).

    It's widely accepted that 75 db is the "reference" level. Some discs are louder than others but you compensate for that. I think Avia is 85db.
     
  14. ScottCHI

    ScottCHI Screenwriter

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    one of the most important variables is the speaker distance
     
  15. Angelo.M

    Angelo.M Producer

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    There are scores of folks who would strongly disagree.
     
  16. Wayne Ernst

    Wayne Ernst Cinematographer

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    Angelo, Is that a 12-step program?

    Step #1) We've realized that we were powerless over our audio buying habits.
    Step #2) We've made amends to all the local audio dealers that we've said bad things about.
    Step #3) ...

    [​IMG] [​IMG] [​IMG] [​IMG]
     
  17. Angelo.M

    Angelo.M Producer

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    Step #3: We've surrendered our Shakti Stones, Tice Clocks and Elephant Ears.

    Step #4: We've put away the green markers. For good...

    Step #5: We've donated our "Vinyl Rules!" t-shirts to the Salvation Army.

    [​IMG]
     
  18. Shane Martin

    Shane Martin Producer

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    There are scores of folks who think all amps sound the same. Oh well not my problem.

    But for instance, name those scores of people?
     
  19. MuneebM

    MuneebM Supporting Actor

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    Shane, this is a ridiculous statement. I really don't think your reference level is -20 on your knob because your speakers are extrememly efficient. There are many receivers out there that have a max volume of 0.0 dB on the dial, so the entire dial range is shifted. For example, my RX-V2400 has a max volume level of +11.5 dB and my reference volume is -2.0 dB. I used to have a cheap Kenwood receiver in the same room with the exact same speakers. The Kenwood had a max vol. level of 0.0 dB and its reference level was -12.0 dB, notice the shift. Are you saying the el-cheapo Kenwood receiver is more efficient than my $1K+ Yamaha? I highly doubt it! Furthermore, I've done quite a few SPL calibrations for friends, and one of my friends has a Yamaha RX-V540 with tiny Paradigm satellite speakers. His dial has a max vol. of 0.0 dB and his reference level is -14 dB on the dial, once again notice the shift as compared to -2.0 dB on my dial with a max vol. of +11.5 dB on my dial. Are his Paradigm satellite speakers that much more efficient than my JBL Studio Series that costed me twice as much? Once again, I really don't think so, because if that's the case I just should've bought those tiny Paradigm satellite speakers!
     
  20. Angelo.M

    Angelo.M Producer

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    [​IMG]

    Oh, come now. No need to be so serious.

    75 dB as reference is arbitrary, just as the 85 dB THX reference is arbitrary, just as 66 dB (recommended by many folks at AudioCircle and similar "audiophile" forums) is arbitrary.

    So, as far as names, you can include anyone who has calibrated their system to THX reference, for example. I'd bet there's at least one score of them. [​IMG]
     

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