Why calibrate to Reference Level?

Discussion in 'Archived Threads 2001-2004' started by Mike Sloan, Sep 23, 2002.

  1. Mike Sloan

    Mike Sloan Second Unit

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    I need enlightening. I hear all this discussion about reference level and running 3db hot,etc....? Before I run out and get the Video Essentials DVD and Radio shack meter..(which I am going to do)what am I missing by just matching all the speaker levels up by ear and blending in the sub until it sounds good? I have pre-set the sub level for music and find that I increase it a little for movies. Say for LOTR I find that -15 on my Denon 5803 is about as loud as I can take comfortably...and I crank up the bass to -5 on the Sub channel.I guess I need Bass for Dummies!

    Mike Sloan
    Have a VTF-3 and soon to purchase the dual Ultra package...so I need to get on board here...please help!:b
     
  2. John Garcia

    John Garcia Executive Producer

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    The tones are given for a defined dB level, thus the level of 75dB or 85dB.

    I tweaked my system somewhat by ear, but I have a strange room layout and a large room, and when I picked up the SPL meter, 3 of the 5 speakers needed additional tweaking to bring them to the same level.

    I have one setting for my sub - ref calibrated. I only change it for movies vs music once in a while.
     
  3. ThomasL

    ThomasL Supporting Actor

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    Mike, the most important thing is to balance your speakers from your sitting position. You'd be surprised how off your ears can be when compared to a set of test tones and a SPL meter. I used Avia and calibrated at 60db. I also turned it up and down and noticed that my receiver tracked with the increase. i.e. when I turned up the volume 5dbs, the SPL meter verified that I had gone up 5dbs. Before I balanced my speakers, I often had a hard time hearing dialogue from the center channel. Once balanced, I never had this problem again.

    cheers,


    --tom
     
  4. Matt Lopp

    Matt Lopp Extra

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    That's actually a great question. I haven't read the reasons for calibrating to reference level, but I'm sure there's a lot of truth to them.

    [muse=ON]

    For example, one reason is probably that DVD's, etc. are mastered at reference level volumes. Thus, to hear and calibrate a system as it was intended, it should be calibrated to reference level.

    However, I would volunteer that if you do calibrate to reference level, and listen at a different level, your system must be tweaked at the level you will listen at.

    In particular, according to the Fletcher-Munson curve, for human hearing, different frequencies are emphasized depending on volume level. For example, louder levels emphasize low and high frequencies in human hearing. This is one reason for the existence of the "loudness" button on receivers. The button can be engaged to make up for reduced lows and highs at lower volume levels.

    Thus, a system should be tweaked after calibrating at reference levels if the system is going to be used at lower volume levels. For example, a sub level can be increased to make up for reduced bass at lower volume levels.

    [muse=OFF]
     
  5. Bill Kane

    Bill Kane Screenwriter

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    Why reference? HTF EXPLAINER
    Since these DVD-based DolbyDigital 5.1 test disks hit the market in the '90s, coupled with the ever-available low-cost RadioShack meter, the home theater community has been given the opportunity standardize.
    Amplifier makers still offer their own variety of internal test tones. The most sophisticated, and I've only seen this in the past year and a half, provide external microphones and an amp sensor that automatically balances your speaker levels.
    If I say I calibrate with Avia to 85dB reference and actually play back when my amp volume reads -15dB under reference, that means the same thing to another user who used this same standard.
    If Matt, above, uses his sliding scale -- calibrate at the actual listening volume -- that only means something to him, not others because now his system is set at a unique or different spot.
    There are no "Reference Police" anyway, so people are free to adjust and enjoy their systems as they prefer. It's just that some like being on the same page as others so they can talk the same language.
    bill
     
  6. Matt Lopp

    Matt Lopp Extra

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    Good link and points Bill.

    Just to clarify. I didn't mean to advocate calibrating at listening volume. I intended to advocate calibrating at reference levels (or as instructed by your calibration tool: 75dB for VE and 85dB for AVIA) and THEN tweaking at actual listening levels.


    Regards,
    Matt
     
  7. James Zos

    James Zos Supporting Actor

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    I don't follow, Matt. If you calibrate to ref. standards, what then is left to tweak, I mean in terms of setting channel volume levels?
     
  8. Jack Gilvey

    Jack Gilvey Producer

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  9. Matt Lopp

    Matt Lopp Extra

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