Basic Calibration Question

Discussion in 'Archived Threads 2001-2004' started by EricHaas, Mar 23, 2002.

  1. EricHaas

    EricHaas Supporting Actor

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    I just got the Avia disk and rat shack analog SPL meter. I went through the first setting of test tones and balanced my 5 main speakers. Then I went on to subwoofer calibration. With the speakers set to small, the subwoofer obviously puts out dramatically more SPL. My issue is that when they are set to small, I CANNOT calibrate the sub to the other speakers - even turning the sub level down to -10 won't balance it properly. Am I supposed to calibrate with all the speakers set to large so that I am calibrating only the LFE channel against the remaining speakers? Then can I just set it back to small when the calibration is over?
     
  2. Keith Mickunas

    Keith Mickunas Cinematographer

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    If you're running just an LFE test, then speaker settings don't matter. Can you turn down the amp on the sub at all?
     
  3. EricHaas

    EricHaas Supporting Actor

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    What do you mean "running just an LFE test." This is where my confusion comes in. I do not know whether the Avia calibration test is supposes to JUST balance the LFE against the other channels, or if it takes into account speakers being set to small and the sub handling all frequences below the crossover. Yes, I can turn the subwoofer level down. It is set to maximum right now which as I understand it is the proper setting.
     
  4. Vince Maskeeper

    Vince Maskeeper Producer

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    Avia doesn't have a dedicated LFE tone. Its bass tone is on the main channel, rerouted with proper bass management. You must have the speakers set to small to properly calibrate with AVIA.
    Having no LFE tone is Ok, and rerouted bass will provide proper calibrated levels as long as the LFE pad toggle in your receiver setup menu is in the highest position.
    If you turn the sub output level on the receiver down to -10 and cannot get the proper calibrated level, reduce the amplifier input gain (the knob on your sub amp, or on the sub itself).
    See also:
    http://www.hometheaterforum.com/htfo...threadid=58466
    -V
    PS: Anyone who gets "dramatically" more bass when setting the speakers to small, your speakers shouldn't be set to large - they should stay on small.
     
  5. Keith Mickunas

    Keith Mickunas Cinematographer

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    I haven't used Avia but I assume for the subwoofer its passing an LFE, the .1 in 5.1, signal only. If you set your speakers to large and lfe to sub only, you should find that when you run the sub test from avia, you only get sound from the sub. So when using this test, the small/large settings are inconsequential as no signal is going to your other speakers. You should calibrate your sub according to the instructions regardless of speaker setting.

    When a full range signal is sent to all speakers and an LFE signal is provided at the same time, such as with a loud explosion, and your speakers are set to small, then you'll find the sub putting out a lot of volume. It will be combining the low end of the signals from the other speakers along with the LFE. But this shouldn't matter during calibration.

    There's another thread about 5.1 speaker balancing currently near the top of the list that Vince has added some info on sub calibration. Check that out.
     
  6. Vince Maskeeper

    Vince Maskeeper Producer

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  7. Keith Mickunas

    Keith Mickunas Cinematographer

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    Well, I'm glad I bought VE and not Avia then. I think my first sentence gave enough information to show that he should try it on his own or do a bit more research since I obviously wasn't claiming fact.
     
  8. Vince Maskeeper

    Vince Maskeeper Producer

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  9. Keith Mickunas

    Keith Mickunas Cinematographer

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    I just thought of something. Are you saying the only way to calibrate a sub with Avia is to have your speakers set to small? What a bone headed decision on their part. I realize that is almost always better to run the speakers at small, but that's pretty stupid for a test disc to assume.

    Forgive me for making an assumption about Avia because its so poorly designed, but the rest of my post is correct. If he was using a disc with an LFE signal, then I'm pretty damn sure I didn't say anyting false.
     
  10. EricHaas

    EricHaas Supporting Actor

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    The only problem I have with it is that Avia does NOT tell you to set the speakers to small for the test. But yes, speaker setting makes a huge difference. Set to small, the sub must be moved *8* notches lower than when set to large. So I just need to set the amp level down? Thanks.

    I must say at the properly calibrated level the sub seems low to my ears. I guess I have been running it hot.
     
  11. Vince Maskeeper

    Vince Maskeeper Producer

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    Keith,
    Breathe deep. No one is questioning your knowledge of the topic- I was just try to be clear to the original poster who is obviously confused on the issue that the info you provided will not help them. What you posted could easily serve to confuse someone worse if they don't have as frm a grasp of the concepts as yourself.
    I don't think the Avia decision is "boneheaded" in the least. 99.9% of systems should have their speaker set to small- and if Avia forces those who are currently incorrectly large to go small, I'm a big fan.
    Also, you don't have to leave the speakers set to small after calibration-- the settings you arrive at in terms of level will still be correct after switching back.
    This lack of a LFE tone does however overcome potential problems with the famed LFE pad that no one can seem to figure out how to set correctly.
    By taking the LFE track out of the equation, you bypass the complexities of the needed 10db SMPTE boost and all the confusions associated with it. Granted, calibration with improper LFE position will result in incorrect playback for both AVIA and VE- but doing it with incorrect LFE position with VE might result in speaker damage.
    Guy Kuo from Ovation (the people who designed AVIA) hangs here-- maybe he can drop in and some further thoughts on advantages of using main channel signal vs. dedicated LFE.
     
  12. EricHaas

    EricHaas Supporting Actor

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    [reveals ignorance once again]

    Uh, what exactly is the "LFE Pad"?
     
  13. Vince Maskeeper

    Vince Maskeeper Producer

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  14. Jeffrey Forner

    Jeffrey Forner Screenwriter

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    Vince;
    I have a question for you regarding the LFE pad. On my receiver, an Onkyo 575X, the LFE pad is as you described for Dolby Digital soundtracks. There's a setting at 0, -10, and one where the LFE is off completely. I have always set my LFE pad at 0 as you suggest.
    However, the pad for DTS tracks is slightly different. The LFE can either be shut off completely, set to 0, or set to +10. Since you say that the LFE pad should always be set to the highest level, does that mean I need to set it to +10 on my receiver? I currently have it set to 0. Thanks.
     
  15. Vince Maskeeper

    Vince Maskeeper Producer

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