A Discrepancy Between Video Essentials and Avia?

Discussion in 'DVD' started by Kevin M, Oct 25, 2003.

  1. Kevin M

    Kevin M Producer

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    I decided to relax and to listen to some music today so I put in The Beatles Works vol.2 and as I got to a track that was mono I noticed that the sound was decidedly directed towards the left rather than centered as a mono signal should be in stereo mode especially as I was seated in the sweet spot, so I thought "well it's time to re-calibrate" so I got out Avia and my sound meter and went about the prosess as usual. After I was done I decided just for the hell of it to see if the Avia calibration was as accurate if I checked it with Video Essentials....much to my surprise it wasn't, on Avia I had all channels about as perfect as I could get it but checking it with VE's sound tests I found the Left channel was lower than the rest and the center was higher....HUH?

    Have there been reports of differences between Avia & VE sound calibration levels? If so then which is correct/more accurate?
     
  2. Kevin M

    Kevin M Producer

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    Damn, nobody has noticed this before? Is it just my copy(ies)?
     
  3. Kevin M

    Kevin M Producer

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    Almost a year later......anyone?
     
  4. TimRP

    TimRP Stunt Coordinator

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    I don't have DVE so I can't help you, but I will bump the thread for you someone should have an answer for you and what thier results are.
     
  5. Jeannette Walsh

    Jeannette Walsh Stunt Coordinator

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    my guess is there are very few people that have both so doing a comparison would be kind of hard.
     
  6. Gary Seven

    Gary Seven Grand Poo Pah

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    I have Avia but use my receiver's pink noise coupled with a SPL for audio calibration.
     
  7. Brian L

    Brian L Cinematographer

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    I have Avia, DVE, VE, Ultimate DVD Platinum, Chesky's Ultimate DVD, Delos Surround spectacular, Delos DVD Spectacular....

    Oh, and I also use the internal tones too.

    Get the picture? I am a slut for calibration discs. And no two discs have ever produced the exact same results.

    There may be mastering difference, but I think the root cause is that none use the exact same test tones in terms of frequency content, and thus will produce different results in room when measured with an SPL meter.

    FWIW, the guys at Dolby Labs (Roger Dressler) has said many times to just use the internal tones, and be done with it.

    One more thing; Avia is authored at -20dbFs, while VE is -30 dbFs. That means Avia should be calibrated to 85dB, while VE requires 75dB, all other things being equal (which they never are).

    BGL
     
  8. Edward J M

    Edward J M Cinematographer

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    I have DVE and Avia. Except for the aforementioned 10 dB difference in encoding levels, the test tones for each channel are very close to parity; maybe 1-1.5 dB difference at the most. IOW if Avia reads 85 dB, DVE might read 76 dB, etc.

    The DVE subwoofer calibration tone definitely is encoded 10 dB too hot and has an authoring error. In addition, it is a wideband signal with strong content to about 15 Hz, which exacerbates the problem if you have a sub that digs deep and you also have room gain.

    Combine the authoring error, the wideband signal, and room gain, and the DVE sub tone ends up being anywhere from 12-14 dB too hot when calibrating. I have a definitive thread on this issue over in the Speakers and Subwoofers section; the last post was probably less than a month ago.
     
  9. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    Yeah, we went into WAY too much detail to figure out the DVE subwoofer tone problem. [​IMG]

    The difference in calibration is probably due to the tones using different bands of frequencies. I don't know about VE, but DVE's tones are very wide whereas Avia uses a narrower set of frequencies.
     
  10. Clinton McClure

    Clinton McClure Casual Enthusiast
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    I always choose to use pink noise from my A/V source unit (IE: DVD player) rather than internal tones from a receiver. If you use internal tones from your receiver and your source unit outputs the sound of each channel at a slightly different level than said receiver, your sound field can be a bit skewed. Personally, I calibrate with VE.
     
  11. Edward J M

    Edward J M Cinematographer

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  12. Kevin M

    Kevin M Producer

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    I don't have DVE yet so I use Avia for most of my HT calibrations because unlike the original Video Essentials it's navigation is painless and the video & sound tests are pretty comprehensive, I do use VE after the calibration is set for one specific test, the "walk around the room in voice".

    I personally use the sound tests on the calibration DVD to set individual levels and then I use the receivers internal tones to set overall sound level (roughly 65 to 70db as 85db is just too loud for my location...for some reason the neighbors don't like their windows rattling during LOTR many low spots).
     
  13. Brian L

    Brian L Cinematographer

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    FWIW, this is a link to a thread over at Spot that was cross referenced to the LFE discussion here.

    http://www.hometheaterspot.com/htsth...&o=365&fpart=1

    Anyway, there is a poster (Chad) that had some interesting comments about some shortcomings in the video side of DVE, particularly as it relates to the sharpness pattern, and why Avia and DVE can produce very different results.

    BGL
     

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