just calibrated with the new sound and vision disk!

Discussion in 'Archived Threads 2001-2004' started by Greg Br, Jan 20, 2002.

  1. Greg Br

    Greg Br Second Unit

    Joined:
    Dec 13, 2001
    Messages:
    437
    Likes Received:
    0
    Trophy Points:
    0
    Since I first bought all this HT equiptment I have been waiting for this new disk to come in. I received it Sat. and calibrated last night. I have never used the Avia or VE disks before so I have no reference as of yet. I can say that using this disk is about child proof, its that easy. The hardest thing on the whole disk was adjusting my contrast on the video portion, and that was just the pattern they used. The disk goes through 5.1 theory and equiptment needed, wire setup, video and audio calibrations and upgrades. The audio portion was simple but left me with one major difference from all the posts I have read, and that is to calibrate the audio it said to turn the volume to the listening level that is normal for you to use, in my case that was -27(on a yammy rxv-1000), not the 00 level I have heard often.

    The second question that arose was the sub auio test, the sub test used noise from the left front main and the directions were to turn my base up till it read the same level on the spl. I did this but my bass was only turned up to the 10:00 position(I had been using it at about 1:30 or so on my JBL PB-12(already ready to upgrade that)). I popped in Kung Fu on the matrix and the bass was just nowhere near the volume that I enjoy or expected compared to theater levels. I am not sure if I screwed this calibration up or what.

    There are other audio test paterns that were on the main menu that I have not tried yet, I just ran through the video and all the chapters.

    I have to say for a beginner this is a no-fail disk for calibrating. I could not believe the difference in my video after the changes, I must have been blind for the past 3 years since I got my big screen. The audio was not that much of a change, I had used the yammy's test tones and the spl last week and I must have did ok as my changes were minimal.
     
  2. Bobby T

    Bobby T Supporting Actor

    Joined:
    Mar 13, 2001
    Messages:
    583
    Likes Received:
    0
    Trophy Points:
    0
    I tried this disc over the weekend. My only question about it was on a couple of the video modes on my 32 wega. According to the test pattern for contrast it would have me turn the contrast all the way up. This didn't seem right so I backed down on the contrast some.Any one else try this disc out?
     
  3. Greg Br

    Greg Br Second Unit

    Joined:
    Dec 13, 2001
    Messages:
    437
    Likes Received:
    0
    Trophy Points:
    0
    The contrast test was confusing, trying to get all the lines to show the same brightness and I did notice the black lines on the crosshaires changing much, I ended up setting the contrast relatively low per the conversation the narrators had about it being genarally set to high on most televisions.

    How did your sub calibration go?
     
  4. AbelM

    AbelM Second Unit

    Joined:
    Dec 28, 2001
    Messages:
    374
    Likes Received:
    0
    Trophy Points:
    0
    What disc is this, and where can you get it?
     
  5. EarleD

    EarleD Supporting Actor

    Joined:
    Aug 27, 2000
    Messages:
    728
    Likes Received:
    3
    Trophy Points:
    0
    Does the disc support 6.7/7.1 setups? My love my VE disc but the lack of rear center tones makes it tough to calibrate the rear centers.

    thanks

    Earle
     
  6. Guy Kuo

    Guy Kuo Supporting Actor

    Joined:
    Mar 6, 1999
    Messages:
    581
    Likes Received:
    0
    Trophy Points:
    0
    Yes, both DTS and DD test with center rear surround channels are supported on the HTT disc.

    Those "contrast" settings you were doing to make the lines the same brightness sounds awfully like the SHARPNESS control and pattern, not contrast.

    Setting contrast is a bit harder for most people. The pattern in AVIA is very similar in design so I'll repost some info which should help with HTT as well.

    -----

    Black and White Level Adjustment

    Let's first examine what the black level (brightness) and white level (contrast) controls actually do inside the set and the performance limitations that set the bounds within which you should keep the controls.

    Within the television, there are video amplifier stages. Somewhere near the end of the video signal processing chain, just before the signal reaches the final amplifiers, the black level and white level controls operate. At the amplifier stage where these two controls operate, a small video signal undergoes amplification before being passed to the next circuitry stage. The higher the signal, the higher the associated beam current and hence more light output. (I'm ignoring the inverted polarity of the signal to simplify this discussion.)

    Essentially, the black level control sets the baseline (bias) level of the amplifier stage. Think of it as setting what the lowest point (black) upon which the rest of video signal rides. The white level control sets how much amplification is performed on the signal. A higher white level setting means that video signal excursions are larger.

    The combination of black level and white level controls allows you to control the amplitude and baseline of the video signal. If the display were capable of unlimited light output as video signal amplitude increases, one would only have to worry about light output and the blackness of black when setting these controls. Real life displays have limitations and exceeding these limits can damage or shorten a display's life.

    I'll concentrate on CRT displays for now. The video signal is processed and eventually delivered to the red, green, and blue electron guns. A higher signal makes the gun emit more electrons and produce a brighter spot on the screen. CRT's are limited in how much beam current can be safely used. If too high an output is attempted, the phosphor at the front of the screen can be physically damaged by the electron beam. It isn't practical for you to measure the beam current so we use the proxy of beam defocusing to estimate when too much beam current is being used. As beam current increases, it becomes more and more difficult to confine it to a sharply focused beam. For most CRT's the point at which beam focus worsens is below the point at which phosphor damage can occur. By staying below this point of "blooming," you avoid immediate phosphor damage.

    There are other limitations of usable beam current. Heat is produced by the current flow. Direct view CRT's use a metal mask to help direct the red, green, and blue beams to the appropriate color phosphors. A high beam current can heat up the metal mask and warp it. This is seen as a sudden shift in color of the screen and could indicate the danger of permanent mask warping. Obviously you want to keep your controls below this point.

    Projection CRT's are driven at much higher beam currents, so high that liquid cooling of the phosphors is virtually required. This means that projection sets are even closer to the physical limits of the phosphors and particular attention must be paid to never overdriving the tubes.

    Over time, phosphors age and solarize. The more light emission they are forced to produce, particularly if near maximal output, the faster their light output drops. This is why bright, fixed images can permanently burn themselves into a screen. By limiting beam current to reasonable levels, you slow this process and reduce the risk to your screen.

    The electrons are emitted by a heated filament, the cathode, of a CRT display. The cathode is coated with special rare earth elements to improve electron emission. Over time, this coating loses its effectiveness and you notice this as a blurring of the electron beam even at low light output. The aging process causes a larger portion (other than the tip) to become involved with emitting electrons. Since the beam spot is essentially an image of the active region of the cathode, this increase in active region appears as enlarged (blurred) electron beam spot size. Higher beam currents accelerate this aging, but not to the same degree that it damages the phosphor.

    Now we've gone over some reasons to keep white level down in order to protect the display. There are also imaging quality reasons. We've already mentioned the defocusing of the beam when current is too high. This blurs the image and reduces resolution. Also, running too high causes the relationship of input signal to output light to be altered. If this runs outside the "linear" range of the CRT, the relative brightness of signal levels from black to white are distorted. You perceive this as something being unrealistic or wrong with the contrast of a picture.

    The high voltage supply used to produce the electron beam is often derived from the horizontal deflection circuitry of the television. If beam current demands are too high, the demand can drag down the horizontal deflection circuit. You see this as a horizontal geometry distortion. Hence the visible bending of the left and right vertical lines on either side of a Needle Pulses pattern in AVIA. Although not something that will damage a set, this type of geometric distortion degrades the image. By keeping white level down, you also avoid this problem. Some displays are designed such that this effect doesn't occur. In these displays, you never see the vertical lines bend, however you will still see blooming.

    In short, white level should be set to avoid increasing the risk of permanent damage to the display, slow aging of the phosphors & cathode, and improve image resolution, gamma response, and geometric accuracy.

    Black level, which determines the baseline upon which the video signal rides sets the appearance of black, not how much overall light is output by the display. This needs to be set at the lighting condition which is to be used for viewing because the correct setting varies with ambient light. Too high a black level washes out the picture. Too low a black level causes shadow details to be clipped and displayed as black.

    Most consumer displays complicate setting of black level because they do not hold black level constant as overall picture level changes. That is, black is displayed differently depending on how bright the rest of the image is. This is also called imperfect DC restoration or clamping. The solution in this case is to bias the display with a moderate picture level image while setting black level. This allows you to arrive at a compromise level which works for most images.

    Test patterns traditionally used a blacker-than black signal to help indicate when black level was correctly set. After all, you can't actually make the display any blacker than black so if "black" on the display is brighter than it should be the even darker (signal wise) BTB signal would appear be visible as a dark feature. When the BTB and black just appear identical, the display is correctly set to make black appear black.

    Many DVD players and some video processors don't pass the BTB signal so this method of detecting when black level is correctly set doesn't always work. Also, the traditional patterns unfortunately aligned edges of pattern features with each other leading to optical illusions which confused viewers whether or not the BTB bar is visible. For these reasons AVIA uses "Black Bar" patterns to indicate correct black level. These are a pair of animated bars which move back and forth on screen. The motion makes it easy to see if a bar is visible and helps avoid the ambiguity of optical illusions of aligned, fixed lines. One bar is very near black, the other slightly brighter. When black level is correct, the darker black bar is just very barely visible. If black level is too low, one or both bars disappear. This allows one to find correct black level whether or not equipment passes blacker than black.

    The situation is different on LCD's because the usual phenomena of geometry distortion and electron beam defocusing (blooming) don't occur with LCD's. Another limiting factor comes into play. LCD control circuitry in LCD projectors have a relatively abrupt point above which video signals become displayed as white. We call this "white clipping" on AVIA. electron guns.

    Basically, if you set white level too high on an LCD projector you will find that near white details turn into white instead of something that is darker than white. Highlight details are hidden and the image looks solarized. Finding the white level setting which avoids white clipping is the key to maximizing LCD projector light output without degrading image quality.

    As an aside, digital domain video displays can also exhibit a similar clipping effect when the video signal cannot be represented within the bit range of the system. You can sometimes see this on computer monitors displaying video from a DVD-ROM.

    AVIA has new moving "white bars" in its main pattern for adjusting white level, the Needle Pulses + Log Steps pattern. You'll find a pair of near white bars which move back and forth. If you set white level too high on a LCD projector you'll see one or both of these white bars become white ( and disappear since you can't see white on a white background). The maximal white level setting is found by adjusting your LCD projector to just below the point at which the rightmost (brighter) white bar becomes white. Once that point is found, you know the max usable white setting for your LCD projector.

    The Needle Pulses + Log Steps pattern in AVIA serves as a unified tool for both CRT and LCD display white level adjustment by combining tests for geometry distortion, blooming, gray scale linearity, and white level clipping into a single pattern.

    Once the limits for white level are found for your display. The next step is to drop down to a white level setting which is below the max and still produces a white which appears white rather than gray.

    Black level is set the same way with AVIA on both LCD and CRT projectors.
     
  7. Alex Giese

    Alex Giese Extra

    Joined:
    Dec 4, 2001
    Messages:
    19
    Likes Received:
    0
    Trophy Points:
    0
    Can anyone with the new S&V disc tell me if it has closed captioning on it? If not, does the Avia or VE have it, or at the very least, have English subtitle?
     
  8. Greg Br

    Greg Br Second Unit

    Joined:
    Dec 13, 2001
    Messages:
    437
    Likes Received:
    0
    Trophy Points:
    0
    oops! that was the sharpness adjustment that I struggled with, sorry. I did not have any problem with the Contrast test.
     
  9. Jim A. Banville

    Jim A. Banville Supporting Actor

    Joined:
    Jun 20, 1999
    Messages:
    630
    Likes Received:
    0
    Trophy Points:
    0
    Guy, I have what seems to be a fairly simple question -- when the average consumer TV is set to have a "correct" black level using AVIA or any other test pattern generator that adheres to NTSC standards, would a totally black field (0 IRE?) from the DVD/test generator be equal in brightness to a TV that is turned OFF?

    thanks

    Jim
     
  10. Paul_Fisher

    Paul_Fisher Screenwriter

    Joined:
    Dec 27, 2001
    Messages:
    1,219
    Likes Received:
    1
    Trophy Points:
    0
    Jim,

    I live just up the road in Auburn, AL. Is there any good electronics stores to buy Home Theater stuff in Columbus? As you know there is nothing here in Auburn.

    Thanks
     
  11. David Head

    David Head Second Unit

    Joined:
    Jul 5, 1999
    Messages:
    302
    Likes Received:
    0
    Trophy Points:
    0
    Does this come with all three color filters like Avia?

    David
     
  12. Guy Kuo

    Guy Kuo Supporting Actor

    Joined:
    Mar 6, 1999
    Messages:
    581
    Likes Received:
    0
    Trophy Points:
    0
    An "average" consumer display doesn't have perfect DC restoration. That means the brightness of a black varies with the overall intensity of the picture. That means that a proper, compromise setting for brightness on a consumer set will cause a completely black image to glow a little compared to a set's off state. Setting brightness low enough to completely extinguish black to the same darkness as off will render near black detail too dark (black).

    The HTT disc comes with only a blue filter. The tests were redone to reduce or eliminate the need for a red filter in looking for and correcting red push.
     
  13. Bobby T

    Bobby T Supporting Actor

    Joined:
    Mar 13, 2001
    Messages:
    583
    Likes Received:
    0
    Trophy Points:
    0
    I've re done my TV with the contrast a lot lower. Dummy me did the setup the last time in the afternoon. I figure I had too much light in the room as I can't block it out totally. It looks a lot better now.
     
  14. NickSo

    NickSo Producer

    Joined:
    Jul 2, 2000
    Messages:
    4,260
    Likes Received:
    0
    Trophy Points:
    0
    Real Name:
    Nick So
    Is this new sound and vision disc as extensive and specific in the tests as VE or AVIA?
     
  15. Jim A. Banville

    Jim A. Banville Supporting Actor

    Joined:
    Jun 20, 1999
    Messages:
    630
    Likes Received:
    0
    Trophy Points:
    0
     
  16. Bob_M

    Bob_M Stunt Coordinator

    Joined:
    Apr 3, 2000
    Messages:
    194
    Likes Received:
    0
    Trophy Points:
    0
    The big question, is AVIA absolute now? Bob
     

Share This Page