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Felston DD740 Digital Audio Delay: Fix Lip-Sync Error for Good!
November 12, 2010 
When you watch TV or movies, do you ever notice how picture and sound are sometimes OUT OF SYNC? The presenter's lips don't move quite at the same time as their voice? Irritating isn't it. This is known as lip sync error. Even if you haven't consciously noticed lip-sync error (we avoid this impossibility by subconsciously looking away) research at Stanford University discovered it causes a negative impact on our perception of the characters and story. Lip sync error affects a huge number of displays, including modern plasma TVs, LCD screens, DLP TVs and digital projectors. What causes lip sync error? There are many causes but most boil down to the video signal being delayed more than the audio signal allowing speech to be heard 'before' the lip movement that produced it is seen. Digital image processing within broadcasts and within modern displays delays video and allows audio to arrive too soon. Sound "before" the action that produces it can never occur in nature and is therefore very disturbing when the brain tries to process this conflicting and impossible visual and aural information. How do you fix lip sync error? The only way to correct lip-sync error caused by delayed video is to delay audio an equal amount. The Felston DD740 digital audio delay solves lip-sync error by letting you add an audio delay to compensate for all the cumulative video delays - no matter what their cause - at the touch of a button on its remote. Unlike the audio delay feature found in most a/v receivers, the DD740 is designed for easy "on-the-'fly" adjustment while viewing with no image disturbance. This makes fine tuning for perfect lip-sync practical as it changes between programs or discs, and the DD740's 680ms delay corrects larger lip-sync errors common in HDTV. Questions? Email us at: lipfix@curtpalme.com
JETI Specbos 1201/1211 Reference Spectroradiometers with ChromaPure
November 10, 2010 
The Specbos 1201 and 1211 are the most affordable true reference color analyzers available on the market today. Just mount either on a tripod, facing towards the source, connect to ChromaPure Pro and use as you would any other color analyzer. At some point many professionals conclude that their work requires a reference colour analyzer. SMPTE has established standards for such a device. It must measure color accurately to within ±0.002 xy at or above 10 cd/m2 and luminance accurately to within ±0.5 cd/m2 for white field measurements. These are very exacting specifications that no tristimulus colorimeter can achieve, at least for chromaticity. For this level of accuracy you must have a 5nm spectroradiometer. Unfortunately, such devices are not cheap. The Photo Research and Minolta reference devices start at about $15,000 and go up to near $30,000. The X-Rite EyeOne Pro is reasonably affordable, but it is a 10nm device that cannot routinely achieve ±0.002 xy accuracy. Furthermore, in addition to being expensive, true reference devices also often suffer from practical limitations. They can be slow and have problems with low-light readings. Recently, a German company JETI Reference Instruments has developed two true reference spectroradiometers, the Specbos 1201 (also known in the U.S. as the Orb Optronics SP100) and the Specbos 1211, that solve most of these problems. First, they are relatively affordable, that is at least what passes as "affordable" in the context of reference devices. Second, both are reasonably fast for higher luminance sources, and the 1211 is speedy even with low luminance sources. They are also amazingly compact and portable and both include a nifty laser spotter that allows for accurate aiming. The only feature these incredible devices give up to the established Photo Research and Minolta competitors is stand-alone operation. The Minolta and Photo Research alternatives allow for aiming through optical sights and readouts on a small LCD screen. They are fully functional devices without a PC. In contrast, the JETI devices work only when attached to a PC via USB with custom software (such as ChromaPure of course!). For display/home theater calibration this is a non-issue as you'll be using calibration software anyway. Both units share a similar design and software support. Both achieve reference levels of accuracy. The differences? Well, the 1211 is larger than the 1201 and about 30% more expensive. But surely the most important difference is low-light sensitivity. The 1211 is MUCH more sensitive than the 1201. At light levels at or above 50 cd/m2 (14.6 fL) they perform similarly, but as you go lower than this the 1201 begins to take noticeably longer and longer to return a reading. At 4 cd/m2 (1.2 fL) the 1201 will take approximately a minute-and-a-half to return a reading. By way of contrast, at this level of stimulus, the 1211 chugs happily along returning a reading in about 5 seconds. This has profound implications for day-to-day use when calibrating displays. For this reason, the 1201 is best used for color management, when light levels are generally high, or as a reference device employed to create an offset for a field colorimeter, such as the Chroma 5 or Hubble. The 1211, on the other hand, can be used as a working or field color analyzer (one that is not solely only used to create offsets to make other faster meters accurate). Its speed and low-light sensitivity make it suitable for any calibration task—except perhaps reading black level—where the light level is so low even the 1211 often cannot cope. Fortunately, very low light levels can be accurately read with quite inexpensive instruments, such as the AEMC CA813 illuminance meter. The Chroma 5 will read down to about 0.01 fL, and the Hubble will read down to 0.001 fL. Confused about meters? See our
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