Widescreen Review CLICK here to read the Widescreen Review article below, or CLICK here to open a PDF of the original Widescreen Review article Ultimate AV CLICK here to read the Ultimate AV article below, or CLICK here to link to the original Ultimate AV article by Danny Richelieu The Switch To High-Definition Video Equipment Is Ruining My Home Theatre Experience Okay, so now that I have your attention, let me explain. While video quality has improved dramatically, and the fidelity and spatial dimension of the audio has increased substantially as well, I still find that something is not quite right, and it is intruding into my movie viewing experience, something that I have only recently been able to identify. Here’s the problem…my ear/eye/brain interface is being confused by something that we all used to simply call “lip sync.” Though subtly different on all content, in general the movies and other video material we receive have the audio and video signals pretty well coordinated so that the dialogue matches the visual cues we see of the actors’ mouths moving. Special effects, like explosions or car tires screeching, seem real to us because they appear to be timed properly with what we see. When viewed in standard-definition (SD), we are not aware of there being any problems with the synchronization. As specified by Advanced Television Systems Committee (ATSC), synchronization is to be within 1 frame, or 1/60 of a second (17mS). Where the difficulty begins is with the better, high-definition capable video products. Video processing of an incoming image requires that the display device or processor must store one or more frames of video information in order to perform the mathematical processing necessary to produce the quality image you expect. Some what basic video processors will store frames for deinterlacing, scaling, and some types of image enhancement. Each of these temporal processes uses several megabytes of high-speed Random Access Memory. At least two frames of video (34mS) would be used to perform this level of performance. Additional levels of visual improvement require additional frame storage. The most sophisticated processors available today are storing as many as five video frames for a total of 85mS, or almost 1/10 of a second. The problem will only get worse. There are processors coming in the future, which are planning twice this much internal delay. If this were not enough, there are several other possible sources of delay within our content delivery system. Often the cable and satellite systems many of us rely on for an HD feed to our homes are creating part of the problem. Whether it is due to the HD conversion at the head-end, or delays within the set-top box equipment itself, we are sometimes forced to start with less than perfect synchronization to begin with. Then we add video processing in our homes and it’s no wonder it sometimes looks like we’re watching an early Japanese science fiction film. It’s not that the problem has gone totally unnoticed. There are a few surround sound processors that allow you to add varying amounts of delay to their output. Though useful, the feature is often hidden deep in the menu structure and not easily accessible for fine-tuning. Further, to be able to correct for each video source in the system, one would want each input to have its own adjustable delay value. As a further confirmation of the problem, at least one of the new video processing chips on the market actually includes variable audio delay as an on-chip feature. The compressed audio ends up running through the video chip to match the delays. This, however, is only a partial solution, as it is not easily adjusted for delays caused outside the chip. Enter The Alchemy2 Digital Delay Line Alchemy2 is a new company formed by several of the original members of the Audio Alchemy team. Like products from that company, the D2L (Digital Delay Line) [three-letter acronyms seem to follow these guys around…] is a small, elegantly finished metal enclosure “no larger than it needs to be,” according to Peter Madnick, one of the founders. The input to the D2L can accept PCM, Dolby™ Digital, DTS™ encoded material or anything that can be transmitted in the S/PDIF format. The box does not decode the incoming signal, in effect, it simply stores it for a pre-selected period of time and then sends it back out. The box is inserted between the digital outputs of your video source and the input of the surround sound processor. As can be seen in the picture, there are four buttons (input select, bypass, delay + and delay -), plus a three-digit LED display. The display tells you what your delay selection is. Settings range from 000 to 255 (more about this later). The current model supports two inputs and two outputs, (one coaxial and one optical), the next model will add a second set of coaxial and optical inputs. Audio is provided on both a coaxial and optical output, and both outputs are active at the same time. A three-pin 3.5mm mini jack RS232 interface is provided for use in automation systems and for future software upgrades. Power is supplied from a small wall-wart power adaptor (another old Alchemy habit). To use the D2L, you first select the input you wish to use. The display will toggle from one to the next with each press of the Input Select button and show a rather cryptic “in1,” “in2,” “in3,” “in4.” The input selection soon disappears and is replaced by the detected sample rate of the selected input (44.1, 48, 96, or 192 kHz) or with “- - -” if there is no input or it cannot be identified. A few moments later, the display indicates a relative delay value. This will be a number from 000 to 255, even though the actual delay may be different, depending on what the incoming sample rate is. According to the chart in the instruction manual, the D2L can provide 1.4 SECONDS of delay at 44.1 kHz, down to about 300mS at 192 kHz. Apparently, the designers felt that the use of a three-digit display with a relative scale was more useful than an actual readout in milliseconds because it allowed the user to not have to consider the sample rate in their determination of a delay. One minute after the last selection is made to the D2L the display will start to dim, a nice feature given the bright red display. A touch of any button will “wake up” the display. The D2L stores the delay setting for each input source, as well as the last input source selected. Thus, you can have one set for DVD, another for cable, and a third for satellite. Home Theatre, Fixed In use, the D2L did exactly as it was designed to do. I put in a disc, and simply adjusted the + and - buttons until I was happy with the “lip sync” (easiest to do with dialogue) and sat back and enjoyed. The use of the bypass button lets you compare delay to no delay. If you are like me, you will stop doing that after a few days and just find your setting and forget the box. So far, all of the DVDs I have reviewed have sounded best with the same delay settings, maybe within one or two clicks. Cable and satellite are a different story. Settings appear to vary widely, with each channel even varying from movie-to-movie. I found myself making note of the display settings so I could compare and, hopefully, detect a pattern. None has appeared yet. An additional interesting effect of the D2L in the Widescreen Review Reference Holosonic™ Spherical Surround™ Laboratory System was to significantly improve the effect of the D-BOX Odyssee Motion Simulation System. Where before there were times when I felt that there was a noticeable mistiming of the D-BOX effects, I now see that this effect has been a manifestation of the same problem. Fixing this delay had a profound effect on the D-BOX experience. In summary, I found the Alchemy2 D2L to be a fine product, and well worth the small price of $399 for all of the improvement it has made for the WS Rreference system. Welcome back to Peter and his group! SPECIFICATIONS Signal Format: S/Pdif Signal Type: PCM, Dolby™ Digital, DTS™ Frequency Response: No effect on incoming signal Signal To Noise Ratio: No effect on incoming signal THD: No effect on incoming signal Delay Range: up to 1.4 Seconds @ 44.1KHz, proportionally less as S-R increases. Connectors: (1) RCA input, (1) Optical input, (1) RCA output, (1) Optical output, (1) 2.5mm DC power jack, (1) 3.5mm mini-jack RS232 port General DDL Dimensions (WHD In Inches): 4.25 X 2.125 X 5.25 DDL Weight (In Pounds): 1 Power Supply Dimensions (WHD In Inches): 1.75 X 1.25 X 3.25 Power Supply Weight: 0.25 lb Power Consumption: 5 Watts Warranty: 1 yr P&L Price: $399.95 Designed And Assembled In The United States By: Alchemy2 3533 Old Conejo Road, Suite #107 Newbury Park, CA 91320 ===== comments from the manufacturer: The D2L has been upgraded to include a wireless remote control, internal IR code learner (which allows D2L learn and be operated by any IR remote), and now comes with the new Monster/ISF HDTV Calibration DVD. -- the Alchemists What’s the most annoying flaw in digital programming from DVDs or HDTV? Video artifacts? Macroblocking? Freeze-ups? Standard definition commercials? David Letterman? None of the above. It’s non-synchronized audio and video—the lip sync issue. No, we’re not talking about Ashlee Simpson. We’re referring to the sound and image being misaligned in time. People on screen start talking before they open their mouths. Explosions are heard before they’re seen. The cart, in short, arrives before the horse. Riding to the rescue is the D2L, or Digital Delay Line ($400) from Alchemy2. Alchemy2 is a new company founded by Peter Madnick, the former designer for both Audio Alchemy and Entech (the latter a one-time subsidiary of Monster Cable). While both of those brands are on, um, indefinite hiatus, Alchemy2 continues their tradition of providing useful and reasonably priced audio/video niche products—products that other companies seem to have overlooked, or insist on charging premium prices for. The D2L is their first (and so far only) product. The Problem Some of us rarely experience the program- and playback-dependent lip-sync phenomenon, but for those who do it’s like being trapped at a Godzilla film festival. Or a Charlie McCarthy retrospective. Before long you want to turn off the sound and turn on the subtitles. Or read a book. Lip-sync can originate at either the broadcast or display end. Broadcast problems (including satellite and cable) have been prevalent enough to drive SMPTE (the Society of Motion Picture and Television Engineers) to establish an Ad Hoc group to study the issue. On the receiving side, both video displays and the scalers and deinterlacers (video processors) we use with them can conspire to delay the image until it is obviously out of sync with the sound. Digital displays sometimes buffer the video before displaying it. Processors can introduce additional delays. While neither of these lags by themselves will always be enough to cause a visible problem, they can add up. A delay of merely one frame results in an image lag of 33.3 milliseconds (at a frame rate of 30fps). This doesn’t sound like much, but most viewers can spot it. What to Do? While a situation in which the sound actually lags the video is theoretically possible (and would most likely originate at the production end rather than in the playback system), it isn’t likely. I know of no consumer devices that will correct for this (they would have to delay the video, not the audio). The far more common scenario of the lagging picture is a different story. More and more surround pre-pros and AV receivers (and even the occasional DVD player, though this won’t help with HD broadcasts) are including adjustable audio delay circuits. They delay all channels equally, unlike the individual channel delays that are part of the initial system setup and calibration. Many of these circuits have a limited range. While a delay of 4 frames (133.3ms) should be sufficient to accommodate any likely mismatch with the video, there might be instances in which you need even more. And there are some older—and otherwise still very good—products that lack this feature entirely. The Alchemy2 D2L fills the gap. It has one function and one function only: to accept a digital input, delay it, and output the delayed digital audio to a digital input on your receiver or pre-pro. A Quick Look There is little to describe about either the layout or functionality of the D2L. It has two digital inputs and two digital outputs (in both cases, one is coaxial, the other TosLink), and both outputs are active at all times. Power comes into the unit from a wall-wart transformer. And there’s an RS-232 input for use with automated systems or for software updates. The D2L will handle PCM, Dolby Digital, and DTS program material. It will function with sample rates of 32, 44.1, 48, 88.2, 96, and 192kHz. Most of the video sources you’ll want to delay will be at a sample rate of 48kHz. Why would you want to route audio-only program material of say, 96kHz, through the D2L? The only reason I can think of is that the source device is used for both audio-only and video sound, as with a DVD/CD player. The D2L’s front panel offers a bypass switch to eliminate any delay, an input selector that toggles between Input 1 and Input 2, and controls that allow you to set the delay at one of 256 steps (including Bypass). There is also a display window that shows the audio sample rate (briefly, when an input is selected), the input chosen, and, in its normal operating state, the delay setting. And Alchem2y didn’t forget the environment in which many D2Ls will be used- the display panel dims automatically a few seconds after the delay indicator appears. The number that shows in the display window indicating the delay setting is a reference number, not the display time. The actual delay depends on the sample rate. As noted in the brief owner’s manual, at a 48kHz sample rate (used for both Dolby Digital and DTS), each step changes the delay by 5.27ms. That means for Dolby Digital, the available delays range up to 1.34 seconds (0.00527 x 255). In Use I’m perhaps not in the best position to evaluate a lip sync device, as I rarely have a troublesome lip sync issue in my system. But it was easy enough for me to experiment with delays to see how well the D2L operates by deliberately using it to misalign the audio-video sync. The D2L was so simple to set up and use that I began, like many of you would, without referring to the instructions. I assumed that the numbers on the front panel were actually milliseconds, so I initially ran the delay all the way up to 255, which I took to be 255 ms. The soundtrack from Star Trek: Enterprise, which I was reviewing at the time, was now so out of whack in time that one character’s lines sounded like they were coming from the next character who spoke. Wow, I thought, they can sure say a lot in a quarter of a second! But as I found out in short order from the instructions, that 255 setting was actually 1.34 seconds at the Dolby Digital sampling rate. When I dropped the delay down to an indicated 50 (about 264ms at 48kHz) the lip sync was just bad enough to be readily apparent. When I dropped it down to 20 (about 105 ms at 48kHz) it was, for me, no longer noticeable. Your mileage may vary. Just remember as a rule of thumb that for most current video sources with a digital soundtrack, the delay, in milliseconds, is approximately five times the number indicated on the display. What this means is that the D2L has more than enough range to match any conceivable video delay, and far more than I’ve seen offered on any pre-pro or receiver. It does exactly what it is supposed to do. You can also set different delays for the two inputs, or easily fine tune the delay for different program material. Yikes! I’ve just discovered the videophile equivalent of an analog LP fan setting a different vertical tracking angle for each recording! In both situations, using a compromise position would be far less tedious. I did experience one potentially serious problem with our review sample. The first time I touched it, after it had been running flawlessly for an hour or so, the sound immediately cut off, though the front panel display and controls continued to operate. My first thought was a static electricity problem—though there was no obvious static discharge. It took a couple of worried minutes before I was able to re-engage the unit by some random combination of disconnecting the power, re-connecting it, and flipping back and forth between inputs until it locked on again. I was afraid that I’d fried the unit, but it did come back on, good as new. After I finished the review and was willing to risk another potentially damaging shutdown, I tried touching it again. This time there was a distinct static discharge, and the unit malfunctioned once more. All of its indicators continued to work, as before, but there was, again, no sound. After several minutes I was able to reengage the unit. But it took longer this time and I came very close to giving up on it. After that, I was careful to touch a less sensitive piece of gear—or a nearby metal rack, before touching the D2L. If I did that first, there was no problem. Subsequent to receiving this review for a fact check, Alchemy noted that they have not had field reports of a similar static electricity problem. But they also report locating a spot in the circuit where a ground problem could occur in manufacture. They plan to upgrade their QC procedures to prevent such problems in the future, and have offered to send us a second sample. I will append a report on that new sample to this review as soon as possible. I should also note that I didn’t hear any deterioration in the audio from the D2L’s delay, even at its maximum. Peter Madnick of Alchemy2 argues that some of the delay circuits provided in pre-pros and receivers can compromise the audio. I can’t say I’ve ever experienced that; most of the electronics I’ve been using have been high-end enough that the manufacturers can include quality delay circuits. Conclusions Apart from its apparent sensitivity to static electricity, the D2L works exactly as advertised. It is perhaps a little expensive for the budget-priced electronics that might have the most use for it, but even higher up on the pre-pro or receiver price ladder there are many products that don’t offer anywhere near its flexibility. There’s very little else like it on the market. Highs and Lows Highs Does the job without any side effects Extremely wide range of operation at the most common audio-for-video sampling rate Lows Sensitive to static electricity. Specifications Signal format: S/pdif Signal type: PCM, Dolby Digital, DTS Frequency response: no affect on incoming signal S/N ratio: no affect on incoming signal THD: no affect on incoming signal Inputs: coaxial (RCA) and optical (TosLink) Outputs: coaxial (RCA) and optical (TosLink) Other: power jack and RS-232 Delay range: up to 1.4 seconds at 44.1kHz, less at higher sample rates Size: 4.25” x 2.125” x 5.25” (WxHxD) Weight: 1lb Manufacturer: Alchemy2 www.Alchemy2.com Review System Display Yamaha DPX-1200 video projector Sources Pioneer Elite DV-59AVi DVD player Scientific Atlanta Explorer 800HD HD cable converter/hard disk recorder AV receiver Denon AVR-5805 Speakers Revel Performa F32 L/R, C32 center, M22 surrounds, B15 subwoofer Cables Ultralink, Monster, and DVDO component, DVI, and HDMI video cables Screen Stewart Studiotek 130 (78 inches wide, gain 1.3, 16:9) ===== comments from the manufacturer: We confirmed that the static sensitivity identified by Tom Norton was because the back panel wasn’t grounded through the RS232 jack -- due to a missing ring nut on the beta sample he received. Not to worry, it was taken care of in production. -- the Alchemists