It's one of the most annoying and widespread problems in the home cinema world; it's probably been experienced at least once by most people reading this website; it's caused by a depressingly wide range of different problems; there's no knowing when it's going to appear; but when it does it can completely ruin your enjoyment of a film or TV. What are we talking about? Lip-synch error - when the movement of actors' mouths in the picture doesn't tally with the words they're saying on the soundtrack. Sometimes the problem can be so bad that even a Hollywood blockbuster can look like some poorly dubbed foreign language film.
Causes of lip synch errors include: failure by (especially digital) broadcasters to synch the audio and picture tracks correctly at source; digital TV receivers 'glitching' while decoding their pictures so that they're decoded slightly slower than the sound; the slowness of picture processing on one or two (especially older) DVD players; poor encoding of DVD discs, so that the audio track isn't timed correctly with the video one; and big differences in the length of audio and video cables in a system (a common situation for people using projectors).
By far the most common current cause of lip synch issues, though, is the picture processing employed by today's digital displays - be they plasma, LCD or DLP in nature. In fact, with flat panel TVs currently selling like the proverbial hot cakes, lip synch problems have started to become so common that a handful of higher end receivers and DVD players have started to add audio delay options among their feature lists.
But what can you do if you're experiencing lip synch issues and neither your amp nor your DVD player provides such audio delay options? Answer: get an external audio delay device such as Felston's DD540…
The DD540 is a rather unassuming little grey box that looks like an escapee from an intensive care unit or mad scientist's laboratory. But don't be put off; it's really a lot less scarily teccy than it looks.
Essentially all it does is sit between the digital audio output of your DVD player and/or Sky Plus Digital or Homechoice receiver and the digital audio inputs on your AV receiver, 'holding up' the audio signal by a user-adjustable amount until it tallies perfectly with the final video picture.
To set it up, you just plug it into the mains, insert the optical or coaxial cable from your DVD player/Sky box into one of the optical or coaxial input sockets on the DD540, then connect the unit's optical or coaxial output sockets to the digital inputs of your AV amp. And that, essentially is that.
The audio delay is adjustable in steps as small as one millisecond via a provided remote control: between 0 and 680milliseconds for a standard digital audio feed, and 0 and 340ms for a high resolution, 96kHz feed. What's more, you can set up to six preset audio delay values for each of the unit's two inputs, which should be more than enough to cope with the specific problems encountered with different source equipment or DVD discs.
Performance
To check the DD540 out, we equipped ourselves with a trio of DVDs notorious for lip-synch problems (The Fifth Element, Seven and the first, non-special edition issue of Lock, Stock And Two Smoking Barrels), piped their pictures into a TV known to cause picture delays (Hitachi's 32PD5300, since you ask) via an extremely long video cable, and fed the digital audio stream via a very short cable into our Denon AVR-3803 AV receiver. And there was no doubt that at times, all three movies suffered with clear lip-synch problems.
Now we introduced the DD540 into the audio connection chain, headed for the trouble spots noticed on the discs previously, and tried to adjust them out with the Felston. And it worked a treat. Within seconds of tweaking the Felston's settings we'd improved matters to the point where nearly all the lip synch errors were completely sorted out, leaving us free to become properly embroiled in the show rather than distracted from it by lip-synch errors.
There are limitations to what the DD540 can do. It can't adjust the audio carried by any kind of audio connection other than a digital one, for instance. Plus it can't automatically continually vary its delay in response to the different degrees of lip-synch error that can occur at different points on a particularly poorly mastered DVD. However, generally audio delay problems caused by DVD mastering are sufficiently insignificant that they only actually become visible when joined cumulatively by other audio delay causes - such as, in our case, the TV's processing. So with the Felston on hand to remove the hardware-related delay issues, the software issues tend to become invisible.
It's important to stress here, too, that the DD540 introduces no significant reduction in sound quality. Felston claims the unit carries 'bit-perfect reproduction and re-clocking', and as far as our ears can detect, there's no reason to doubt these claims.
We guess we ought to raise questions at this point about the DD540's longevity; digital display devices are, after all, using faster picture processing with every new generation, reducing the likely impact of lip-synch issues in the future.
But you know, we carried on living with the DD540 during our day to day lives after we'd completed our dedicated tests. And even though our normal system only suffers occasional rather than continual lip-synch issues, so that we didn't find ourselves having to use the DD540 especially often. But whenever we fired up the latest DVD blockbuster it always felt strangely comforting to know that if a film-spoiling lip-synch issue did rear its ugly head, our trusty Felston would be there to sort it out…
|
A brilliantly simple little tool that affordably solves one of the modern AV world's most aggravating problems.
|
Nexsen Johnson
