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HINTS & TIPS 71

 

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SHINING EXAMPLES

Name                          Gerhard Gerbal, via email            (kcp@mweb.co.za)

Kit                               Sharp XVZ1 video projector

Problem                      Large pixels and future compatibility are the main complaints Gerhard has about his current video projector, so he has decided to get something better. He says his interest is home theatre but points out that he is on a limited budget. After doing his homework he has narrowed his choice down to two models available locally (South Africa) and asks us to arbitrate between the Philips Fellini 100 and Proscreen 4750. Specifically he wants to know are they 'HDTV 16:9' compatible and how does pixel size compare with his Sharp projector?

 

Expert Reply              The on-screen performance of both the Philips projectors Gerhard mentions should be very similar. The Fellini 100 and Proscreen 4750 have virtually identical optics, the light outputs are the same and both models use the same 1.3-inch LCD panels (there's three of them) with exactly the same number of pixels (1024 x 768). The main difference lies in the fact that the Fellini was designed principally for domestic and commercial use as a multimedia video projector whilst the 4750 has additional PC data display capabilities.  In the end it comes down to price and that points to the slightly cheaper Fellini, unless Gerhard specifically wants those PC and data display features.

 

As far as 'HDTV 16:9 compatibility' is concerned, I suspect Gerhard is getting his technical terms in a twist. These projectors will produce a standard 625-line PAL display, which is some way short of the 1200-plus lines required for high-definition TV (HDTV) operation. Both models produce a 4:3 aspect ratio display and like any normal 4:3 TV will happily show a letterboxed widescreen (16:9) image -- with black bars at the top and bottom of the screen -- though since the image is projected you won't actually see them on the screen. Nevertheless, in common with a 4:3 TV showing a widescreen picture the number of picture lines in a letterboxed image is reduced (compared with a full-screen 4:3 picture) so it won't look as sharp.

 

Gerhard should notice a big improvement in picture quality with these two. The LCD panels used in the Fellini and 4750 have more than double the number of pixels as those used in the XVZ1, so the picture looks much less grainy and the lamp almost twice as powerful as the one in his Sharp projector.

 

TV/VCR AND SATELLITE QUERIES

 

A QUESTION OF STANDARDS

Name              Mike Brame, via email                          

Kit                   Purchasing a VCR    

Problem            Mike's question appears to be quite simple, he just wants to know if we are aware of any VCRs that will replay French SECAM tapes on a PAL TV? He says he has noticed that most video recorders these days seem to be for PAL/ NTSC operation, no one mentions SECAM, but he has no interest whatsoever in VCRs with NTSC playback.       

 

Expert Reply             Hopefully an equally simple reply. The good news is that all PAL VCRs can replay SECAM tapes and that's because technically speaking there is no such thing as a SECAM VHS tape! As you may or may not know PAL and SECAM are very closely related both systems produce a 625-line picture with a 50Hz frame rate. The crucial difference that makes the two colour TV systems incompatible lie in the way colour information is processed.

 

It may well be an apocryphal story but legend has it that the French opted to go it alone when they were making the decisions about a colour TV system back in the early 1960s. They developed the SECAM system because they didn't fancy the PAL system, which was developed in Germany (remember this was only twenty or so years after WWII and feelings were still running high). The American NTSC system got the thumbs down (non merci…) because it was technically inferior and incompatible with existing television transmission systems uses throughout Europe. The story goes that SECAM is just sufficiently different to PAL to avoid infringing the patents, but we digress.

 

Faced with the problem of three largely incompatible television systems the designers of the first home video recorders figured that since the basic structure of PAL and SECAM were so similar it would make sense to standardise on the way the video and audio signals are recorded on to tape. Thus the information that ends up on the tape in a SECAM VCR is identical to that on a PAL tape. It is only when information is read off the tape that the systems diverge once again and VCRs processes the colour signals differently, according to whether they're PAL or SECAM machines.

 

MY FRIEND FLICKER

Name              N. Ready, Matlock Derbyshire                            

Kit                   Sharp DV560 DVD player 

Problem            Having recently acquired his DVD player Mr Ready says generally the performance is superb. However, he goes on to mention that after one to one and a half hours the brightness level seems to flicker up and down about six to ten times then it stabilises. Is this something to do with the player, the TV or the software, he asks? 

 

Expert Reply This is a tricky one. A faulty player is a definite possibility though it's not one they've come across before, according to the white coats at Sharp. The TV could be to blame as well, though Mr Ready didn't provide us with any details. Another candidate is a podgy SCART lead, poor connections can also cause intermittent changes in brightness, though the regularity of the fluctuations makes this a less likely suspect. If the DVD player is routed to the TV via a VCR then there is a chance that the brightness variations are being caused by the DVD player's Macrovision processor. This deliberately fiddles with the video output from the player, messing up recordings by making the brightness go up and down. Admittedly this is a bit of a stab in the dark since I would expect it to happen all of the time, rather than after an hour. However, there is an easy way to find out if Macrovision is responsible and that's to connect the DVD to the TV directly and see if it stops. If the problem persists then the chances are there's something wrong with the player, so Mr Ready should have it checked.  

 

WIDE OF THE MARK

Name              Russ, Malvern, Worcester                              

Kit                   Philips widescreen TV      

Problem            Russ recently forked out for a 28-inch Philips Widescreen TV – he doesn't say which model – and some widescreen videos on tape (Godzilla and A Bug's Life). When he played them back on his VCR (again we have no idea which one) he was surprised to find that they didn't fill the screen, leaving big black lines at the top and bottom of the picture. He says he tried all of the 16:9 settings on the TV and none of them filled the screen completely. His VCR is connected to the TV by SCART cable and he would like to know if he's wired it up properly? Russ says that he knows that not all widescreen movies are like that and he has seen videos with no bars on the screen, so what's going on?     

 

Expert Reply             It would have been helpful to know a bit more about Russ's equipment but I'll be bold and say that no, it's not a wiring problem. It's my guess that Russ is having fun and games with aspect ratios. The VHS widescreen versions of the movies Russ mentions are presented in their original theatrical format, with the increasingly popular aspect ratio of 2.35:1. That means the picture is a good deal narrower than his 16:9 TV screen, hence the black bars. However, this does mean he gets to see the whole picture, in other words no bits have been chopped off the sides. When it comes to non-widescreen versions video distributors and those involved in transferring films to tape have a number of options. The image can be panned and scanned, keeping the action in the middle of the picture. The original can be lightly letterboxed, with a little bit from the sides lopped off or in some cases the recording can be re-mastered, which is what happened with the standard 'full-screen' version of A Bugs Life. Clearly this only works on some types of material, namely cartoons and computer generated images. Pixar actually re-rendered more than half of the movie, moving objects and characters closer together to fit them into the 4:3 TV screen shape and recomputing the changes to the 'camera's' field of view. Just thought you'd like to know… 

 

SHIFTY APPEARANCE

Name              Tony Dudley, via email                          

Kit                   Panasonic TX28 TV, Sony DVD-725 DVD player 

Problem            When Tony connects his DVD player to the TVs AV1 input, using a fully wired SCART, and selecting the RGB output on the DVD he says the picture quality increases enormously but the whole image shifts about one inch to the left. He would like to know if the shift can be corrected or is this common to all DVDs and TVs?       

 

Expert Reply  No, it doesn't always happen but according to a Panasonic spokesperson it is a characteristic of some of the company's widescreen TVs and as such is counted as normal and acceptable behaviour.... Unfortunately there are no user-adjustments to counteract the displaced picture so Tony is just going to have to live with it. We would be interested to hear from anyone else who has experienced problems with this kind of set-up, particularly in light of the next letter, which also involves a Panasonic TV and Sony DVD.

 

LEAD ASTRAY

Name                          Mark Goodman, via email                                      

Kit                               Panasonic TX29 TV, Sony DVD-725 DVD player

Problem                      Mark's problem also concerns an RGB connection between a Sony DVD player and Panasonic TV. He says that he followed recommendations in HE to use an RGB connection for optimal picture quality (all true, we admit it…). The manual for his TV says quite clearly that it is RGB compatible but he says the picture is much darker than normal, with a slight smearing effect. He goes on to say that the SCART is a fully wired type but admits that it is a rather cheap one. He asks could the quality of the SCART lead have anything to do with the iffy RGB performance?

 

Expert Reply             Poor quality SCART leads, or any other kind of dodgy video lead for that matter, can have a noticeable impact on picture quality. However, the effects tend to be fairly subtle or blatantly obvious and from the description of Mark's problem it sounds as though other forces are at work, causing the reduction in performance. We passed on the query on to Panasonic's technical bods and they suggested that the problem either lay with the DVD player or it might be due to a fault on the TV, in other words they didn't know. The simple way to find out what is responsible is for Mark to connect his DVD to a friend's TV (one with RGB input and preferably not a Panasonic model) and see what happens. If the picture looks okay the problem definitely lies with the TV. If the picture still looks bad then he should substitute the SCART lead. If that cures it then his cable is faulty, if not it’s the player.

 

BOX COPY 1

GETTING STARTED

Sony started it with the Wega tube and now just about every TV manufacturer has at least one, and usually several models with a 'super flat' picture tube, so what's all the fuss about? The main technical benefit of a flat faceplate is reduced reflections, from overhead lighting and windows etc., but there's a lot more to it than that. Flat screens are aesthetically pleasing and they give manufacturers something to boast about. The use of the word 'flat' also carries the underlying suggestion of a flat hang on the wall TV screen, though don't try it with any of these sets… It's a feature that customers can easily relate to and doesn't involve salespeople spouting meaningless technical gobbledegook.

 

The obvious question is why didn’t manufacturers do it years ago? Doubtless they would have, if they could, but it's surprisingly difficult. The problem has been getting even brightness and sharp focus across the width of the screen, especially at the edges, and it's even harder with flat 16:9 tubes. That's because the electron beam strikes the edges of the screen at a sharp angle, resulting in a oval, rather than round spot, so all kinds of technical tricks have to be used to make sure it doesn't happen. Flat screens also cause difficulties with strength and safety. Curved faceplates are much stronger and better able to resist implosion, if the screen is hit with a sharp heavy object. The only way to maintain the strength on a flat faceplate is to use thicker glass, and that means these tubes can be a fair bit heavier than their conventionally curved counterparts.

 

LD AND DVD QUERIES

 

STAR LETTER

 

STALLING FOR TIME

Name              Leo Lawless, via email  (Leo.Lawless@Datapackaging.com)         

Kit                   Panasonic Tau TV, Sony 725 DVD player   

Problem            He is generally impressed with the picture and sound quality of his set-up but Leo complains that on a number of DVDs there seems to be a momentary 'stall' on playback. He cites several examples, including Blade, Godzilla and Lost in Space. 'Am I being naive' he asks, 'I expected to be able to watch a DVD movie without these imperfections'. Leo wants to know if the problem lies with the disc or his Sony player?           

 

Expert Reply             The momentary glitch Leo is seeing is caused by our old friend layer change. Basically what happens is this.  In order to squeeze a full length movie and all the extras onto one side of a DVD the information has to be stored in two separate layers, one on top of the other. (In fact up to four layers are possible, but that's for the future). The uppermost layer is read first, on a spiral track running from the centre of the disc to the rim, then the laser pickup re-focuses onto the second layer and starts tracking inwards on a reverse spiral, back to the middle. The changeover from layer 1 to layer 2 takes a finite time, some machines do it faster than others, and in general newer players are quicker than older ones. Some early models took a couple of seconds; most recent machines do it in less than half a second.

 

It's a bit optimistic to expect perfection from a new and evolving technology DVD has had its fair share of bugs but thankfully most of the really bad ones have now been sorted, which isn't bad going in less than two years. If you think back to the early days of VHS remember how long it took manufacturers to achieve half decent picture quality, get around to trick play facilities, develop simple to use timers, and don't forget remote controls were an optional extra for the first five years! The bottom line is there is usually a penalty to be paid for being an early adopter and DVD is no exception but in the scheme of things the interruption due to layer change is not a big deal and we have no doubt that it will eventually disappear.

 

ZOOM WITH A VIEW

Name              Mark Rylance, via email                          

Kit                   Nokia 7296 TV, Sony DVP-S715 DVD     

Problem            Having had his DVD player for some time Mark is now considering a Region 1 upgrade. However, in the past when playing NTSC discs he noticed that one of the zoom modes (full size/correct aspect ratio) was unavailable. He would like to know if Region 1 NTSC discs have the same limitation? Secondly, he wants to know if he can get DTS through the optical digital connection on his player.      

 

Expert Reply             In a word yes. The DVD player's zoom facilities are determined by the makeup of the picture signals, which do not vary with regional coding. The data flags responsible for Regional coding are embedded in the disc and tell the player whether or not it is allowed (or able) to play the disc. As far as I am aware the UK version of the S715 didn't have a DTS enabled digital output though it is possible some later models might have had this feature, if so you should see a DTS logo on the front and you'll be able to use an optical connection to the amp/processor.

           

COORS MELTDOWN

Name              Michael Goundry, via email                                                        

Kit                   Panasonic DVD, Panasonic TX47PT1 TV, Yamaha DSP E924 AV amp/processor          

Problem                      So far Michael has tried three different copies of The Coors, Live at the Albert Hall on his DVD player – all brought from HMV -- and they all suffer from the same problem, namely they don't appear to play in 5.1 surround sound on his system. He says that the problem is that dialogue doesn't come through the centre channel but is heard on the front stereo speakers, there also seems to be rather a lot of bass coming from the dialogue channel, which doesn't sound right. The disc is double-sided and one side is clearly marked as having a Dolby Digital soundtrack, and this information also appears on the packaging. He wants to know if this is a known problem, or is there something wrong with his ears?

 

Expert Reply  Warner Vision, who distribute the DVD in the UK say they're not aware of any batch problems with this disc but a spokesperson was at pains to point out that the recording was re-mixed and encoded for Dolby Digital according to 'artistic considerations'. I take that to mean that someone decided to have particular sounds on particular channels, so maybe it is meant to sound that way…  I haven't come across any other complaints on the usual DVD gripe sites on the Internet and Michael says it sounds the same on a friend's set-up. This sems as though it has to do with Michael's perception of how the concert should have sounded, rather than a hardware problem, and that is well out of my jurisdiction, so we'll move swiftly on.

 

GETTING A BUZZ

Name              Richard Dixon, via email                          

Kit                   Pioneer 717 DVD player 

Problem            Richard says he is very pleased with his DVD player but wants to know if we, or anyone else has experienced a 'buzzing vibration' from this machine when it is working. He adds that he's sure it's not his imagination…

 

Expert Reply             The deck mechanisms in most DVD players emit some low level motor noise and generate a certain amount of vibration but it is usually not enough to be concerned about as it will be drowned out by the soundtrack. Nevertheless we always listen closely to the players we test, just in case. When we reviewed the DV-717 earlier in the year our sample got a clean bill of health as far as noise and vibration were concerned but that's not to say Richard's one is as quiet as ours; there could be something wobbling around inside or it could be badly aligned. There's another possibility and that is the surface or shelf on which it is standing is not perfectly flat or it is causing it to resonate and act as sounding board, amplifying the noise. Richard should try placing the player on the floor or standing it on something that will dampen out the vibration. If that doesn't do the trick, or the buzzing can be heard over the soundtrack at normal listening levels then something is plainly wrong and it needs to be investigated on the bench.             

 

CODE BREAKER

Name              Eddie Scott, via email                                                  

Kit                   Samsung DVD-807 DVD player Toshiba DPL TV      

Problem            Eddie says that he was one of the first to buy the Samsung DVD-807 players. He reckons that he was so early that he got to his local branch of Woolworths just as the guy was stacking them on the shelves, and this was before any of the magazines had reviewed it. Yes, well done Eddie... And so to his other problem. To celebrate his good fortune Eddie brought Region 1 copies of Kick Boxer and Broken Arrow, but he cannot get the machine's Region 1 modification to work. He goes on to say that the code numbers he has tried are 119 and 200, but nothing happens!        

 

Expert Reply             In case you missed the story, the Samsung DVD-807 was the result of an exclusive deal between Samsung in Korea and the Kingfisher Group. The 807 was sold for the then astonishingly low price of £249 and that included bundled DVDs. Word spread quickly that the 807 could be modified for all region playback using a simple code, entered into the remote handset. Not surprisingly the whole batch sold out within a few days and that is why it was never reviewed it in HE. By mid April you couldn't get hold of one for love nor money. Samsung and Kingfisher never repeated the deal and all of the Samsung's machines now in the shops are ostensibly Region 2 machines, brought in by Samsung's UK division.

 

Now to Eddie's query. Normally we wouldn't countenance this kind of irresponsible behaviour and we feel it is our duty to remind owners of DVD players of the perils of tinkering with their equipment. However, in this case we'll make an exception since the information is in the public domain, and it does no harm to the machine.

 

Eddie has got it almost right but there is a bit of a trick to enabling all region playback. First make sure DVD mode is selected on the handset then load a Region 1 disc. Next remove the disc, close the drawer and press Time Search, followed by numbers 119 on the remote keypad. Finally, put the R1 disc back in the tray and press the play button. If for any reason you want to restore the machine to Region 2 operation follow the same steps but this time use the code 911. Incidentally, keep it to yourself but this trick should also work with the DVD-907, but not, as far as we know, any other Samsung machines.

 

BOX COPY 1

GETTING STARTED

Do leads make a difference? Audio connecting leads generate fierce debate amongst hi-fi aficionados and there are plenty of people willing to pay extraordinary prices for exotic cables on the basis that they can make an audible difference to sound quality. This begs the question why hasn't there been the same sort of interest in higher-quality connecting leads in video circles? The truth is video cables and connectors do have an impact on picture quality, but our eyes are not very good at detecting relatively small changes in picture quality. Differences do show up on static test patterns – when you know what you are looking for – but they can be very hard to spot on a moving picture. There's an added difficulty that unlike a favourite piece of music, which you'll probably listen to many times, we're unlikely to watch a recording of a movie or TV programme more than a couple of times. That means we're less likely to have a benchmark or reference with which to compare the before and after effects of changing a set of leads.

 

So does that mean it's not worth spending a few more pounds on good quality AV leads? Not a bit of it, whilst the improvements in picture quality may not be very easy to see they are there and every little bit helps. Quality leads have other advantages over the cheapo cables supplied with many AV products. The conductors are generally a made to a tighter specification and more often than not, gold plated which means they're less likely to suffer from intermittency problems, or degrade over time. The standard of manufacture is generally a lot better too so they should last longer and able to withstand repeated plugging and unplugging.

 

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Ó R. Maybury 1999 1409

 

 

 

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