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Name                          Mark Davies, via e-mail    

Kit                               Philips ON Digital set-top receiver

Problem                      Fired by our digital TV reports Mark brought a Philips ON Digital decoder box from a local TV dealer. When the shop called ON to get the box registered they asked for his postcode, he was then told that not only did his postcode not exist, but that the digital signal was not receivable in Barnet, North London, where he lives. Mark persuaded the dealer to let him have the box at the discounted price of £199, on the understanding that if he could get a signal he would return and sign the contract. Sure enough it didn't work, so Mark had a new aerial and booster fitted, at a cost of £300, got a signal and called ON Digital who reluctantly agreed to switch on his decoder but said they wouldn't give him a refund if it didn't work properly. Now he has entered the digital age Mark says he seems to have taken a step backwards. The sound is awful with no surround information, the picture breaks up or freezes and it is worst on Film Four, which he particularly wanted to have. He wants to know how some channels can be so much better than others when they come from the same transmitter?


Expert Reply             Mark should have taken heed of the warnings. The Barnet area is out of range of the Crystal Palace transmitter and the local relay is not due to be upgraded for some time, (the BBC couldn't say exactly when, but told us it would be 'months rather than years'…). The picture and sound problems he describes are a textbook example of a weak digital signal. Unlike a poor analogue signal, where the picture degrades slowly, becoming noisier but staying watchable, a digital picture deteriorates in a different way. As long as some data is getting through the decoder has a stab at generating a picture (and sound), and it can look quite good, with little noise -- which we tend to notice  -- and artefacts (colour blocking, freezing and so on), that our eyes are more tolerant of. The number of picture faults from a weak signal depends on the data rate. Film Four is using a higher data rate, compared with the other channels. Consequently the decoder is finding it harder to keep up with the errors caused by the weaker signal and so it makes more mistakes. Before you go digital check first with the BBC Reception Advice line (0870 010 0123) or ON Digital (0870 600 5656).





Name                          Kevin            A. Jones, Merton Park, London SW19            

Kit                               Panasonic TX-29AD1DP TV, JVC HR-S9500 S-VHS VCR, Pioneer 606 DVD, Pioneer 925 Laserdisc, Yamaha DSP A592 AV amp

Problem                      Everything in Kevin's system is working fine, except for one niggling distraction. It only happens on some pre-recorded VHS tapes when the soundtrack is relatively quiet. He can hear a slight humming sound in the background, which disappears when the sound comes back up. It only affects some tapes, DVDs and Laserdiscs are clear. He has tried changing the connecting leads but the problem persists.


Expert Reply             The clue to Kevin's problem is the fact that it only happens on a minority of pre-recorded tapes. The most likely explanation is the tapes concerned have a minor tracking or processing error that the VCR cannot resolve, or they are simply bad copies, with the sound he's hearing, actually recorded on the soundtrack. It's worth playing the tapes on another machine, if the sound disappears mis-tracking is the prime suspect. 



Name                          Neil Pattison, via e-mail             

Kit                               Sharp XV20E video projector, Pioneer 505 DVD player   

Problem                      Following a determined effort to track down a Sharp dealer in his area (Neil lives near Newcastle upon Tyne), he finally brought his projector mail order (he admits doing this after reading our lukewarm review…). Unfortunately the first one blew up but it was replaced; now he has noticed that the picture on Region 1 DVDs (in pan and scan format), 'bend' severely to the right at the top of the picture. This doesn't happen with PAL discs or off-air video. He has tried another DVD player and different connections but with the same result. The bend is not apparent when the DVDs are played on his Philips TV, so what is going on?


Expert Reply             Although our test report didn't mention DVD and NTSC replay were not very impressed with the image quality on this model, Neil really should pay heed to reviews… The bendy picture he describes sounds very much like 'tearing'. This can be caused by anti-copying systems like Macrovision which deliberately spoil the signal making it hard or impossible to record on a VCR, (though it is sufficiently intact for a TV to display a watchable picture). In Neil's case it sounds as though the projector is having difficulty locking on to the copy-protected NTSC signal coming from the DVD player. Macrovision can be disabled on some players, but he would have to seek expert advice on this matter, the Techtronics web site (www.techtronics.com), might be a good place to start.



Name              Glyn Hughes, via e-mail                            

Kit                   Panasonic NV-HS950 S-VHS VCR  

Problem            Having sold his Sony SLV-E80 video recorder to buy the Panasonic Super VHS machine. Glyn is not a happy man. In fact he has just taken the second VCR back for a refund. He says that pre-recorded tapes exhibit an excessively high level of grain, TV programmes recorded on S-VHS actually look worse than tapes made on the VHS machine he just sold. Both Super VHS VCRs were the same, he is getting a good TV signal and he uses TDK tapes. Now he's left without a VCR and wondering if S-VHS is all it's cracked up to be?        


Expert Reply             In all of the reviews we've carried on S-VHS video recorders we have stressed that recordings of off-air TV signals do not look significantly better than those made on ordinary VHS video recorders. S-VHS VCRs come into their own when used for editing home video movie footage shot on Hi8, S-VHS-C or digital camcorders. In other words, don't buy an S-VHS video recorder and expect to see a big improvement the quality of off-air recordings; for a more detailed explanation see this month's Getting Started. We're a little surprised that existing VHS tapes look worse on the Panasonic VCR. It could be that Glyn's old Sony machine was producing a slightly 'soft' picture, that masked the noise and grain which the S-VHS deck is now showing up so clearly.



Name                          John Lawrence, Calne, Wilts                           

Kit                               Toshiba 32MW7DB

Problem                      After reading our review of the Toshiba 32MW7DB John went out and brought one from a well-known dealer in Bolton. When it arrived there had been some damage in transit but he accepted delivery, even though there was no receipt with the set. It all seemed to be okay but shortly afterwards it began to 'lock up', it was impossible to change channels and the picture curves to the right. He phoned the company twice and they said they would ring back -- but nothing happened. He wrote to them but not a peep. He says that none of the problems are serious, do we have any ideas? 


Expert Reply             Yes we do! John should not be writing to us, this set is brand new, still under guarantee and he has a right to demand that it be fixed forthwith. The fact that he doesn't have a receipt is neither here not there. He should write to the company, giving them a clear deadline by which they should repair the TV or refund his money otherwise he will begin legal proceedings. Of course, none of this would have happened if John had refused delivery without the correct paperwork or returned the set immediately he realised that it had been damaged in transit -- a lesson for us all! It also helps to pay for such purchases with a credit card, as card companies will help to recover your money if the deal goes belly up. 



Name                          Dav Alderson, via e-mail             

Kit                               Pioneer 50-inch projection TV

Problem                      The latest clamp down on TV licensing has been widely reported and Dav wants to know if it is true that the detector vans pick up magnetic fields generated by the cathode ray gun picture tube? If so, he wants to know, is it possible for detectors to pick up video projectors and what about plasma screens? He adds that he is fully paid up and this is purely a rhetorical question…


Expert Reply             The TV licensing people assume that every UK household has a TV set, and they're probably not far wrong. They target the addresses without a licence using their enormous computer called Lassy (Licence Administrative Support System), said to have the largest and most up to date address database in the land. On average they find and prosecute around 400,000 licence dodgers every year. TV Licensing repeatedly send out demands to non-licensed households, (much to the annoyance of those very few people who do not have a TV!). If they don't cough up they send round the boys in the van (there are more than 600 Inquiry Officers with sweeping, police-like powers, they administer hundreds of search warrants each year! The vans have a very sensitive receiver coupled to a highly directional aerial that can pick up the RF signal generated by the line oscillator and deflection coils around the neck of the picture tube. The signal varies according to the TV program being received so they can also tell what channel is being watched. The house is photographed and the data logged for evidential purposes. People living in flats might think they are safe from the detector vans though nowadays they use portable detectors.


LCD projectors and plasma screens and laptops PCs with TV tuner cards do not have emit any significant RF radiation so they cannot be seen by detector vans.  However, we doubt that many people would be daft or desperate enough to splash out several thousand pounds on this kind of technology, simply to evade the licence fee. Persistent dodgers who deny they have a TV can expect a knock on their front doors, often around mid-evening; the strains of Coronation Street or East Enders coming from the living room is a dead give-away…




If Super VHS is so great, why do recordings of TV programmes look no sharper than those made on ordinary VCRs? Part of the answer is due to the fact analogue TV channels are broadcast as 'composite' video signals, with the brightness (luminance or 'Y'), and colour (chrominance or 'C') components bundled together. All VHS VCRs break the signal down into its constituent parts during the recording process. This is quite a complicated business involving re-modulation and frequency shifting, all of which introduces extra noise into the picture signal. Ordinary VHS machines recombine the chrominance and luminance signals during replay but a lot of the extra noise disappears or is discarded because it is outside the frequency range of the system. On S-VHS recorders the Y and C signals remain apart until they are recombined into the displayed image on the screen. S-VHS has a wider bandwidth than ordinary VHS, so it captures more detail, and that includes extra high frequency noise. When we look at a video picture one of the first things we are aware of is the amount of grain or noise. Fine detail is a high frequency component in a video signal, but it tends to be masked by noise. Recordings made on S-VHS/S-VHS-C or Hi8 camcorders go through fewer stages of processing, which means less noise and a cleaner-looking picture 







Name                          Peter Richardson                

Kit                               Sony KV28WS TV, Kenwood KR-V6060 AV amp, Panasonic DVD-A110 Region 1 player, Pioneer CLD 1850

Problem                      Having just imported a DVD player from the US Peter has discovered, to his considerable annoyance, that there is a serious lack of bass, compared with his old laserdisc player. He has brought a number of discs, including Godzilla and Lost in Space, he says the picture quality is fantastic but the sound lacks the 'punch' that his LD set-up can deliver. Peter has read a number of reviews of the Panasonic machine and all were favourable, he has checked all the connections, which were the same as those used on the LD player, so what has gone wrong?


Expert Reply             There's probably nothing wrong with Peter's system, it is an accepted fact that Dolby Surround soundtracks often sound better on laserdisc. The audio characteristics and dynamics of DVD are quite different to those of laserdisc (see Getting Started). DVD audio tracks are configured to carry Dolby Digital/AC-3 and or MPEG 2 5.1 channel surround sound, where bass is carried on a separate discrete channel called the 'LFE' (low frequency effects). DVD players convert or 'downmix' the Dolby Digital soundtracks to a 'mixed' stereo output containing Dolby Surround information, the processing may not include the LFE channel. That coupled with the losses caused by the compression systems used to encode the data reduces the dynamic range and consequently limits bass content on Dolby Surround soundtracks. The bass Peter is looking for is almost certainly there but he will need to invest in a Dolby Digital decoder/Amp and sub-woofer to get the full whack.  



Name                          Kane Williams, Branksome, Poole                          

Kit                               Sony KV32WF1TV, Panasonic A310 DVD player 

Problem                      Whilst on holiday in Spain recently Kane says that he noticed that a reflected image of a TV picture in a mirror seemed to improve the quality with less grain and richer colours. He wants to know why, and wonders if this technique can be applied to TV sets? However, his main question concerns blurring on DVD replay, especially noticeable in Contact -- he says the scene where Jodie Foster and Matthew McConaughey talk under the stars it looks more like a meteor shower! Secondly, he asks why there is at least two inches cut from the left side of the picture in movies like Starship Trooper. He points out that a movie shot in an aspect ratio of 1.85:1 fills the screen on his 16:9 TV when in fact there should be bars at the top and bottom of the screen. Kane wants to know if he can get into the TV's factory presets and change the settings.


Expert Reply             Kane's mirror observation is interesting and it does appear to work but we don't think there's any magic involved. When you see a reflected image of a TV screen in a mirror, you're seeing the screen at a distance, thus lessening the impact of line structure and noise. The reflected picture is smaller so it looks 'cleaner'. If anyone has a better explanation please let us know.


Bright objects against dark backgrounds have been known to upset TVs with 100Hz displays but that doesn't apply to Kane's Sony TV. When we reviewed this set last year we commented on the fact that picture quality was a bit ordinary and that colour fidelity was not that wonderful, if possible Kane should try his player on another large screen TV to see if it's the TV or not. If the effect is really that noticeable it's worth changing the disc or having the player looked at.


As far as aspect ratios are concerned, fiddling with the TV's internal display settings  -- even if it were possible -- probably wouldn't help. It is the film company that decides what shape/format picture ends up on the disc, and what, if anything is going to get chopped, but whatever they do is going to upset someone. Owners of 4:3 TVs are driven potty by letterboxed widescreen transfers and 16:9 TV owners hate the cropping that occurs on panned and scanned movies.



Name                          Jason Sheen, via e-mail                                        

Kit                               Sony 715 DVD player, Sony KV-32FD1 TV      

Problem                      Jason is having problems with seven of the twenty or so DVDs he has purchased so far. When anything moves on the screen a 'trail' is left, faces have a ghost-like quality. He says it is most noticeable on One Flew Over the Cuckoo Nest, Dusk Till Dawn, Unforgiven, the Right Stuff and Batman. He doesn't think it’s the discs as he has tried another copy of Cuckoo's Nest, with the same result. Is it the TV or the DVD player?


Expert Reply             The 715 has come in for a fair amount of stick and the recent admission by Sony that there's a firmware problem that can only be resolved by a chip-swap hasn't helped. However, in this case the blame may just lie with the TV. This model has a 100Hz display and extensive digital processing systems. In last year's test report we did mention that rapid motion could cause digital artefacts, of the type he describes but the only way for Jason to isolate the cause is to hook his player up to another (preferably non-Sony) TV, and see what happens. If anyone else has experienced problems with the titles mentioned, or any other movies for that matter, on other TV/DVD combinations we would like to hear about it, and if possible include the time(s) the effect occurs.   



Name              S. Bennett, Brighton, Sussex                                   

Kit                   Pioneer CLD-D780 laserdisc player, Toshiba SD-3006 DVD     

Problem            The LD and DVD players have been in use for almost a year with no problems, says Mr Bennett but he recently brought a new album on CD by Richard Thomas called Mirror Blue, on the Capitol label. Neither the LD or CD player would recognise the disc but it played perfectly on an old mini hi-fi system. He has tried other CDs from other companies but only this one seems to be affected, so he wants to know if there are any other audio CDs that he should avoid?            


Expert Reply              It seems likely that this is a one-off. DVD players do appear to be less tolerant to faults or imperfections on audio CDs than most hi-fis though it is unusual for a laserdisc player to behave in this manner. We are not aware of any compatibility issues with this or any other titles from Capitol Records and an Internet search drew a blank. As usual, any reader feedback on this matter will be appreciated.   



Name                          John Nesbit, Southampton             

Kit                               Toshiba 33227DB TV Panasonic NV-HD610 VCR, Pioneer CLD-925 laserdisc player, Pioneer DVL-909 DVD player

Problem                      John is generally very pleased with the performance of his system but he has a problem during movie playback on some discs where the brightness sometimes drops by between 5 to 10% for a couple of seconds. The same thing sometimes occurs on the Panasonic VCR when replaying rented tapes. The dealer says this is a feature on some tapes and discs, to prevent copying. He wants to know if this is correct or could it be something to do with the Pioneer player?


Expert Reply             Fluctuations in brightness are symptomatic of copy protection measures but it should only show up on recordings made from pre-recorded movies. Since John is having trouble with both tapes and discs it might be that the TV is being unduly sensitive, it's definitely worth having it checked.



Name                          Eoin Nolan, via e-mail

Kit                               Panasonic DVD-A450EN DVD player

Problem                      Eoin lives in Singapore and says he's an avid reader of HE -- we obviously reach the parts other mags, etc. etc. … -- anyway, Singapore is Region 3 and Eoin reckons software availability is even worse than Europe and it's much more expensive. He's tried to get hold of Panasonic DVD-A350 for upgrading to multi-region playback but the closest he could get is the Region 3 DVD-A450 which has a very similar spec but has different sockets (no SCARTs and no MPEG2 audio decoder). He wants to know if it is possible to convert this player to Region 1 and 2 playback, and whether the lack of an MPEG 2 decoder is going to be a disadvantage?


Expert Reply             Although we can't be 100% certain we suspect the A450 is indeed very similar to the A350 and that one or more of the multi-region modifications will work on this machine. It's worth Eoin asking around, posting a query in one of the many Internet user/news groups would be a good place to start, or e-mailing one of the companies selling modification kits. He will find literally hundreds of interesting sites -- probably quite a few local ones -- by simply using DVD and Regional Coding as key words on any of the search engines. He needn't worry about not having SCART sockets on his player, they are only useful if you live in Europe and all of your other AV components have them; there are plenty of people who wish we didn't have them… As to whether he will need MPEG 2 audio, the simple answer is no. It is possible that a few PAL discs will have MPEG audio soundtracks but all players will have a mixed audio output as well, containing Dolby Surround information, so there's no problem with compatibility. Most people seem perfectly content with Dolby Digital/AC-3 sound and that is likely to become the de-facto standard -- if it hasn't already -- for DVD surround. The A450 is listed as having a DTS bitsteam and we count that as far more useful.




The sound system on DVD causes a lot of confusion, indeed sometimes we have trouble keeping up with all the developments… Anyway, here are the basic facts, and please be aware we're only talking about bog-standard DVD-Video.


Discs can have up to 8 tracks or 'streams', on PAL Region 2 discs they can each be used in one of three ways. The most familiar audio format is LPCM  (linear pulse code modulation), it is part of the core specification for players and essentially the same coding scheme (with a few extra bells and whistles) that is used on audio CDs. That is why all DVD decks can also play audio CDs. Because nothing is added, or taken away -- i.e. the data is not compressed -- it is known as a 'lossless' system.


The most interesting audio format -- from the home cinema perspective -- is Dolby Digital or AC-3. This is a compressed or 'lossy' multi-channel coding system; it can be used in a variety of ways but the commonest arrangement is the so-called 5.1 configuration, with 5 full bandwidth channels (right and left stereo, centre front and stereo rear effects), plus one low frequency effects (LFE) channel.


The third system, peculiar to Region 2, is MPEG 2 audio. This is another lossy multi-channel system with the same 5.1 channel layout. Its inclusion in the spec was mostly for political reasons, the bottom line is that there are no significant performance benefits -- compared with Dolby Digital -- nor are there likely to be many discs with only MPEG 2 soundtracks. Not that it would be a problem because it is now a stipulation that all Region 2 players must be able to read all three audio formats.


There is also provision in the international specifications for two other sound systems: DTS (Digital Theatre System), and SDDS (Sony Dynamic Digital Sound). Both are high-quality multi-channel systems originally developed for theatrical use. There is no requirement for manufacturers to incorporate DTS or SDDS decoders in players, though some decks sold in the US have dedicated outputs suitable for connection to external decoders.



Ó R. Maybury 1999 0202



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