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HINTS & TIPS HE 106

 

Name                Andrew Fordham

Kit                    buying top end home cinema kit

Problem            In HE 104, you mention that NTSC signals look best through a component connection but that PAL signals are (albeit marginally) better through S-Video than component.  Could you explain why this might be?  I'm about to buy a component compatible display, and want to ensure I'm getting the best out of everything.

 

Reply

In fact the best connection option for PAL equipment is RGB but that particular option wasn’t available in the query you’re referring to. Technically RGB is a ‘component’ video signal format but these days it usually refers to the ‘Y’PbPr’ colour difference connection, also known as ColourStream. This type of connection is popular in the US but is only available on a handful of home cinema TVs and DVD players sold in this country.

 

RGB and Component video are not that different but Component video connections are more widely used on professional and broadcast video equipment as the high-frequency colour information in the video signal is less susceptible to instability and ‘phase errors’ as it passes through cables and connections and various stages of processing. It just so happens that the NTSC colour TV system is more prone to colour instability in fact engineers still joke that NTSC stands for ‘never twice the same colour’ (it actually stands for National Television Standard Committee). PAL colour signals on the other hand are a lot more robust and can be more easily transported using the slightly simpler RGB signal format. The bottom line is that Region 1 NTSC DVDs look their best when shown on NTSC equipment with component video connections and PAL region 2 discs should be viewed on PAL equipment using RGB connections. However, if you want to play an NTSC R1 disc on your PAL setup, or a PAL R2 disc on your NTSC system extra layers of processing and signals conversion have to come into play, which one way or another will degrade the signal.

 

QUICK TIP

If you think three (or four) video connection systems is confusing here’s something else to think about. Several attempts have been made to introduce a digital AV connection on DVD players, using the IEEE 1394 or ‘FireWire’ system, which is already used to connect digital camcorders to PCs. A digital AV connection would theoretically give even better picture quality but it would require a new breed of TVs with on-board digital decoders moreover the DVD industry is worried that fitting FireWire sockets to DVD players might encourage piracy, so don’t hold your breath...

 

 

 

Name                Mr C. Sutherland, Edinburgh

Kit                    Philips widescreen TV

Problem            I have had two Philips widescreen TV's over the last 6 years, the first developed an inward concave appearance at either side of the screen and widescreen functionality failed after only a few days. This was replaced

under warranty, unfortunately however, the replacement – now out of warranty – is doing exactly the same. Is this a problem common to Philips, if so how is it cured and more importantly how much do you recon will it cost?

 

Reply

It sounds a lot like ‘barrel’ distortion. The geometry of the picture on a CRT is controlled by modifying the shape of waveforms driving the ‘deflection’ coils mounted on the neck of the picture tube. Occasionally the circuits that control these waveforms fail but more often than not the change in picture shape is down to component ageing, normally minor changes are compensated for but if it goes too far off bonk, it can be bought back into line using controls on the TV’s hidden service menu. It’s the sort of thing a competent engineer should be able to fix in five minutes flat. However, if a fault has developed then it will take a lot longer and may involve a board change, racking up the labour and parts costs. Unfortunately it’s not something you can tackle yourself. All we can say is that Philips TVs are no worse than average when it comes to reliability and picture geometry problems, so you have probably just been unlucky. The chances are it is only misalignment but do get an estimate from at least a couple of local firms.

 

QUICK TIP

There are several common picture geometry faults, most of which are caused by the ageing of the picture tube and drive electronics. The opposite of barrel distortion is known as ‘pincushion’ distortion, that is when the edges of the display curve inwards, towards the centre of the screen. Trapezoid distortion happens when the picture is slanted to the left or right. Most picture geometry faults are easily cured by an engineer using the TV’s setup controls but if the picture shape keeps changing it could be a sign of something more serious.

 

 

 

 

Name                Steve Jones

Kit                    Limit 8072 DVD player

Problem            I have been buying a series of music DVD-Rs from a guy in America and most play without trouble on my computer. However, most of them would not play on a DVD player (Limit 8072) and coloured squares and rectangles appear on the screen and occasionally this affected the sound. I’ve had various suggestions: change the setting from PAL to NTSC; the machine must be faulty; the discs must be faulty, etc. However, a second Limit 8072 had the same problem yet they all play perfectly on a friend’s Panasonic RV3. I have since given up and accepted a credit note!

 

Reply

DVD-R is the record–only variant of the DVD-RAM format, the recording format officially sanctioned by the DVD forum, the organisation that controls DVD technical standards. However, although in theory DVD-Rs should play on most ordinary DVD players, it’s not part of the spec. That’s because DVD-R discs are made by a quite different process to regular mass-produced DVDs and have slightly different optical characteristics  (basically the reflective ‘pits’ that represent digital data are not as shiny). If the data cannot be reliably read from the disc you end up with those coloured blocks and rectangles, as the processing circuitry in the player struggles to make sense of the fragmented datastream. There could be several reasons why this is happening, the most likely ones being a problem with the laser pickup, but it’s quite possible that the player is simply not capable of playing DVD-Rs. Comparatively few manufacturers even mention of it, indicating that the jury is still out over the future of DVD recording. However since Panasonic is one of the few companies marketing a DVD-RAM video recorder so you can take it as read that they have made it their business to make their DVD players DVD-RAM/DVD-R compatible.

 

 

QUICK TIP

DVD-R is a variant of the DVD-RAM format. Files can be added to the disc by the recording machine, up to its maximum capacity, but discs cannot be played on regular DVD players until they are ‘finalised’, at which point no more recordings can be added, nor can the data on the disc be erased. This was seen as a major limitation for a DVD recorder, which backers of the rival DVD+RW and DVD-RW formats seek to address, in both cases discs can be used like tape (i.e. watched and wiped), but like DVD-R, there are compatibility problems with existing players.

 

 

 

 

Name                Alasdair Urquhart

Kit                    Toshiba SD-220 DVD player

Problem            I’ve just bought a Toshiba SD 220E DVD player. After watching The Matrix I realised that there seemed to be a scene missing. I checked the running time and found that I was missing eight minutes! I have tracked the missing time to the big shoot out scenes where Neo and Trinity rescue Morpheus. I know there were problems with the Matrix DVD when it came out and wondered if this could be a manufacturing fault? I used to be able to play this scene OK on my old but busted player....

 

Reply   

Compatibility problems are due to a variety of factors, including poorly authored discs, damaged discs and firmware problems in the player, of which Toshiba players have had more than their share. You should contact the dealer to make sure that there are no firmware upgrades for your model. However, reading between the lines you seem to really like this scene in The Matrix and that may provide a clue. A slight warp in the disc or misalignment of the laser in your old player, or its servo mechanism can sometimes result in the two coming into contact. Even a spec of dirt is enough to cause a microscopic scratch on the surface of the disc. Normally it doesn’t matter, but if that same scene is played back over and again eventually the scratching could cause the player to skip that segment. Hold the disc up to the light and move it around and look for fine banding on the surface. If so you might be able to remove it with a mildly abrasive disc polishing compound. It’s even possible to remove quite serious scratches in CDs and DVDs with this stuff, which is available from all good video and audio stores. Don’t tell anyone, but Brasso also works really well, especially on badly scratched Playstation 1 discs, but you try it at your own risk…

 

QUICK TIP

Although the DVD spec was finalised over five years ago it is still a work in progress with new features and facilities popping up that occasionally cause compatibility problems. News of badly mastered discs may take several days or even weeks to come to light, so it’s worth checking, before you rush out and buy the latest blockbuster. Just type the name of the movie, and the words ‘DVD problem’ into the Find field of your favourite Search engine, or for some advance warning pay a visit to http://www.dvdreview.com/movies/FilmVault.html, for a up to date list of tricky discs from Region 1.

 

 

 

Name                D.T.

Kit                    buying AV system

Problem            I’m looking for some help in choosing components for my first AV system in my bedroom (1.75m square). So far I have a Marantz SR5200 amplifier and I like the look of the B&W 602 S3 main speakers and Phillips Q50 DVD player. I'll be mostly using the DVD player to listen to music (rock and dance).

 

Reply

With a relatively small room, and bearing in mind the fact that space is usually at a premium, we usually suggest fairly modestly sized components, or even an all-in one mini-system but since you have already plumped for a chunky amp and are a self-confessed rock and dance music fan we must assume that the normal considerations do not apply. The B&W speakers and your amp should go well together and when the time comes to upgrade to full-blown surround you can keep it in the family with a pair of B&W DM600S3’s for the rears, and LCR60 S3 for the centre and an ASW600 sub, which should work really well in that kind of space. The Philips DVD-Q50 is fairly well specified with an on-board Dolby Digital decoder and a selection of the usual toys and gadgets though with a street price of around £350 the value for money rating is rather average and in any case you don’t need the Dolby decoder as you’ve already got one in your amplifier.

 

You might want to have a look at a couple of recent entry-level machines from Sony and Toshiba (see this month’s Group Test), now selling for around £200, they compare very well with the Philips machine in terms of picture quality and may even have a slight edge with audio CD replay.

 

 

 

Name                Michael Magro

Kit                    Denon AVC-2800 Pro-Logic Amp, Mission 735 Main Speakers, B&W CC6 Centre and MS 10i rear speakers

Problem            I want to upgrade to Dolby Digital and DTS sound and wish to keep my current amp and add a processor. I was considering the Yamaha DSP-E800 Processor/Amplifier to power the centre and rear channels and keep my Denon to power the main speakers but the DSP-E800

doesn't include Dolby Pro-Logic ll and Dolby Digital ES and DTS ES. Do

you know of any processors that have all this?

 

Reply

How serious are you about hanging on to that Denon amp? Whilst you can almost certainly cobble something together with what you have, and some external components, you will probably end up spending a great deal more than the cost of simply replacing the amp with one that has all of the advanced surround sound features and Pro Logic II (see Getting Started) that you are looking for, and likely as not it’ll sound better too. You don’t have to look much further than the previous question for good example of what’s available right now (and there’s plenty more to come…).

 

The Marantz SR5200 has received some excellent reviews in the past few months and will set you back just £400. For that you get a beefy 6 x 90 watts AV receiver with Dolby Digital EX, dts ES Dolby Pro-Logic II, an RDS tuner and it even comes with a learning remote. If your pockets are a little bit deeper, and since you are a Yamaha fan, how about the RX-V1200, which meets all of your surround sound decoding requirements, it pushes out a very healthy 80 watts per channel and sells for a little under £650. If you really want to splash out you should have a close look at the mighty Yamaha DSP-AZ1, which is currently selling for just under £2000.

 

 

QUICK TIP

Dolby Digital EX and dts ES are uprated versions of the original 5.1 channel digital surround systems that add an extra centre rear channel to the mix. In the case of Dolby Digital EX the extra channel is encoded into the stereo rear channel and extracted by the decoder so it is not a separate channel as such. The same applies to dts ES ‘Matrix’, however, there is also a variant called dts ES 6.1 ‘Discreet’, which does involve an additional channel, encoded into the digital bitstream. 

 

 

 

 

Name                Henry Muir

Kit                    Pioneer DV646A and Marantz SR5200 Receiver

Reply                I'm thinking of buying the above combo for both DVD home cinema and CD music playing.  Are they compatible, and what would be the best way of connecting them together?  Both seem to have Dolby Digital decoders - is this overkill?  If not compatible, can you suggest a better combo at a similar price? I’m also looking for a decent but unobtrusive speaker package to go with them that can deliver both home cinema surround and decent hi-fi from CD.  My JBL 100T's are just too prominent! I'm attracted to the Mission FS-2AV flat panel speaker package.

 

Reply

There are no reasons why the Pioneer 646 and Marantz SR5200 shouldn’t live together happily ever after. Compatibility issues between DVD players and amplifiers are comparatively rare since they use industry standard connection schemes (line level audio and digital bitstream), and both products are designed for the heavily populated centre ground of the home cinema market, where a high level of mix and match is to be expected. As you point out the 5.1 decoder in the Pioneer player is largely superfluous but on this model the key feature is DVD-Audio replay. Unless that is important to you then have a look further down the range, at the DV 545 or even the DV-444.

 

When it comes to the aesthetics of speaker design beauty is very much in the eye of the beholder and in the end only you can decide what looks good in your living room. In general terms with the Mission package you’re paying for the flat-panel design (see Getting Started), it’s also very convenient but the for same amount of money you should be able to achieve a more dramatic and involving sound from conventional, though admittedly less discreet, speakers.

 

 

 

Name                John Roche

Kit                    Samsung N505

Problem            Following your review of the Samsung N505, in particular it’s ability to handle DVD-R’s, I bought one and horror of horrors – when I popped in my newly created DVD-R, fresh from my iMac, only to experience jarring movement and intermittent - followed by complete - loss of sound. The Samsung plays commercial DVD’s perfectly and my iMac plays this DVD perfectly, did I buy the wrong DVD player?

Reply

Unfortunately DVD-R replay is not a part of the DVD specification and to date very few manufacturers make any claims for their player’s ability to handle the recordings. At the moment it’s not seen as a major selling point since so few DVD recorders are on the market, moreover it’s by no means clear which of the two competing formats will prevail, so most companies are playing safe and keeping their options open. The other problem is that we have noticed differences in DVD-R recordings made on different machines, and we have come across a couple of machine recently that will play DVD-Rs made on a Hitachi DVD camcorder, but not discs recorded on a Panasonic DVD recorder. From what you’re saying it now appears that there may also be differences in DVD-Rs recorded on an iMac – that’s all we need…

 

It’s all very confusing, and there’s no immediate prospect of it getting any easier, all we can say is that we test every DVD player that comes our way for DVD-R and DVD+RW compatibility on discs we’ve recorded but in the end, if it’s not a published feature there’s nothing to stop manufacturers enabling or disabling the facility by changing the firmware for example, without letting anyone know. It’s a bit late for you but for anyone else the best suggestion we can make is that if you’re buying a DVD player and compatibility with an existing DVD-R device is important, take a disc along with you and ask to try it out.

 

 

GETTING STARTED 1 – FLAT PANEL SPEAKERS

Flat panel speakers sound like a new idea but they have actually been around in one form or another for at least the past 50 years. However, they’ve only been seriously considered for hi-fi and AV applications since 1997, when the UK Company NXT began licensing its highly innovative flat panel technology.

 

Research began back in the early 1990s, following the discovery that the lightweight composite materials used in the construction of fighter aircraft exhibited unusual sound resonating properties.

 

A conventional loudspeaker uses a flexible cone, which is moved back and forth – like a piston -- by an electromagnet. This creates sympathetic vibrations in the air in front of the cone, which we hear, as sound.

 

In contrast NXT speakers are constructed from thin flat rigid panels with a small device called a transducer mounted on the back. This vibrates – producing movements of just a fraction of a millimetre -- creating a complex pattern of waves across the surface of the panel, which overlap and interact with each other. The semi-chaotic interactions at the many ‘nodes’ are what generate the sound waves.

 

In a normal loudspeaker sound waves are concentrated into a cone-shaped beam and this produces ‘sweet spots’ in the room, which has a big influence on speaker positioning, and where you sit. Flat panel speakers, on the other hand generate a much more evenly dispersed soundfield, which has some benefits for home cinema, though surround sound also depends on some sounds being tightly focused – like effects and the centre front dialogue channel – and on low frequency sounds, which NXT panels are not so good at producing, compared with a sub-woofer. It’s unlikely that NXT panels on their own will ever provide a complete solution for home cinema but used in conjunction with normal speakers and subs they are starting to make inroads, especially in installations where the panels can be effectively made to disappear (or stand out) by incorporating them into the décor.

 

 

GETTING STARTED 2 – DOLBY PRO LOGIC II

 

Pro Logic II is an interesting update on the original analogue surround sound system, developed almost 20 years ago by Dolby Labs. The key feature in DPL II is the ability to create a rich and authentic sounding multi channel soundfield from a stereo source. One of the most noticeable differences between the original system and DPL II is in the makeup of the channels and instead of the single narrow bandwidth rear channel of DPL I, (split between two speakers), DPL II has two full range stereo rear channels and under ideal conditions it is claimed DPL II gets close to the drama and impact of a digital 5.1 channel surround sound system.

 

In many ways Pro Logic II relies on a back to basics approach, dispensing with many of the enhancements that have crept into DPL decoders over the years. The raw sound actually passes through fewer stages of processing so less of the original is lost and instead of artificially creating ‘spatial’ effects, by introducing echo, reverberation and time delays, DPL II uses ‘servo circuits’ that seek to extract the natural ambience information that exists in the original recording.

 

Pro Logic II decoders have several operating modes. ‘Movie’ is for films or TV programs with Dolby Surround soundtracks, and also video games (several Playstation 2 and Game Cube titles now feature DPL II engineered soundtracks). ‘Music’ mode is optimised for stereo sources such as CD, MiniDisc and tape cassette. Most decoders also have controls that let you change the shape of the soundfield with adjustments for centre channel ‘width’; ‘panorama’ alters the perceived depth of the main right and left channels, and ‘dimension’ is used to shift the front/rear balance. Additionally many decoders also have a ‘matrix’ mode, which generates a surround soundfield from a mono audio source.     

---end---

 

Ó R. Maybury 2002, 1105

 

 

 

 

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