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FEATURE
HINTS AND TIPS SPECIAL -- PART 1
GETTING STARTED
Dolby Pro Logic, SR-D, THX,
digital surround ... It’s easy to get embroiled with home cinema technology,
but back in the real world stereo TV sound will be most people’s first
encounter with the audio-visual revolution. Television sound in the UK remained
stubbornly monophonic up until five years ago. Before that the only stereo AV
sound sources were pre-recorded video tapes and laser discs. Then in 1989 the
BBC and ITV began broadcasting in stereo, they’ve since been joined by a clutch
of stereo satellite channels. Stereo TVs and VCRs have become much more
affordable, but there’s still a lot of confusion surrounding the subject, and
far too much misleading hype.
Don’t be put off, the whole
business is lot simpler that it appears, if it’s broken down into bite-sized
chunks. For example, there are only four stereo AV sources to worry about:
terrestrial TV, satellite TV, video tape and laser disc, (five if you count
video games, but that’s another story...), and only two ways of listening to them:
through a stereo TV or through a hi-fi, connected to a stereo VCR.
But where do you begin,
once you’ve decided to go stereo? The logical starting point is terrestrial TV,
after that everything else clicks into place. Both the BBC and ITV use a system
called NICAM, where the stereo sound signal is transmitted on a slightly different
frequency to the vision and mono sound signals, this reduces the chance of
interference, and ensures compatibility with existing, mono equipment. NICAM decoders
are built into stereo TVs and stereo VCRs, there used to be a few stand-alone NICAM
tuner on the market but they’ve mostly disappeared now.
NICAM TV’s are the way to
go if you want to keep things simple, there’s nothing more to buy, just plug it
in and providing you’re not one of the unfortunate 5% who cannot receive stereo
broadcasts -- check first! -- you’re in business. If you’ve got a stereo
satellite receiver you can connect that to the TV’s audio input, so you can hear
satellite channels in stereo as well.
There’s a couple of points
to bear in mind with stereo TVs, though; the most obvious one is you cannot
record TV programmes in stereo, unless of course you have a stereo VCR -- we’ll
come to that in a moment . Secondly, some stereo TVs are not all they’re
cracked up to be. Most of them have squitty little speakers stuck behind narrow
slits down the sides of the screen. Not to put too fine a point on it, many stereo
sets -- especially the cheaper ones -- sound pretty mediocre, it’s difficult to
tell whether you’re listening to a stereo programme or not on some of them! A
handful of sets, in particular those with side-mounted speakers, or in
detachable pods, sound a little better, and a few -- very few -- have carefully
designed speakers and extra low-frequency ‘sub-woofers’ drivers. They sound
great, but in the main it’s fair to say that the sound quality on stereo TVs comes
a poor second place to the cosmetics.
That brings us to stereo
VCRs. Since the late 1980’s pretty well all VCRs with stereo hi-fi sound
systems have had built-in NICAM decoders, which is the best place for them when
you think about it. It means that you won’t have to buy a new TV if your
present one still has some life left in it; in any case stereo VCRs are usually
a lot cheaper than stereo TVs. You’ll be able to record TV programmes in stereo,
and that includes the satellite channels; and don’t forget most pre-recorded
movies on tape have stereo soundtracks. However, the best part is that you will hear the stereo sound to its best
advantage, by piping it through your stereo hi-fi system -- assuming you’ve got
one of course... It doesn’t even have to be a top-notch system, even budget
hi-fis will often do quite a good job However,
all that is easier said than done. In most homes the video and the hi-fi are
rarely next to one another, or even in the same room, so this approach to
stereo TV sound often entails a fair amount of upheaval, but it’s well worth
the effort.
So how does it all work? A
minimum system will normally comprise a TV, probably mono, preferably one with
a largish screen (25-inches or above), a NICAM stereo VCR, the hi-fi system and
speakers, and possibly a stereo satellite tuner. The first step is to get them
all together in one place, including the speakers which should be placed either
side of the TV screen. Most of the existing connections remain as they were;
the feed from the TV aerial goes into the back of the video recorder, and the
aerial lead from the VCR goes to the back of the TV. If there’s a satellite
tuner in the system this can be ‘daisy-chained’ between the aerial downlead and
the VCR.
Most VCRs have only one
SCART socket, this should be used to connect it to the TV, for the best
off-tape and off-air picture quality. This may mean you won’t be able to record
satellite TV programmes in stereo, though if the VCR has a separate audio
line-input -- and quite a few do -- you can connect it to the stereo output
sockets on the satellite tuner, with a stereo phono-to-phono lead. The VCR’s
stereo line-out sockets are connected to the auxiliary (aux.) input on the
stereo amplifier. If the VCR doesn’t have a line input the stereo output from
the satellite tuner should also be connected to the stereo amp, using a spare ‘tape’
or ‘CD’ input via a stereo phono-to-phono cable. Incidentally, you can use the
same basic technique to improve the sound quality of a stereo TV; most of them
have line-audio outputs which can be hooked up to the hi-fi system’s aux. input,
just mute the TV sound and listen to it through the hi-fi speakers.
AV leads are not terribly
expensive, a decent SCART-to-SCART cable costs about £8. There’s a few points
to watch out for; make sure you get a ‘Type C’ (aka 9-pin) or ‘Type U’ (aka
21-pin) lead, which are configured for video and audio signals; (a Type U lead
is necessary if you’re using a Super VHS video recorder with a TV that has an S-Video
configured SCART). SCART leads are very widely available from most video and
audio dealers, electrical shops and high-street chains. Most of them are 1.5
metres long, which is fine for most installations but if you need a longer one
you will have to go to a specialist dealer. A growing number of SCART
connectors have gold-plated contacts, they’re worth having because they won’t
corrode and should maintain good electrical contact longer. Take all the nonsense
about improving picture and or sound quality with a large pinch of salt, and
don’t be fooled into paying a lot more for them. There are several good ones
around for £10 or less. Stereo phono-to-phono leads are, or should be quite
cheap, in fact one or two freebie leads are usually supplied with AV products.
They cost a pound or two to buy, and again beware of overpriced gold-plated
leads.
To sum up, unless you’re
prepared to shell out on a top-end NICAM TV, (and you’ll still need a NICAM
stereo VCR if you want to record TV programmes in stereo), the best course is
to get a stereo VCR and connect it up to your hi-fi system. This is the most
flexible approach, it’s cheaper -- NICAM VCRs start at under £300 -- it’s the
first rung on the home cinema ladder and will give you the best sound.
BOXOUT 1
LIVING WITH STEREO SOUND
There’s more to stereo television sound than just having the
sound coming from two speakers, instead of one. To get the full spatial effect
it’s important to have a well-focused stereo image, and that may mean
re-positioning the TV in the room, so that the speakers can be placed a foot or
two either side of the screen. Don’t be afraid to experiment with various
speaker locations, but don’t move them too far apart as the sound can become
detached from the screen, which can be quite disconcerting. Some stereo
amplifiers have switchable outputs for a second set of speakers, use them if
you don’t want to devote the main stereo speakers to AV operations.
It may be necessary to move the furniture around, so that
the ideal seating position is a comfortable distance from the screen and in the
centre of the stereo sound-stage. Make sure other items of furniture don’t
create unwanted reflections or absorb sound from one of the speakers.
Connecting the TV, VCR and hi-fi together means they will
all have to be physically close together, it might be worth investing in a
purpose-designed AV racking system, or ‘home entertainment’ console -- available from your local furniture
superstore -- to house all of the
components, simplify wiring and reduce clutter. It will also make life easier
when it comes to controlling the system. Multi-function remote controls can be
a godsend, reducing the number of handsets to manageable proportions; several
models on the market can control up to half a dozen different devices.
BOXOUT 2
WALK-THROUGH CAPTIONS
* The lead from the TV aerial goes to the aerial input or
‘RF in’ socket on the back of the VCR. Connect the aerial output from the VCR
to the TVs aerial socket, using the lead supplied.
* For best picture quality the VCR should be connected to
the TV via their respective SCART sockets, though this will not give you stereo
sound, unless you have a pre-NICAM
stereo TV. Retain the aerial lead connection between the TV and VCR, this will
enable you to use the TV as normal, it may also be necessary to use the TV’s
own channels in order to receive teletext information as the data can be
corrupted or stripped out when the signal passes through a VCR.
* The stereo line-audio output sockets on the back of the
VCR are connected to the auxiliary input on the back of the hi-fi amplifier,
using a stereo phono-to-phono lead. If the amplifier doesn’t have a spare
‘aux.’ input you could use either of the ones marked ‘tape’ or ‘CD’, but do not
use the ‘phono’ input as this is configured for a completely different type of
signal, and you could end up damaging the amplifier’s input circuitry.
* Most stereo satellite receivers have line-audio outputs as
well, and these should be connected to the VCR’s line input, if it has one, or
the amplifier in the same way as the VCR, though you may have to sacrifice one
or more audio components. Alternatively, you could use a stereo audio switch
box, they’re widely available for between £16 to £20 from most video and audio
dealers. If the VCR has twin SCARTs, one of those could be used to connect it
to the satellite box, this will also enable stereo recordings to be made from
the satellite channels.
BOXOUT 3
A BRIEF HISTORY OF NICAM
NICAM evolved out of a digital audio transmission system --
called sound-in-synch or SIS -- developed by the BBC during the early 1970s, to
distribute TV sound around the network. By the mid 1980’s BBC engineers had
begun work on a digital stereo broadcasting system, based on sound-in-synch
technology; tests carried out in 1986 proved the system worked and didn’t
interfere with existing TV sets. In 1987 the specs were frozen, NICAM was born,
and decoder chips were developed by Ferguson and Texas Instruments; test
broadcasts began in earnest from the Crystal Palace transmitter in South London
and Wenvoe in Wales, the latter was chosen for the surrounding rough terrain,
which tested the signals durability.
Due to a lack of stereo material the public launch was a low
key affair. Funding problems at the BBC prevented them from being first, it was left to ITV companies in London and
Yorkshire, and Channel 4 to officially begin NICAM transmissions in September
1989, initially with just an hour or two of programming each day. Today around
half of all TV programmes have stereo soundtracks, and the service reaches
around 95% of the population, the remaining 5% -- mostly in isolated rural
areas served by small relay transmitters -- may have to wait until the turn of
the century to get NICAM.
BOXOUT 4
GLOSSARY
AV
Audio-visual or Audio and Video; term used to describe items
of home entertainment equipment or systems that operate with, integrate or
process both picture and sound signals.
CO-AXIAL
Type of screened cable and connector used to carry very high
or ultra high frequency (VHF/UHF) signals from an aerial to a TV, VCR or FM
radio. Aka ‘Belling’ and RF connectors.
COMPOSITE VIDEO
Video signal containing brightness (luminance), colour
(chrominance) and picture synchronisation information; see also S-Video.
HI-FI STEREO
Recording system used on stereo VHS video recorders. Aka DFM
or depth frequency multiplexing.
NICAM
Near-Instantaneously Companded Audio Multiplexing; high
quality digital sound transmission system developed by the BBC and used by the
BBC and ITV companies to broadcast stereo TV sound in the UK. Also used in Scandinavia
and New Zealand.
PAL
Phase Alternate Line; 625-line colour TV system used in the
UK, throughout much of Europe, parts of Africa and the middle East, Australia
and New Zealand.
PHONO
Simple screened push-fit connector system for carrying audio
and video signals. Aka RCA and Cinch
SCART
Syndicat des Constructeurs d'Appareils Radio Recepteurs et Televiseurs. 21-pin connector
system used to convey video, audio control and data signals between AV
components, widely used throughout EU. Aka Euroconnector and Peritel.
SR-D
Dolby Surround -- the next generation, providing up to six digitally
encoded surround sound channels
S-VHS
Super VHS; sub-format of VHS, using the same style of
cassette but capable of much improved picture quality.
S-VIDEO
Video signal broken down into its component parts -- to
prevent interaction -- with the brightness and chrominance components carried
separately. Used to convey signals between S-VHS (and Hi8) equipment
THX
Tomlinson Holman eXperiment -- surround sound system specification
devised by Lucasfilm, and licensed to home cinema equipment manufacturers.
WEGNER PANDA 1
Stereo sound transmission and noise reduction system used on
the majority of satellite TV channels
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1994 1910
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