FEATURE

HEAD

HOME CINEMA FOR BEGINNERS...

COPY

Home cinema is all about recreating the sensations of watching a movie at the cinema, in your own living room. There’s two ways of going about it; the first involves chucking a load of half-eaten ice-creams on the carpet, eating week-old hot-dogs and asking the neighbours in to have an argument whilst you try to watch a movie on video. It’s cheap and quite realistic, but not particularly satisfying. The alternative is to invest in a few extra pieces of equipment, to go with your TV, VCR and hi-fi, that will turn your sofa into the best seat in the house.

It needn’t be expensive, providing you’ve already got a fairly recent TV and video recorder, a basic set-up could cost you less than couple of hundred pounds, but be warned, the sky’s the limit. If you get bitten by the bug you could easily spend £2000 without blinking, and that’s before you add on the cost of an extension to your house, and the usherette’s wages...

So where do you start? The technology can appear bewildering at first, but don’t let that put you off, the phrases you’re going to see over and again are Dolby Surround and Pro Logic, all you need to know at this stage is that they refer to sophisticated multi-channel surround sound systems that were originally developed for use in movie theatres, but are now available in an affordable domestic form; we’ll go into the why’s and wherefores later on. You might also be wondering how it is possible for a  standard British living room to sound anything like a cinema auditorium, believe it or not it can be done, and it doesn’t involve knocking down walls, surgical implants or mind-altering chemical substances! But do you really need all this extra technology in your life? Well, that’s up to you, but it might help you to know that every time you watch a movie on TV or video you could be missing out on some pretty dynamic effects; and if you’ve ever wondered what it’s like to have big Arnie blowing up petrol tankers on the rug in front of you, or the Batmobile screaming out from behind your settee, then this is your chance to find out!

KITTED OUT

So what exactly do you need?  There’s several different routes into home cinema, from upgrading or integrating your present video and audio equipment, to starting from scratch. There’s no right or wrong method, it all depends on what you’ve got now, how far you want to go, and how much you’re prepared to spend. Upgrading suits most people to begin with, though there are pitfalls to be aware of. Obviously you need to have a stereo hi-fi video recorder, and some sort of hi-fi system in the first place. There’s going to have to be changes; the hi-fi will have to be positioned close to the TV and VCR, and the speakers must be placed a foot or two either side of the TV screen, and that may not always be convenient, especially if the system is still going to earn it’s keep as a hi-fi, or if other members of the family want to use it, when you’re watching movies.

We spoke a moment ago about the need for a stereo VCR, that’s not strictly true, there’s other source components you could use, like a stereo satellite tuner, or maybe a laser disc player, but a stereo VCR, preferably one made within the past five years with a NICAM decoder, is going to give you access to the widest range of material.

So, assuming you already have the core components -- a decent size TV, stereo VCR and hi-fi system, what else do you need?

DOLBY PROCESSORS

The minimum requirement for a home cinema system is a Dolby Surround decoder or processor, and some extra speakers. In the early days -- three or four years ago -- there were two types, known as ‘active’ or ‘passive’. Passive decoders, which can only resolve one extra channel (see The Dolby Story), have all but disappeared, nowadays most decoders rely on active or ‘Pro Logic’ technology to extract four sound channel. The decoder box connects between the output of the AV source component --  VCR, satellite tuner etc. -- and the auxiliary input of the hi-fi amplifier. Amplifiers built into the decoder drive a pair of small speakers placed behind the viewing position, and (in the case of a Pro Logic decoder) one in front of the TV screen. The main stereo channels are heard through the hi-fi’s own speakers. Stand-alone Dolby processors are the cheapest, and oddly enough, also the most expensive home cinema components, with prices ranging from under £200 to almost £1800.

AV AMPLIFIERS

Purpose designed AV amplifiers, with built-in Dolby Pro-Logic decoders, are normally the most flexible option, and relatively speaking not much more expensive than stand-alone decoders with prices starting under £350. They have several advantages, including keeping the box count low by providing up to five channels of amplification, enough to drive all of the speakers in the system. AV amps also take control of the function and mode switching for the other components in the system, and several models have built-in AM/FM tuners as well, which helps simplify matters even further.

A growing number of AV amps also contain additional digital signal processor (DSP) systems, to liven up non-Dolby encoded audio and video material. DSPs simulate the acoustic properties of a wide range of musical and theatrical venues, from open air stadia, to small intimate jazz clubs, some are even based on actual measurements taken from renowned theatres and opera-houses. DSP works by adding small amounts of reverberation (echo) and delay to sounds coming from the speakers -- recreating reflected sounds that give an impression of space -- and selectively filtering certain frequencies, to mimic the reflective and absorptive characteristics of various types of building materials and furnishings.

AV SYSTEMS

The next step up the ladder is a fully integrated AV system, with the Dolby Surround decoder built in. They make a lot of sense for those who do not have a hi-fi system to upgrade, do not want to use their existing hi-fi for AV purposes, or shift speakers around every time they watch a movie. Systems vary considerably in scope and performance, starting with the simplest two-box minis costing around £750, rising to £1500 plus for systems that include semi-exotic AV components,  like laser disc players, CD auto-changers or fancy speakers. One of the biggest advantages with this kind of set-up is an integrated control system, usually with the whole system operable form just one remote handset. This is home cinema for the techno-cautious, they retain most of the flexibility of component systems, but without the  bother of mixing and matching equipment from different manufacturers.

SURROUND SPEAKERS

A lot of companies have cottoned on to the fact that home cinema systems need extra speakers. The fact is, the extra channels, which carry surround sound effects and dialogue, operate over quite narrow frequency bands, at relatively low power levels, and you really don’t need anything too fancy for that. Most reasonably competent book-shelf speakers -- costing between £50 to £70 -- are perfectly adequate in this application. The only thing to watch out for is the centre-front dialogue speaker, which needs to be placed fairly close to the TV. It’s possible that the speaker magnet might cause colour staining on the screen. In which case move it a little further away; the staining should disappear quite quickly, all TVs have built-in ‘degauss’ coils which automatically demagnetise the screen every time it’s switched on. If you’re really worried you can always get a magnetically shielded centre-front speaker, they start at around £50 but try an ordinary one first.

There is still some debate over the effectiveness, or otherwise, of specially designed AV speakers, and speaker packages, that variously claim to create wider, narrower, longer or shorter soundfields. The best advice we can give it to have a listen for yourself, but only after you’ve heard what your own speakers can do first. If you think AV speakers sound better have a go, but be prepared to bash the plastic, some of these outfits can set you back £1000 or more, though cheaper ones are available, from around £300 or so.

DOLBY TVs

Dolby Surround decoders have popped up in all sorts of places over the past few years, from VCRs to satellite tuners, but after AV amps and Dolby systems the next most logical location is inside a TV. This is the classic ‘one-box’ solution for those who do not want the aggravation of connecting their hi-fi up to the VCR and TV, or maybe don’t even have a hi-fi. There’s half a dozens models on the market right now, costing from £800 upwards, and they all come with the necessary external speakers and cables. They’re all very easy to set up and use but, it has to be said, are the least effective sound-wise, due to the limitations of built-in speakers. However, some models can be fitted with external speakers for the main stereo channels, then they don’t sound half bad.

A WORD ABOUT TELEVISIONS

Whatever else you get you must have a proper TV. Size does matter, it’s no good trying to build a home cinema system around a 14-inch portable. Spectacular effects that sound as if they’re coming from two streets away just don’t work when your eyes are focused on a squitty little picture, that occupies just a fraction of your field of vision. Don’t mess about, think big; what you need is a TV with at least a 25-inch screen. 28-inches is better, but as  general rule get the biggest set your bank account and floorboards can stand, and if you’re serious nothing less than 33-inches will do. Above that you’re into projection TV territory, and it’s not just money you need, but a big dark room as well.

By all means get a NICAM stereo TV -- you have little choice anyway on sets over 25-inches these days --  but it has to be said that most of them have horrible little speakers that are set far too close to the screen to produce any kind of stereo image, you’ll normally get a much better sound from separate speakers.

How about widescreen TV?  The problem is there’s no widescreen material to watch at the moment. A few movies shown on TV or on video are in a letterboxed format, and widescreen TVs have the facility to blow them up to full screen height and width, but this results in a drastic loss of definition, a 405-line picture in fact, a real blast from the past... There’s a lot going on behind the scenes right now, with digital transmission systems, high definition, PAL-Plus and various other technical advances, so it might be a good idea to wait for a year or so before you pour big bucks into a widescreen TV. If you buy a widescreen set now be aware that it may not be possible to update or upgrade it, if and when new technologies are introduced.

BOX COPY -- THE DOLBY STORY

There’s still a lot of confusion surrounding Dolby Surround, starting with the terms Dolby Stereo, Dolby Surround and Dolby Pro Logic. There’s no mystery. Movies shown in the cinema have Dolby Stereo soundtracks, when they’re re-formatted for TV, or video, it becomes known as Dolby Surround; made for TV programmes also have Dolby Surround soundtracks. Pro Logic is the name of a high-performance decoder system, so far so good?

So what exactly is Dolby Surround? Basically it’s a way of encoding four sound channels into a normal two-channel stereo soundtrack. The beauty of it is Dolby information is very robust and can survive intact on any reasonably good quality stereo recording or transmission system (VHS hi-fi, NICAM, satellite stereo etc.). Moreover, it sounds perfectly normal on conventional stereo equipment, but when it passes through a Dolby decoder the extra two tracks can be heard as well.

The four channels consist of the right and left hi-fi stereo channels, plus two lo-fi channels which carry sound effects, heard through speakers behind or to the side of the viewer, and speech or dialogue. The latter was originally intended to help focus a cinema audience’s attention on the screen, no matter where they are sitting in the auditorium.

---end---

Ó R Maybury 1994 1907