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BOOT CAMP 242 (10/09/02)
SPEAKERS AND SOUNDCARDS part 2
The loudspeakers supplied with most computers are usually
dreadful little plastic boxes with the all of the acoustic qualities of a rusty
baked bean tin. Normally it doesn’t matter too much as most of the noises
they’ll be called upon to make are the bleeps and pings made by Windows and
office applications but if you want to listen to music on your PC – play audio
CDs or MP3 files for example – you may be disappointed with the sound
quality.
Whilst it would be stretching things slightly to compare the
average desktop computer too closely with hi-fi equipment, most are nonetheless
capable of reproducing good quality sound, given the opportunity. You can easily
demonstrate your computer’s audio capabilities by plugging a decent set of
headphones in to the jack socket on the front of the CD-ROM drive and playing an
audio CD. Unfortunately this trick only works with music CDs but it’s a
start.
The simplest and usually the most effective way of improving
PC sound is to replace the speakers. As we discussed last week most PC
soundcards have a small built-in amplifier that can drive a loudspeaker
directly. It’s worth trying a pair of redundant bookshelf type speakers from an
old hi-fi system, which you can wire it up using a stereo jack lead to phono
lead (obtainable from most audio and video dealers). It’s probably not going to
be very loud but PC speakers are usually sited quite close to the user so it may
not matter too much.
If you are using a CRT type monitor keep the speakers well
away from the screen as the magnets inside may cause colour ‘staining’. PC
speakers and those used in home cinema systems are magnetically ‘shielded’ and
these can be used in close proximity to the monitor; LCD monitors are not
normally affected by magnetic fields.
If the output volume is unacceptably low you will either have
to resort to an external amplifier – a good use for an old stereo amplifier – or
use an ‘active’ or amplified speaker. In general those designed for hi-fi and
home cinema applications are better built and deliver more agreeable sound,
compared with most dedicated PC speakers, and it’s usually easier to figure out
what you are getting. PC speaker manufacturers often make extraordinary claims
for their products. The amplifiers in many speakers – some of them housed in
enclosures not much larger than a box of household matches -- apparently put
many powerful audio amplifiers to shame with power outputs in excess of 200
watts! Needless to say these are not the real-world ‘rms’ watts but airy-fairy
‘peak music power’ (PMPO) watts, so check the small print. Most PC speakers are
rated at between 1 to 5 watts rms, which might not sound much but don’t forget
you’ll be sitting quite close to them.
The soundcards and adaptors on many recent PCs have
multi-channel surround sound outputs that drive extra speakers placed all around
the seating position. You may or may not find having sound coming at you from
all directions entertaining, but be warned that it entails a lot of extra cables
and boxes all over the place. It’s worth trying if your PC is fitted with a
DVD-ROM drive and you use it for watching movies, or if you play a lot of games.
In both cases you will find that most movie soundtracks and action games carry a
lot of low frequency bass effects, which can add drama and atmosphere to the
proceedings.
However, PC speakers are not usually capable of reproducing
large amounts of bass so you will need a separate speaker dedicated to
low-frequency sounds, called a sub-woofer. These are usually a lot larger than a
normal speaker but because of the non-directional nature of bass sound they can
be placed almost anywhere within the room where the PC is used.
Upgrading your sound card can make a difference to sound
quality, particularly when playing games or when using music-based applications.
As a rule it’s worth doing if your current soundcard or adaptor is an FM
Synthesis type, the next step up the quality ladder is a Wavetable type (see
Boot Camp 241). It’s a fast-moving market so if you are serious it’s worth doing
some homework first, to check which models best suite your particular
applications.
Fitting a soundcard is not a difficult job, in many cases all
you have to do is swap the new card for the old one and load the driver software
from a CD-ROM. However, if your sound
adaptor is built into the motherboard it will have to be disabled before you can
install the new card and this may entail moving ‘jumpers’ on the motherboard or
changing settings in the PC’s in BIOS. Either way, unless you know what you are
doing you should consult your motherboard manual or a knowledgeable friend,
before you begin.
Next week – Protecting your PC
JARGON FILTER
COLOUR STAINING
A build up of magnetic fields on metal components inside a
CRT picture tube causes patches of colour on the screen. Normally this is
neutralised by a ‘degauss’ coil inside the monitor but in sever cases it may
require expert attention
MP3
Motion
Picture Experts Group audio layer 3 -- digital audio compression system commonly
used to send files containing audio and music over the
Internet
RMS
Root Mean Squared – in audio terms a measurement of the
continuous and sustainable output power rating of an amplifier as opposed to
transient or ‘peak’ power levels
TOP TIP
Just about every computer peripheral, pocket sized gadget and
power tool comes with a plug-in mains adaptor or charger and due to the nature
of portable devices they soon become separated, which frequently results in
lively hunt the charger sessions. The trouble is they all look the same, as do
the connecting plugs, but they’re not and there is a very good chance of frying
the widget concerned if the wrong adaptor is used. The solution is to label each
adaptor as soon as it is unboxed, or make maybe a way to use up all those
surplus coloured dots and stripes that come with year planners.
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