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                                     10




                                 Multi-Media























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Chapter 10 - Multi-Media

     
     Multi-Media computers (also called MPCs) are becoming more and more
common as their ability grows in popularity.  The term Multi-Media isn't an 
exact phrase, but it generally means the use of graphics and sound on a 
computer.  Since most good sound comes from audio CDS (compact disc), and heavy 
graphics take up so much space, Multi-Media usually means the computer has a 
CD-ROM drive.  If you want to take advantage of the thousands of available 
multi-media software titles that mix graphics, sound, and video, then you should 
buy a multi-media computer.  If you already own a non-multi-media computer, kits 
are sold that upgrade your existing computer to a multi-media computer.

     When you're buying a multi-media computer, don't be afraid of spending
more money to get superior multi-media ability.  I'm not talking about spending
more for the computer itself, but spending more to get better multi-media parts
(sound board, speakers, CD-ROM drive, etc.).  This will give you a better 
sounding system with smoother graphics.  Now, obviously, if sound is more 
important to you then you can spend more for the sound card itself and get an 
average CD-ROM drive or vice-versa.  Most computer dealers will allow you to 
tell them exactly what you want and don't.

     CD-ROM drives are like audio CD players because they will also play your
favorite audio CDS, but in addition they will read what's called a CD-ROM disc. 
CD-ROM is short for Compact Disc-Read Only Memory.  In English this means it's
a CD that can only be read from and not written to like a hard disk drive or 
floppy disk.  CD-ROMs cannot be used in audio CD players, because of the way the 
CD-ROM is made and the fact they contain data (like floppy disks) and not music.  
That doesn't mean that there may not be music on the CD-ROM, only that the music 
on the CD-ROM is specifically written so it can only be read by CD-ROM drives.

     For a computer to make sound, some kind of "Sound card" is required and
these cards can almost always be found in Multi-Media computers.  However, not
all sounds cards are created equal.  Two companies (Creative Labs, Inc. and 
Adlib, Inc.) have really set most of the standards in the industry.  Therefore, 
most companies make their programs compatible with these two company's sound
standards.  When you're looking for sound cards, look for compatibilities 
developed 















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Chapter 10 - Multi-Media


by these companies.  The following shows two sound cards (one low-end and one 
high-end), their features and prices.


     Low-End                       High-End
     -------                       --------
Sound Blaster compatible      Sound Blaster compatible
Adlib compatible              Sound Blaster Pro & SB 16 compatible
8-bit only sound              Adlib compatible
8-bit bus connector           8 & 16-bit sound
FM Synthesis MIDI support     16-bit bus connector
poor to fair sound quality    15+ voices
Average Price: $50-$100       Wavetable MIDI support                                           CD (IE. Great) quality sound
                              Average Price: $100-$700      


     CD-ROM drives come in several speeds and obviously, the faster the drive,
the faster it can retrieve data from the CD-ROM so you're not slowed down by 
the CD-ROM reading the disc.  This is especially true when dealing with heavy
graphics and animation (being read from a CD-ROM).  If the drive is too slow 
then the graphics or animation will appear choppy instead of "fluid" like 
images on your television do.

     The very first CD-ROM drives are called Single speed drives because they
read the data on a CD-ROM and the music on an audio CD as the same speed (ie.
one speed or Single speed).  A year or so later, Double speed CD-ROM drives hit
the market.  They are the same as single speed CD-ROM drives with respect to
reading the music on an audio CD, but they read the data from a CD-ROM at
"Double" the speed of a single speed drive.  Triple speed drives read a CD-ROM 
at "Triple" the speed of a single speed drive and I will bet that you can guess 
that a Quad speed drive reads the CD-ROM at Quadruple the speed of a single 
speed drive.  The newest and fastest CD-ROM drive is called a 6X speed drive,
and it reads a CD-ROM at 6 times the speed of a single speed drive.

     Figure 10a shows the difference between various speed CD-ROM drives.
Normally, CD-ROM drives have their speed measured in how many kilobytes per














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Chapter 10 - Multi-Media


second (KB/sec) of data they can read from a CD-ROM.  Displaying graphic
animation using a single speed drive (at 150KB/second) would look very choppy
while animation on a 6X speed drive would look very smooth.  Also, loading
programs from a single speed drive will be slower than from a 6x speed drive.

     MIDI (short for Musical Instrument Digital Interface) is a standard 
designed to allow a computer (through a MIDI compatible sound card) to control 
digital musical instruments.  For example: electric drums, synthesizers, 
keyboards, and digital mixers call be controlled with a computer and this allows 
a great deal of power in mixing and editing music.  A number of bands use this 
technology to help them when they perform in concert and are recording new 
songs.


                      CD-ROM Drive Speeds

                ----------------------------------
                |
       6X Speed |*************************** 900
                |
Quadruple Speed |****************** 600
                |
   Triple Speed |************** 450
                |
   Double Speed |********* 300
                |
   Single Speed |**** 150
                |
                ------|-----|-----|-----|-----|---
                 0   200   400   600   800   1000

                      Kilobytes per second

Figure 10a - The current speeds a CD-ROM drive can read data (larger
             numbers are better).















Help Guide to Buying a Computer


     


Chapter 10 - Multi-Media
     
     
     Multi-media computers have a lot of other uses (besides those mentioned
above) both in the business world and at home.  They allow playing, editing, and
recording of any type of sound or video to or from the computer.   For example:
Since I'm a Star Trek fan, I have all sorts of Star Trek sounds and voices on my
computer just to make the computer more interesting and less routine.

     One feature that largely separates the superior sound cards from the 
inferior sound cards is the type of MIDI (FM synthesis or Wavetable synthesis) 
it supports.  Wavetable synthesis is the superior type of MIDI.  Therefore, if 
you are a composer or just serious about better sound, then get a sound card 
that has wavetable synthesis MIDI support.  Wavetable synthesis is essentially a 
stored bank of sampled notes recorded from actual acoustic  instruments.  
Wavetable sounds are much more realistic than those created by FM synthesis.  
Unfortunately, sound boards that support wavetable synthesis are more expensive, 
but they're worth it.  FM synthesis mimics the notes and timbre of instruments 
using operators or sine waves, and its reproductive powers are limited.  Even 
the most inexperienced listener will immediately identify its tinny sounding 
notes as those of a synthesizer.

     Most multi-media computers come with small, inferior speakers that really
don't allow the computer to sound its best.  If you're want the most out of your
multi-media computer then buy better speakers (and don't use the speakers that
come with the computer or the multi-media kit).  Generally, better speakers are 
the same type of speakers (except for how they attach to the computer) that you 
would buy for a home stereo. These speakers cost more, but they are worth it 
because your computer's sound can now really be heard.  
























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