Introduction to Home Theatre

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Introduction to Home Theatre

• By Christopher Caruso

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Topics To Be Covered

• What is Home Theatre Why is it becoming so
  poplar?
• Components that make up a Home Theatre system.
• Surround sound.
  -Basic set up
  -Popular
  formats
• Visual components.
• DVD VHS players

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What Is a Home Theatre System?

• A series of electronic components, designed with
  the purpose to recreate the cinema experience in
  the comfort of your lounge.
• The difference between the Home Theatre system
  and a conventional television set up is that the
  home theatre experience has the ability to
  engross the viewer in the movie
• Sound is directed from every which direction and
  with some set up bass is produced that can be
  felt throughout your body.
• Increasing popularity can be attributed to new
  technologies making these systems more compact
  and affordable

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Basic Components

• DVD/VHS player or other digital cable systems
  provide the weak video and audio signals.
• Amplifiers then boost the signal in order to
  become useable.
• Amplified sound signal is then processed in the
  receiver to be distributed to usually 5
  speakers.
• Video signal amplified in television to generate
  the visual display.

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Surround Sound Formats

• Dolby Surround Sound
• Dolby Pro Logic
• Dolby Digital
• Dolby Digital EX
• Digital Theatre Sound (DTS)

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Dolby Surround Sound

• Known as the poor mans surround sound
• Most basic form of surround sound available
• Two rear speakers, both playing the same rear
  channel, are connected to the existing front
  speakers

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Dolby Pro Logic

• Consists of 5 speakers, using 4 separate
  channels.
• Separate front (left/right) signals, center and a
  common signal (mono) supplied to the rear
  speakers.
• A basic setup, which provides a rich sound up
  front and a general noise sensation from the rear.

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Dolby Digital

• Otherwise known as Dolby Digital 5.1
• More separate channels provides a richer sound
• Named 5.1 indicating 5 separate ordinary channels
  and one effects (subwoofer), with a low
  frequency input signal, provides depth and a
  rumbling effect during on screen explosions.
• Signal is transmitted digitally which decreases
  unwanted speaker noise, commonly heard as a
  background hiss.

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Dolby Digital EX

• Format is similar to that of Dolby Digital 5.1,
  except a sixth speaker is positioned behind the
  listener
• Similar to the center speaker, this anchors the
  sound between the left right channels
• The signal used is extracted from the left and
  right rear speakers
• This isnt a very common format, but predictions
  are that it will be in the near future.

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Digital Theatre Sound (DTS)

• Commonly found in most modern cinemas
• Popular action DVDs like The Fast and The
  Furious are encoded in DTS
• Similar to Dolby Digital EX, making use of an
  additional rear channel
• Has higher data rates for encoding (1.5 Mbit/sec
  or 754 kbit/sec) 5.1 audio tracks, which is 2-4
  times the data rate of Dolby Digital
• This makes DTS up to 4 times less compressed
  allowing for much better sound quality and thus a
  better overall theatre experience

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Visual Components

• Vast improvement in the quality and experience of
  visual components
• Types
  -Standard
  direct view television
  -Rear-projection television
  -Plasma screens

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StandardDirect View Television

• Cheap to purchase, some under 300
• Utilize a cathode ray tube (CRT), with a scanning
  electron gun, which produces the picture, from
  the given signal, on a phosphor-coated screen
• Some good direct view televisions produce an
  exceptional picture, especially high definition
  with more lines of resolution
• allows the viewer to sit closer and still
• see a clear picture
• Limits of these televisions are that
• they are restricted in size due to
• tube technology
• Maximum viewing size is about
• 40 inches, or 101.6 cm diagonally
• across the screen

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Rear Projection Television

• These have very large screens, using 3 cathode
  ray tubes to split the video signal into 3 colors
  (blue, green and red). In different combinations
  these are all that is needed to produce the
  entire, visual, spectrum
• These cathode ray tubes are directed into a
  mirror that reflects the image onto the screen
• Advantages of these televisions are that you can
  obtain a large picture for a relatively low price
  45inch or 114.3cm for around 1500
• Disadvantages old models used to have low
  resolution and darker picture compared to the
  standard televisions and had to be viewed
  directly front on (perpendicular)
• New models have overcome these
• drawbacks and now rear projection
• televisions are of much higher
• quality than previous

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Plasma Screens

• Latest in television technology, a high
  definition picture with the screen itself being
  typically less than 6inches or 15.24cm in depth,
  making them very light and easily mountable on
  the wall or in small rooms.
• The picture is created using a collection of
  cells in a matrix formation in between 2 layers
  of thin glass with a coating of electrodes used
  to place a charge in a particular cell, which
  ignites the gas and thus changing it to plasma.
  The plasma gives off UV-light which stimulates
  colored phosphors on another layer, thus
  producing the colored light. Each cell is
  dedicated to one of 3 colors green/blue/red thus
  full visible spectrum can be created.
• Plasma screens offer a great picture
• but their downfall is their price,
• starting at around 6000 they are
• extremely expensive for their size.

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Audio/Video Signals

• DVD and VHS players are where the video/audio
  signals originate from
• DVD (digital versatile discs) players are
  becoming increasingly popular because they
• offer a very clear picture and crisp
• sound with many added features at
• a base level price of less than 200
• VHS are very trusted and popular, their
  horizontal resolution is much less than that of
  DVD though at 240lines vs 500lines
• Analogue sound is poor though as it can produce
  an annoying hiss through the speakers

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Conclusion

• Home theatre entertainment is producing some
  amazing new technological advances, but the one
  thing to remember when setting up your own home
  theatre is that your system is only as good as
  your poorest component.

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References

• http//www.google.com
• http//www.howstuffworks.com
• http//www.howthingswork.virginia.edu
• http//www.dvdcc.com