The document summarizes different types of microphones and pre-recorded media sources. It describes dynamic microphones as versatile, sturdy microphones that do not require power. It explains that capacitor microphones can detect very high audio frequencies and are more sensitive than dynamic microphones. It also outlines that electric condenser microphones include a pre-amplifier that requires power, while crystal microphones use a piezoelectric material to convert sound into electrical signals. Additionally, it defines boom microphones, radio microphones, and several pre-recorded media sources like DVDs, CDs, hard disks, and MiniDiscs.

1. Microphone types and characteristics:
Dynamic Microphone:
(Research from Media College)
Dynamic microphones are
versatile and ideal for
general-purpose use. They
use a simple design with
few moving parts. They
are relatively sturdy and
resilient to rough
handling. They are also
better suited to handling
high volume levels, such
as from certain musical
instruments or amplifiers.
They have no internal
amplifier and do not
require batteries or
external power.
Capacitor Microphone:
(Research from Sound on Sound)
Capacitor microphones
are able to respond to
very high audio
frequencies, and they are
usually much more
sensitive than their
dynamic counterparts. In
other words, they require
less amplification than
dynamic models to
produce the same output
level from the same signal
source, making them
more suitable for quieter or distant sound sources. The reason capacitor microphones have such a
good frequency response is that their diaphragms can be made much thinner and lighter than those
of dynamic models, as they don't have to drag the mass of a voice coil along with them.

2. Electric Condenser Microphone:
(Research from Media College)
The electret condenser microphone uses a
special type of capacitor which has a
permanent voltage built in during
manufacture. This is somewhat like a
permanent magnet, in that it doesn't
require any external power for operation.
However good electret condenser
microphones usually include a pre-
amplifier which does still require power.
Carbon Microphone:
The carbon microphone, also known as carbon button
microphone, button microphone, or carbon transmitter, is a
transducer that converts sound to an electrical signal. It
consists of two metal plates separated by granules of carbon.
One plate is very thin and faces outward, acting as a
diaphragm.
Crystal Hand-Held Microphone:
(Research from hyper physics)
Crystals which demonstrate the piezoelectric effect produce
voltages when they are deformed. The crystal microphone
uses a thin strip of piezoelectric material attached to a
diaphragm. The two sides of the crystal acquire opposite
charges when the crystal is deflected by the diaphragm. The
charges are proportional to the amount of deformation and
disappear when the stress on the crystal disappears.

3. Rifle Microphone:
(Research from B&H)
A shotgun or Rifle Microphone is a long, cylindrical microphone that excels at picking up sounds in
front of it, while rejecting sounds to the sides and rear. Shotguns are designed to have a narrower
focus than an average microphone. Shotgunmicrophones do a great job of picking up the
frequencies the human voice produces. Their sound grabbing and voice-capturing abilities make
them a great choice for picking up on-camera dialog.
Boom Microphone:
(Research from the dictionary)
A pole carrying an overhead microphone projected over a film or tv set
Radio Microphones:
(Research from the dictionary)
A microphone incorporating a radio transmitter so that
the user can move around freely.

4. Pre-recorded sources:
DVD:
(Research from webpedia)
Short for digital versatile disc or digital video disc, a type of optical disk technology similar to the CD-
ROM. A DVD holds a minimum of 4.7GB of data, enough for a full-length movie. DVDs are commonly
used as a medium for digital representation of movies and other multimedia presentations that
combine sound with graphics.
CD:
(Research from tech terms)
Stands for "Compact Disc." CDs are circular discs that are 4.75 in (12 cm) in diameter. The CD
standard was proposed by Sony and Philips in 1980 and the technology was introduced to the U.S.
market in 1983. CDs can hold up to 700 MB of data or 80 minutes of audio. The data on a CD is
stored as small notches on the disc and is read by a laser from an optical drive. The drives translate
the notches (which represent 1's and 0's) into usable data.
Hard Disc:
(Research from webopedia)
A magnetic disk on which you can store computer data. The term hard is used to distinguish it from a
soft, or floppy, disk. Hard disks hold more data and are faster than floppy disks. A hard disk, for
example, can store anywhere from 10 to more than 100 gigabytes, whereas most floppies have a
maximum storage capacity of 1.4 megabytes.
MiniDisc™
(Research from PC mag)
A compact digital audio disc from Sony that comes in read-only and rewritable versions. Introduced
in late 1993, the MiniDisc has been most popular in Japan. The read-only 2.5" disc stores 140MB
compared to 650MB on a CD, but holds the same 74 minutes worth of music due to Sony's Adaptive
Transform Acoustic Coding (ATRAC) compression scheme, which eliminates inaudible signals. MD
discs store disc and track titles displayed by the player. Used for music recording, rewritable
MiniDiscs employ magneto-optic technology and come in 60 and 74-minute cartridges. The MiniDisc
drive for computers (MD DATA) never caught on.