Learn how microphones should be placed and which microphones should be use for different purposes. Key words :- - What is microphone - Selection of Microphones - Types of microphones - PICK UP PATTERNS MICROPHONE - Placement of Microphone - Summary

1. Selection and placement of
microphones

2. What is microphone ?
Microphones converts sound into an electrical signal. Microphones
are used in many applications such as telephones, tape recorders,
hearing aids, motion picture production, live and recorded audio
engineering, megaphones, in radio and television broadcasting and
in computers for recording voice, speech recognition.
Most microphones today use dynamic microphone,
condenser microphone, or light modulation to produce an electrical
voltage signal from mechanical vibration.

3. Selection of Microphones

4. Selection of microphone is very important because the
microphone is the piece of gear closest to the source, it stands to
reason that selecting the right tool for the job can make all the
work easy.
There are basically three types of microphones.
Dynamic microphone Condenser microphone
Pick up patterns

5. DYNAMIC
MICROPHONE

7. Dynamic microphones are versatile and ideal for general-purpose use.
They use a simple design with few moving parts. 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.
The advantages of dynamic microphones are their
relatively low cost, high durability, and lack of need of power supply.
The main element commonly consists of a plastic-film diaphragm
connected to a coil of wire that is suspended in a permanent magnetic
field. Once sound hits the diaphragm, the whole assembly moves to
create a small electrical current.

8. CONDENSER
MICROPHONE

10. Condenser means capacitor, an electronic component which stores
energy in the form of an electrostatic field. The term condenser is
actually obsolete but has stuck as the name for this type of
microphone, which uses a capacitor to convert acoustical energy
into electrical energy.
Condenser microphones require power from a
battery or external source. The resulting audio signal is stronger
signal than that from a dynamic. Condensers also tend to be more
sensitive and responsive than dynamics, making them well-suited
to capturing subtle noises in a sound. They are not ideal for high-
volume work, as their sensitivity makes them prone to distort.

11. PICK UP PATTERNS
MICROPHONE

12. Unidirectional Microphone
It picks up sound directly in front
of the mics. Useful when the
sound source is at some distance
from the camcorder.

13. Bidirectional Microphone
It picks up the sound to the side
and in front of the mics’s head.
Mostly use in interviews , talk
shows , live shows etc.

14. Omnidirectional Microphones
Omnidirectional mic picks up sound waves
approaching the microphone from all
directions. While this is the most basic
pattern of the three, and the “purest”
sound, it is the least commonly used in the
studio. Consider this pattern when
capturing choral groups choirs, and the like,
or when natural room ambience is the goal.

15. Placement of Microphone

16. The golden rule of microphone placement is Get
the right distance .
In general, place the microphone as close as
practical to the sound source without getting so
close that you introduce unwanted effects .

17. .
 Proximity Effect
As you move a microphone closer to the source, bass
frequencies increase as distance decreases. This is least
apparent with omnidirectional mics, but must be
considered carefully with directional mics. Make sure you
place of your mics far enough away from the source to
avoid “howling” or excessive bass response.
There are some points to be considered while
placing the microphone which are given below

18. Mic-Stand Noise and Floor Rumble
Any vibrations traveling through a mic stand
will transfer through the microphone and into your
signal path. Keep cables attached or wrapped to
prevent them rattling against the mic stand. Position
your mic stand so it won’t transfer vibrations traveling
through the floor (foot stomps, kick drums, bass amps,
etc.). Due to their increased sensitivity, use shock
mounts when recording with condenser microphone.
Low cut can be useful for these situations as well.

19.  Phase Issues
This is a topic that will be covered more
closely in following topics, but here is an important tip:
When using multiple mics on the same source (acoustic
guitars, drum kits) roughly translated, if Microphone A
is 7 inches from the source, then Microphone B should be
at least 3 times that distance, or 21 inches, away from
Microphone A. This will help prevent phase issues
created by the time delay between the microphones.

20. Selection and placement of microphones for specific purposes :-
• NEWS – Unidirectional microphones / stand microphone.
• NEWS REEL – Unidirectional microphone.
• DRAMA – Bidirectional / hanging microphone.
• COMMENTARY – Hand held microphone.
• DOCUMENTARY – Bidirectional microphone.
• PHONE – IN PROGRAM – Hand held / bidirectional microphone.
• INTERVIEW – Bidirectional / hand held microphone.
• FIELD BASED PROGRAM - Condenser or dynamic microphone
• TALK – Bidirectional microphone.
SUMMARY