This document provides an overview of microphones, including their basic function, history, types, and key considerations for choosing a microphone. It begins with definitions of microphones and a brief history starting with Alexander Graham Bell's invention in 1876. It then discusses the rise of broadcasting in the 1920s and need for better microphones. The main microphone types - dynamic, condenser, and ribbon - are outlined. Additional sections cover lavalier microphones, phantom power, differences between dynamic and condenser microphones, polar pickup patterns, and factors to consider when choosing a microphone like decibel scale, frequency response, and equivalent noise level.

1. Microphone
Essentials

2. Basics

3. What is a microphone?
A microphone is a transducer that converts
acoustic energy to electrical energy.
It has many uses in today's world from
medicine to musical recording.
It reacts to a pressure input by use of a
diaphragm.

4. History

5. The Invention of the Microphone
1876 – Alexander Graham Bell
1878 – Hughes (First use of term ‘microphone’)
(actually, a carbon microphone )
- Used for telephony
- Use pressure which get converted to resistance
- And done well since then

6. 1920’s
The Rise of Broadcasting

7. Microphones used for telephony
had limited dynamic range and
high distortion.
Commercial broadcasting required
better microphones.

8. Microphone
Types

9. Dynamic Microphones
1. Dynamic moving coil microphones employ a coil
of wires attached to a diaphragm, which is
suspended within a magnetic field.
2. Acoustical vibrations cause the diaphragm and
the coil to vibrate within this magnetic field,
creating an AC (alternating current.)
3. This current electrically represents the audio
signal.

10. Condenser Microphones
1. Condenser microphones use two adjacent
plates. One is stationary, while the other, a
diaphragm, vibrates to incoming acoustic signal.
2. These two plates are charged with a constant
voltage - phantom power. As the distance
between the stationary plate and diaphragm
varies with incoming vibrations, a varying
electrical current is generated.

11. Ribbon Microphones
1.
2.
3.
4.
Again principle of induction is used
Ribbon (Induction) is used as diaphragm
Oscillates between magnetic poles
Bi-directional

12. Lavalier
Lavalier
microphones
are
small,
lightweight microphones designed to be
attached under the chin of the speaker.
Attached to the talker’s clothing in such a
manner that they will not move and
produce rustling noises.
Common in television and film production
because they are easy to conceal.

13. Phantom
Power

14. Phantom power is a method of
powering a condenser microphone
using another device. For example, the
cable from the microphone to the audio
mixer or videotape recorder could carry
power as well as audio signals. If you
are able to provide a microphone
phantom power, you will not need
batteries!

15. Dynamic V/s Condenser
Microphones

16. Dynamic Microphones
Actual energy to
energy transfer 1:1
Accurate representation
Low cost
Less sensitive (smaller
sound field)
More durable than
other types of
microphones
Condenser Microphones
Amplified transfer of
energy is more than 1
Extremely accurate
Higher cost
Very sensitive (larger
sound field)
Less durable (prone to
humidity and shock)

17. Microphones
Polar Pick-up Pattern

18. A polar pick up pattern is a graph used to show the
microphone’s sensitivity to sound coming from
different directions.
Example

19. Microphones : Types of Polar Pattern
Omni directional
Bi-directional
Cardioid
Super Cardioid
Hyper Cardioid

20. How to Choose
Microphones

21. Decibel (dB) scale
Measures how sensitive the
microphone is
Frequency Response
“Bandwidth“ of microphone
On-axis response
Response to sound coming
directly to the microphone
Off-axis responses
Response to sound coming
from all angles
Diffuse field response
Response to sound coming
from reflections
Equivalent noise level
Noise from microphone itself
(good if <15db)
Sensitivity
What voltage a microphone
will produce at a certain sound
pressure level

22. Thank You