An introduction to microphones, types, Polar Pattern and Frequency

1. Microphones

2. Microphones:The technical Basics
Microphones are used whenever the sound of a voice or an instrument
needs to be reinforced – either on stage, in a rehearsal room, at
presentations or recording at home or in a studio.
There are three main technical characteristics that distinguish
microphones from each other.These characteristics are important to
understand to make the best choice for your needs:
Transducer type: How does the microphone physically pick up the
sound and convert it into an electrical signal?
Polar Pattern: From which direction does a microphone pick up the
sound?
Frequency Response: Is the output level or sensitivity of all frequencies
the same?
Introduction

3. Types of Microphones
1. Dynamic Microphones:- A physical cone acts like a lens to concentrate the
incoming sound waves. Dynamic microphones employ a diaphragm, a voice
coil and a magnet.The voice coil is surrounded by a magnetic field and is
attached to the rear of the diaphragm.The motion of the voice coil in this
magnetic field generates the electrical signal corresponding to the picked up
sound.
2. Ribbon Microphones:-A ribbon microphone is a type of dynamic microphone
that uses a thin electrically conducting ribbon placed between the poles of a
magnet. Ribbon microphones are typically bidirectional.They pick up sounds
from in front of the microphone and from the rear but not the side (90 degree
angle).
3. Condenser Microphones: Condenser microphones are based on an electrically-
charged diaphragm/ backplate assembly which forms a soundsensitive
capacitor. All condenser microphones need to be powered: either by batteries
in the microphone or by phantom power provided by a mixer. Condensers are
more sensitive and can provide a smoother, more natural sound, particularly at
higher frequencies.

4. Characteristics
• Robust and Durable
• They can be relatively inexpensive
• They are not sensitive to changes in humidity
• They don’t need internal or external power to operate
• They usually have a resonant peak in the mid frequency response
• Can be weak in the high-frequency response above 10 kHz
There are some common applications where you'll typically find dynamic
microphones:
• Sound Reinforcement
• Snare Drum Miking
• Guitar Miking
• Voiceovers And Broadcasts
Dynamic Microphones

5. Characteristics
• They have a relatively flat frequency response
• They have a better high frequency compared to Dynamic Microphones
• They don’t need internal or external power to operate
• They are somewhat fragile and require care while operating
• They are moderately inexpensive
Ribbon microphone applications include:
• Miking Cymbals
• Miking the bass
• Miking the piano
• Electric Guitars and Acoustic Guitars
• Brass Instruments.
Ribbon Microphones

6. Characteristics
• They have extended high and low frequency response
• Good once are sometimes expensive
• They require either internal or external power
• Large diaphragm models can be relatively bulky
• Low cost models can suffer from poor or inconsistent frequency response
• Humidity and temperature effect performance
Condenser microphone applications include
• Miking Cymbals
• Drum Overheads
• Piano
• Acoustic Guitar
• Vocals
• String Sections.
Condenser Microphones

7. Microphones: Polar pattern / Directionality
The polar pattern of a microphone is the sensitivity to sound relative
to the direction or angle from which the sound arrives, or easier
worded how well the microphone “hears“ sound from different
directions.
The most common types of directionality are: Omnidirectional,
Cardioid and Super cardioid
Polar Pattern/Directionality

8. • A cardioid microphone has the most sensitivity at the front and is
least sensitive at the back.
• It isolates from unwanted ambient sound and is much more
resistant to feedback than omnidirectional microphones.That
makes a cardioid microphone particularly suitable for loud
stages.
Cardiod

9. • Supercardioid microphones offer a narrower pickup than cardioids
and a greater rejection of ambient sound. But they also have
some pickup directly at the rear. Hence it is important to place
monitor speakers correctly.
• Supercardioids are most suitable when single sound sources need
to be picked up in loud environments.They are the most resistant
to feedback.
Supercardioid

10. • The omnidirectional microphone has equal output or sensitivity at all
angles, this means it picks up sound from all directions.Therefore the
microphone has not to be aimed in a certain direction which is helpful
especially with lavalier microphones. A disadvantage is that an omni
cannot be aimed away from undesired sources such as PA speakers which
may cause feedback.
Omnidirectional

11. • A microphone with a figure of eight polar pattern picks up the sound from
in front of the microphone and from the rear but not the side (90 degree
angle).
• Microphones with this Figure of Eight polar pattern are typically ribbon or
Large Diaphragm Microphones.
Figure of 8

12. Flat frequency response
All audible frequencies (20 Hz – 20 kHz) have the same
output level. This is most suitable for applications where the
sound source has to be reproduced without changing or
“coloring” the original sound, e.g. for recording.
Tailored frequency response
A tailored response is usually designed to enhance a sound
source in a particular application. For instance, a
microphone may have a peak in the 2 – 8 kHz range to
increase intelligibility for live vocals.
Frequency Response Curves
The frequency response is the output level or sensitivity of a microphone over its
operating range from lowest to highest frequencies. Generally two types exist

13. This construction of the Dynamic Microphone gives the dynamic mic its
robustness, but because the diaphragm is relatively heavy, that means that
it can't respond to sound waves quickly, which means its high frequency
response beyond 10 kHz is usually limited.
Frequency Response of Dynamic Microphones
(The above is a Frequency ResponseCurve is of a Shure SM 57 Instrument Dynamic Microphone)

14. Ribbon mics also have a smoother response than dynamics, since they don't have
a midrange presence peak like a dynamic microphone usually does.
Frequency Response of Ribbon Microphones
(The above is a Frequency ResponseCurve is of a Shure KSM353/EDPremier Bi-directional Ribbon Microphone)

15. 1) Small Diaphragm Condenser Microphones
The small diaphragm versions also have a slightly lower frequency response
Frequency Response of Condenser Microphones
(The above is a Frequency ResponseCurve is of a Shure KSM141Condenser Instrument Microphone)

16. 2 ) Large Diaphragm Condenser Microphones
A large diaphragm versions have a presence peak in the 8 to 12 kHz range,
which makes them a favorite for vocalists
Frequency Response of Condenser Microphones
(The above is a Frequency ResponseCurve is of a Shure KSM42Large Dual-DiaphragmVocal Microphone)