Discuss about What is Microphone with its uses and types. In addition polar patterns and its importance are briefed.

1. MICROPHONES
AND
ITS TYPES
RIJITHA R
ASSISTANT PROFESSOR
Department of Media Studies

2. What is a Microphone?
• A small, portable assembly for the pick-up and
conversion of sound into electrical energy.

3. Types of Microphones
• Dynamic
• Ribbon
• Condenser
• Lavalier Mic

4. 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.
• Dynamic microphones are probably the most common and versatile
microphones for general recording uses.
• They are relatively simply designed with few moving parts involved.
• These microphones are also more appropriate to handle high volume
levels. For example, they will deal better with certain instruments or
amplifiers.
• They don’s contain an internal amplifier and do not have need of batteries
or external power

5. • When a magnet is moved near a coil of wire an electrical current is
generated in the wire.
• This principal of using an electromagnet is how a dynamic microphone
works.
• It uses a wire coil and magnet to create the audio signal.
• There is a diaphragm (A Loudspeaker that turns electrical signal to
sound waves) attached to the coil in the microphone.
• When this vibrates (due to sound waves), the coil moves backwards and
forwards past the magnet.

6. 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

7. Dynamic Microphone

8. 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).
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

9. Ribbon microphone applications include:
• •Miking Cymbals
• •Miking the bass
• •Miking the piano
• •Electric Guitars and Acoustic Guitars
• •Brass Instruments.

10. Ribbon Mic

11. • Condenser microphones are based on an electrically-charged diaphragm/
back-plate assembly which forms a sound sensitive 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.
• Capacitor microphones (also known as condenser microphones), require a
battery or some other source of external power.
• Using a capacitor microphone will give a stronger audio signal than that of
a dynamic microphone.
• These types of microphones are also more sensitive and responsive than
dynamic microphones.
• This makes them the best choice of microphone when it comes to recording
subtle elements in sound.
• However, due to there sensitivity, they are not the right choice of
microphones for high volume recordings as they are likely to distort.
Condenser Microphones

12. • This type of microphone works by having two plates with a voltage
between them.
• One of the plates is made of an extremely light material that will act as the
diaphragm. When hit by sound waves, the diaphragm will vibrate and
change the distance between the two plates, consequently changing the
capacitance.

13. 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

14. Condenser Microphone

15. Lavalier mic
• Also known as lapel mic, the lavalier mic is a tiny thing that is typically
clipped to a shirt, jacket or tie. You can also attach them with tiepins,
magnets etc .
• Because they're so small, they often go unnoticed and are a favourite for
news anchors and interview subjects.
• While black is the most common color, some lavaliers are available in
white, beige and brown.
• Talk shows and news networks often stock several in different colors to
match the clothing of their hosts and guests.
• When using a lavalier mic outside, you may need to add a windscreen to
minimize wind noise.

16. • This will add to the profile of the mic and might eliminate the advantage of
the small size. In these cases, it's common to attach the mic under thin
clothing such as a shirt or blouse.
• Another lavalier trick is using the body of the subject as a shield - to block
either wind or background noise.
• With the wind or distracting sounds to the back of the talent, you'll capture
clearer sound and simplify your work in editing.
• final tip: keep an eye on the mic clip. These things go missing faster than
your cell phone or TV remote and they're an essential part of the kit.
• In addition, you can't just go to the local electronics store and buy a
replacement.

17. Lavalier

18. What is a Pick up pattern
• A film is only as good as its audio.
• While it can be easy to get captivated by the visual side of a film, audio should
be high on the priority list of any director or producer.
• Bad audio can quickly turn off an already distracted audience, so it’s important
to pick the right mic for the job.
• 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
• Let’s take a look at six essential microphone pickup patterns that every
filmmaker should know.

19. Pickup patterns
• Omnidirectional
• Uni Directional
• Bi Directional
• Cardioid
• Hyper Cardioid
• Super Cardioid

20. Omni directional
• Perfect for: interviews, moving subjects
• 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 (Public address) speakers which may cause feedback

21. Uni Directional
• It is otherwise called as LOBAR.
• Perfect for: narrative film, controlled sets.
• It Picks up sound predominantly from one direction.
• Unidirectional Microphones are microphones that only pick up sound with
high gain from a specific side or direction of the microphone.
• If a user is speaking into a unidirectional microphone, he must speak into
correct side, normally called the voice side, of the microphone in order to
get good gain on the recording.

22. • The polar plot shows that the
microphone has the highest gain
when the sound source is directly in
front of it, which is shown at the 0
degree reference point.
• At this 0 degree point, we can see
the gain is 11dB.
• Now as the sound source is rotated
so that it is at the sides, the gain of
the microphone decreases because
it is not as effective at picking up
sounds from the sides.
• As the sound source gets rotated
more to the sides toward the rear,
the gain drops more and more.
• And finally from the rear, the
microphone picks up the lowest
gain, which in this case is about -
28dB.
• This shows again that unidirectional
microphones are most effective at
picking up sounds from the front
while it is much less effective at
picking up sounds from the sides
and rear.

23. • Unidirectional microphones are used in applications where the target sound
source to be recorded is directly in front of the microphone, and all other
sounds in the room that may be on the sides and rear do not want to be
recorded.
• Thus, unidirectional microphones have great application when a sound
source can stay stationary in front of the microphone to record only that
sound source and no other.

24. Bi Directional/ Figure of 8
• 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.
Bidirectional microphones are used in applications where sound is recorded from
the front of the micrphone and back of the microphone, but not the sides.
An example of this is a Q&A lecture or presentation, where a professor gives a
lecture to an audience and accepts questions from them. A microphone needs to
pick up the speech of professor from the front and the questions asked from the
back in the audience. This is a practical example of where bidirectional
microphones are needed.

25. Bi Directional/ Figure of 8

26. Cardioid Mics
• Cardioid Microphones are microphones that pick up sounds with high gain
from the front and sides but poorly from the rear. Cardioid microphones are
named for the fact that their directional sound pick-up is roughly heart-shaped
in nature.
• The image to the right shows a typical polar plot response of a cardioid
microphone. Polar plots show the gain of a microphone for all the various
directions that it points to in relation a fixed sound source.
• The sound source stays in the same position but the microphone is rotated
around from 0° to 360°.
• By doing this test, we can know what gain the microphone records at all of the
various directions that it points.
• A cardioid microphone basically has a polar plot response that is heart-shaped
in nature. It picks up sound with high gain, or sensitivity, from the front and
sides, but steeply lower when sounds are from the rear.

27. Cardioid microphones are used in applications where sound needs to be
picked up from the front and sides but not the rear.
An example of this may be musical performance where a singer may be
singing in the front, a band playing instruments on the sides, with an audience
of viewers in the back. In a scenario, it may be desired only to record the
music.
The singer in front and band on the sides, but not the audience in the rear. For
this type of scenario, cardioid microphones have great use and applicaton.

28. Super cardioid
• 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.
• Supercardioids are most suitable when single sound sources need to be
picked up in loud environments, they are the most resistant to feedback.
• Supercardioid pickup patterns are typically only found in shotgun mics
which are used on boom poles or mounted to the top of a camera.
• It should be noted that a super cardioid pickup pattern does pickup some
audio from behind the microphone.

29. IN STUDIO
• The very narrow supercardioid
pickup pattern is great for capturing
a single instrument or isolating a
singer’s voice from any
accompanying instruments.
• But make sure the recordist doesn’t
move around too much—the tight
pattern will reject sound if the
performer is off-axis.
ONSTAGE
• Because they’re even more focused
than cardioids, supercardioid mics
generate much less feedback.
• This makes them ideal for capturing
vocals or isolating a particular
instrument in extremely loud stage
environments.
• Just remember, that little sensitive
spot on the rear of the mic will
pickup sound if you’re not careful.
• In contrast to cardioid
microphones, it is not
recommended to position the
monitor in front of the microphone.
• Position each monitor 120 degrees
off-axis to avoid unwanted
feedback. Aim any monitors away
from the mic to minimize noise
bleed.

30. Hyper Cardioid
• Hypercardioid patterns are similar to cardioid patterns in that the primary
sensitivity is in the front of the microphone.
• They differ, however, in that the point of least sensitivity is at the 150 – 160
and 200 – 210 degree positions (as opposed to directly behind the
microphone in a cardioid pattern).
• Hypercardioid microphones are thus considered even more directional than
cardioid microphones because they have less sensitivity at their sides and
only slightly more directly behind.
• Hypercardioid microphones are frequently used in situations where a lot of
isolation is desired between sound sources.

31. • It Isolates the sound from a subject or direction when there is a lot of
ambient noise; Picking up sound from a subject at a distance.

32. Polar patterns…

33. THANK YOU