CHAPTER TWO

STUDIO MICROPHONES

Nitec in Digital Audio & Video Production Institute of Technical Education, College West

WHAT DO THESE HAVE IN COMMON?

OBJECTIVES � By the end of the chapter, you should be able to: ①  Describe the operating principles and the

characteristics of the dynamic and condenser microphones.

②  Describe the characteristics and common uses of microphones with different polar patterns.

③  Describe the common uses of different microphones. ④  List the key considerations when selecting microphones

for recording voice, musical instruments or sound effects.

⑤  Explain the purpose of using a pop filter.

WHAT ARE MICROPHONES?

� Microphones are transducers.

� A transducer converts one form of energy into another form of energy.

2.1 WHAT ARE MICROPHONES?

� Microphones are transducers.

� A transducer converts one form of energy into another form of energy.

� Examples of other transducers?

WHAT ARE MICROPHONES?

� Acoustic energy electrical energy.

� All mics have a diaphragm.

� A diaphragm is a thin piece of material that vibrates in response to sound waves to produce electric signals.

TYPES OF MICS

� There are two main types of studio microphones: ①  Dynamic Microphones

②  Condenser Microphones

2.1.1. DYNAMIC MICROPHONE

� Rugged build / durable.

� Does not require phantom power.

� Uses? - Mostly used for drums, guitar amplifiers, live-work.

(Image Source: Xmusic.ie, http://goo.gl/tdc1d)

2.1.1. DYNAMIC MICROPHONE

�  It is the most commonly used.

�  It is extremely durable and tough.

�  Inexpensive compared to a condenser microphone. �  Dynamic microphones can be used in many situations. �  Generally used in concerts and live performances. �  On stage, the dynamics are more useful than

condensers because they do not distort or feedback easily and require no power. (Image Source: Xmusic.ie, http://goo.gl/tdc1d)

2.1.1. DYNAMIC MICROPHONE

� The diaphragm has a coil attached to it that moves within a magnetic field.

� This generates an electrical current (audio signal).

� Diaphragm + coil = heavy

� It is less sensitive than a condenser microphone.

(Image Source: Burning Groove, http://goo.gl/Nys5V)

2.1.1. DYNAMIC MICROPHONE

Disadvantages of dynamic microphones: � Does not capture high frequencies well

� Heavy components (coil + diaphragm) slows down its reaction to sound.

� High frequencies with short wavelengths require the diaphragm and coil to vibrate very quickly for an accurate sound to be transmitted.

� Does not capture transients accurately � Sounds which are very short and fast (transients) also

require a diaphragm that can react quickly

2.1.2. CONDENSER MICROPHONES

�  The standard for most studio applications that require maximum clarity, subtlety and detail in the recording.

�  These can be used for vocals, acoustic instruments, string sections, ambient room sound or stereo overheads on a drum kit.

�  The condenser is much more sensitive than dynamic.

�  The condenser has a much more sensitive frequency response and can pick up the subtle nuances of a performance more effectively.

(Image Source: Neumann, http://goo.gl/grW27)

2.1.2. CONDENSER MICROPHONES

� Has an electrically charged diaphragm and backplate.

� Acoustic energy (sound waves) sets this diaphragm into motion.

� Changes in the electric field produce the electrical signal.

(Image Source: Burning Groove, http://goo.gl/O0pJS)

2.1.2. CONDENSER MICROPHONES

� The diaphragm can be made from very thin material.

� This gives it a high sensitivity.

� Sounds more natural than a Dynamic microphone.

(Image Source: Sound on Sound, http://goo.gl/gFdsz)

2.1.2. CONDENSER MICROPHONES

Advantages:

�  More sensitive frequency response.

�  Can pick up quieter sounds.

�  More effective in capturing transients.

Disadvantages: �  Much more fragile than dynamic

microphones.

�  Rather expensive.

�  Cannot handle high SPLs. �  May result in distorted/clipped

recordings �  May damage the condenser mic

ACTIVITY

(Image Source: Hasbro, http://goo.gl/127En)

‘Microphone Taboo’

ACTIVITY

(Image Source: Hasbro, http://goo.gl/127En)

Game rules: PIZZA

ITALIAN

PEPPERONI

CHEESE

Taboo Card Sample

ACTIVITY [15 MINS] Game rules:

AUDIO

SOUND

NOISE

RECORD

Taboo Card Example � Split up into 4 teams

� T1 vs T2 / T3 vs T4

� Describe the main word without using the 3 taboo words at the bottom.

� One minute per round.

RECAP

� So far, we have learned: � What microphones are – transducers � Types of microphones – dynamic &

condenser � How dynamic & condenser microphones

work � Properties???

2.2 DIRECTIONAL PROPERTIES

� All microphones have a property known as directionality.

� This describes the microphone’s sensitivity to sound from various directions.

2.2 DIRECTIONAL PROPERTIES

Omnidirectional }

Unidirectional

Bidirectional

� The types of directionality are divided into three main categories:

(Source: Performing Musician, http://goo.gl/46QCw)

MICROPHONE PICK-UP PATTERNS

(Source: I Like Mics, http://goo.gl/66ttb)

� A polar pattern is a graph to show directional properties of microphones.

� Often found in microphone user manuals or promo material.

2.2.1 OMNIDIRECTIONAL

(Source: Wikipedia, http://goo.gl/vp6kh)

� Captures sound equally from all directions.

� Uses: v Capturing ambience v When sound is coming from

many directions v When sound source is moving

while microphone remains fixed.

2.2.2 UNIDIRECTIONAL: CARDIOD

(Source: Wikipedia, http://goo.gl/gDZD1)

� Sound is picked up mostly from the front.

� Uses: v Emphasizing sound

from the direction the microphone is pointed.

2.2.3 UNIDIRECTIONAL: SUPERCARDIOD

(Source: Wikipedia, http://goo.gl/rRMSR)

� Exaggerated version of cardioid pattern.

� Very directional; eliminates most sound from sides & rear.

� Also called ‘Shotgun’ microphones.

� Uses: v Isolating sounds from a subject

when there is a lot of ambient noise

v Picking up sound from a distance.

2.2.4 BIDIRECTIONAL: FIGURE-OF-8 PATTERN

(Source: Wikipedia, http://goo.gl/Vld5j)

� Uses a figure-of-8 pattern to pick up sounds equally from two opposite directions.

� Uses: v Not many applications for

bidirectional pattern v Interview, with two people facing

each other (microphone in between).

v Mid-Side / MS Stereo Technique.

2.2.5 VARIABLE DIRECTION

(Source: Stephen Caulfield, http://goo.gl/vKZUC)

� Allows you to vary the directional properties; can select omni, cardioid or figure-of-8.

� Sometimes found on video

camera microphones: v Adjust directionality

according to zoom.

(Source: Long McQuade, http://goo.gl/J33wv)

VIDEO: PICK-UP PATTERNS

�  Video!

(Source: YouTube, http://youtu.be/8fEAelxfjdc)

2.3 OTHER MICROPHONES

2.3.1 Pressure Zone Microphones (PZM) �  Consists of an omni-directional microphone

capsule mounted on a plate of around 6 inches (15cm) square or 6 inches in diameter pointing directly at the plate and is around 2 or 3 millimeters.

�  The plate is intended to be placed on a large flat surface such as a wall or floor.

�  Its polar response is hemispherical.

�  PZMs are used to record grand pianos (placed on the underside of the piano lid), dramas or operas (on the stage floor), or ambience miking (on the floor or walls).

2.3 OTHER MICROPHONES

2.3.2 Lapel (Lavalier) Microphone �  Widely used for television, theatre and

public-speaking because it allows for hands-free operation.

�  Commonly, lapel mics are omnidirectional so the sound remains consistent regardless of the direction it is facing.

�  The lapel microphone is generally used with a wireless transmission system. The mic is connected to a radio frequency transmitter in a pocket or clipped to a belt.

�  A disadvantage of the lapel mic is the possibility of noise from the user’s clothing.

2.3.3 STEREO MICROPHONE TECHNIQUES

True-stereo miking techniques are utilized to convey:

�  The depth or distance of each sound source

�  The distance of the sounds from the listener (perspective)

�  The spatial sense of the acoustic environment, the ambience or room.

The easiest and most versatile way to capture sound in stereo is to use two microphones. However, accurate positioning of the two microphones is important in order to get a true stereo image.

2.3.3 STEREO MICROPHONE TECHNIQUES

There are 4 types of stereo microphone techniques we will learn: � XY Configuration � ORTF Configuration � A/B or Spaced Pair � Mid-Side or MS Technique

2.3.3.1 XY CONFIGURATION �  Two cardioid microphones placed at a 90 degree angle to

each other.

�  In this technique, the microphone on the left is wired to the right channel, and vice versa.

�  This technique is considered the perfect way to record in stereo.

�  With this technique, you will get a recording that's very focused, with a tight low-end response.

�  You'll lose a little depth, but that's made up for in the lack of ambient information.

�  This technique is best used if you're in a difficult-sounding room, and need to "zoom in" on the sound as best as possible. When used with figure-8 (bidirectional) microphones, XY is called the Blumlein Technique.

2.3.3.2. ORTF CONFIGURATION � ORTF uses two cardioids microphones

spaced 17 centimeters. � With the angle between the microphone

bodies at 110 degrees. � ORTF works well in poor acoustical

environments. � Using ORTF up close to a sound source

could result in too much off-axis pickup. � ORTF is well-suited for concert taping.

2.3.3.3. A/B OR SPACED PAIR �  A/B is the simplest stereo technique to use.

�  Two microphones are pointed straight ahead at a source.

�  This technique sounds good on acoustic guitar.

�  There's not much stereo image.

�  A/B is the preferred method of tapers who stack tape - taping close to the speakers to get a cleaner sound.

�  A/B isn't as useful for taping further back, as a good stereo image is necessary for full reproduction of the event.

2.3.3.4. ‘MID-SIDE’ OR MS TECHNIQUE

�  You can make your own M-S matrix with one cardioid mic and a figure-8 pattern mic.

�  The cardioid mic faces forward and the figure-8

mic is set directly on top.

�  The lobes of the 8 should be positioned at 90 degrees to left and right.

�  These signals can be captured on a two-track recorder.

�  One channel acting as "mid," the other as "side." The signals can be decoded later in your digital editor.

2.3.3.5. STEREO MICROPHONES

�  Stereo Microphones are available in

which two microphones are built into a single casing.

�  One capsule is rotatable with respect to the other so that the angle between the two can be adjusted.

�  Also, each capsule can be switched to

give any desired polar response.

(Source: http://goo.gl/1mwq9)

ACTIVITY

(Image Source: Hasbro, http://goo.gl/127En)

‘Pick-up Pattern Taboo’

ACTIVITY [15 MINS] Game rules:

AUDIO

SOUND

NOISE

RECORD

Taboo Card Example � Split up into 4 teams

� T1 vs T2 / T3 vs T4

� Describe the main word without using the 3 taboo words at the bottom.

� One minute per round.

ACTIVITY SHEET [15 MINS]

� Get into pairs. 1.  Match the characteristics and descriptions

to the correct type of microphone.

2.  Draw and name the three main types of microphone directional characteristics.

ACTIVITY SHEET [15 MINS]

� Time is up!

� Switch partners and give feedback to each other.

SHORT QUIZ

� 15 minutes.

� Individual work.

� Answer all ten questions in MCQ.

� After time is up, get into pairs and discuss answers.

CONCLUSION

� What have we learned today? v Microphones, transducers, dynamic &

condenser microphones (and how they work) – three differences?

v Directionality, pick-up patterns & polar patterns – three main types of patterns?

Thank you!

REFERENCES

Microphone Clipart

EasyVectors, http://goo.gl/6tC4u

Blank Canvas

AdventureTime.Wikia.com, http://goo.gl/jvA5n

Paintbrushes

Picipedia.com, http://goo.gl/XCw7o

Guitar Humbucker

JOKO471, http://goo.gl/z5VfT

Headphones TivoliHifi, http://goo.gl/Y6D2l Lightbulb CyberCauldron, http://goo.gl/ivrgS Windmill, DarkRoastedBlend, http://goo.gl/NYgFC Street Signs, Singapore Shots, http://goo.gl/Aso93