Video Production Online Curriculum

Instructional module 6:  The Audio Engineer - Microphones, Music & Sound Effects

Content:  Part 1 = Careers-in-Television | Part 2 = Lesson A - Part 2 = Lesson B | Part 3 = Project

This lesson has two parts: Part A deals with audio equipment , Part B covers music, sound effects, and copyright issues.

"Video projects stand or fall on the basis of their audio." **

Audio is an important part of a video production.  In fact, high-quality audio can improve an average video production so it becomes quite good, while poor quality audio can turn a very good video into a pretty bad production!

Audio vs Sound

Sometimes we use the words "sound" and "audio" interchangably, but "sound" refers to the actual physical vibrations(sound waves) transmitted through the air, while "audio" refers to the equipment used to transmit, receive, or reproduce sound, such as microphones, amplifiers, speakers, and music equipment.

The Audio Engineer is responsible for all the audio on the video production, including any background or add-in music and sound effects.  The Audio Engineer sets up all audio equipment, including microphones used by the Talent, and during the production manages all incoming and outgoing audio from the Audio Station in the video production Booth.  The Audio Engineer can also act as Booth/Tech Director.

There are three main components of audio-for-video production:

1. a sound receiver, i.e., a microphone  - converts sound waves into electrical energy, called an audio signal, which is sent through a cable to...
2. an audio receiver  - receives the electrical audio signals, balances them in relation to each other, and feeds them out through cables to...
3. a transmitter unit - converts electrical audio signals back into sound waves and sends them out to the audience. 

These three main audio components may be housed in a single unit, as with a videocamcorder, or there may be several pieces of equipment, each of which performs part of the process.  In this lesson we first learn about the equipment used for each of the three components of audio-for-video production, and then, in the second part, we discuss music and sound effects, during which we also examine the important issue of copyright.

Microphones

The microphone is the most important audio component because it determines the quality of the audio input.  If you don't use the correct type of microphone for what you need, then your audio will be poor, no matter how good the other components are.  By learning the difference between types of microphones, you can choose the correct one for the needs of your video production, in order to have the highest sound quality possible.

Video camcorders have a built-in microphone which works fine for home videos; however, for a quality video production, sound is captured directly from the Talent through professional external microphones.  Not only does this improve the sound quality, but it also allows us to add music and sound effects during and/or after the videorecording process through an Audio Mixer.  The microphones we use for video production have 2 basic characteristics: physical form & directionality. 

Physical Form
Physical form is what the microphone looks like and where it is placed in order to pick up sound.  There are four forms of microphones:

• Handheld - the most commonly seen microphone; can be inserted into a floor or desktop stand to leave the hands free.  The handheld mic is positioned 6-12 inches from the Talent's mouth, pointed at a 45° angle toward the mouth.
   
• Lavalier - a small microphone that clips on the speaker's clothing; more inconspicuous and flexible than a handheld, it is used when the Talent needs to use hands to gesture or display, or to move around the studio area.  The lavalier is placed outside the clothing about 6-8 inches below the person's chin.
   
• Shotgun - a long tubular, very sensitive microphone used to pick up sound in a very tightly focused area from a longer distance away; shotgun mics are used when you don't want a microphone to appear on camera.  A shotgun mic is positioned a little above, below or to the side, about 3-4 feet away, and pointed directly at the Talent.  For more precise pickup at longer distances, a parabolic dish can be mounted around the microphone to capture more sound.
   
• Surface or PZM Boundary (also called "desk" microphone) - a low-contour microphone that sets on a flat surface to pick up sound from a group of people; sound waves are also picked up by being reflected off the flat surface on which the mic is placed. 

Directionality
Directionality is how a microphone picks up sound from different directions and angles; directionality is also called the "pick-up pattern."  Some microphones pick up sound equally well from all directions and some microphones only pick up sounds from a particular direction.  Microphone directionality is of 2 types:

• Unidirectional - uni means one, so a unidirectional microphone picks up sound from only one direction--the area directly in front of it.  Unidirectional mics are often called cardioid mics, because the pattern of sound pickup near the front of the mic is heart-shaped (cardio is the Greek word for heart).  The disadvantage of a unidirectional mic is that the Talent must keep the mic pointed directly at their mouth to insure good sound pickup.  Handheld micriphones and shotgun microphones are usually unidirectional.
   
• Omnidirectional - omni means all, so an omnidirectional microphone picks up sound equally well from all around itself--front, sides, above, below, even behind.  These are excellent to use for interviews, since they pick up sound equally well from both persons when held between them.  The disadvantage of omnidirectional mics is that they may also pick up background noises or feedback sound reflected off walls and ceiling in a small, hard-surfaced room.  Desk microphones and lavalier microphones are usually omnidirectional.

Ask Ms P for the Videomaker DVD Basics of Videography.  Watch Title 7, Chapter 3: “Microphone Types.”

Cabled or Wireless?
The method the microphone uses to send the audio signal to the audio receiver can also have an impact on your video production.  A cabled microphone sends the audio signal to the audio receiver through a cable.  Cables come in varying lengths--we have cables as short as 3-feet and as long as 100-feet, but most of our cables are 25-feet.  Using cabled microphones is fine for stationary video productions, such as a news broadcast, but using a wireless microphone gives the Talent more freedom to gesture and to move around the studio area, a real benefit for more elaborate video productions.

A wireless microphone is like a miniature radio station--it converts sound into an electrical audio signal and then converts that signal into a radio signal at a certain frequency, which is then sent through the air.  A wireless mic receiver tuned to the same frequency as the microphone picks up the radio signal, converts it back into an electrical audio signal, and feeds it into the audio receiver through a cable (so the mic receiver is usually located near the audio receiver).  (For on-location videorecording there are wireless mic receivers that plug directly into a videocamcorder that accepts an external microphone!)  Each wireless microphone at a particular location operates on a different frequency, so they don't interfere with each other, just as two radion stations in the same city can't broadcast on the same channel, thus each wireless microphone can be used only with its own matching microphone receiver.

During pre-production, the Audio Engineer works with the Studio Director to choose microphones appropriate to the script and activities of the production, and then sets up the microphones for the best quality of sound pickup, within the confines of the studio or location Set. 

Cable Connectors

Since we've mentioned cables, this is a good time to talk about the different types of connectors on the ends of the cables we use with our audio (and video) equipment.  There are four types of audio connectors:

• XLR - low-voltage connectors for microphones and microphone cables
• 1/4" phone - high-voltage connectors for auxiliary equipment and speaker cables
• 1/8" mini - small phone-type connectors for headphone cables, such as for your Walkman or computer
• RCA phono - on cables that connect audio & video equipment such as phonographs, DVD/VCRs, TV monitors, amplifiers, and sub-band unit

The Audio Mixer

In our video production lab, the audio receiver component is an Audio Mixer that receives signals from different audio sources (microphones, tape/CD players, DVD/VCRs, videocamcorders), combines or "mixes" the signals together into a single signal, and then sends that signal out to one or more transmitter units (VCR, TV/video monitor, computer, amplifier &speakers, sub-band broadcast unit).  The Audio Mixer has so many buttons and other controls that it can be a little scary at first; however, many of these are duplicated for each audio input source, and once you learn what they are for and how they work, it isn't so hard at all.

The Audio Mixer has input sockets that allow the different types of cable connectors to be plugged into the Mixer: mic-level inputs accept low-voltage XLR microphone connectors; line-level inputs accept higher voltage phone and phono connectors from other audio equipment.  Each of these input sources is a single "channel" on the Audio Mixer (much as each TV station comes in on a single channel to your TV).

The various controls for each channel run vertically down the mixer under the input sockets in the following order, with the most often used controls lowest and closest to the operator:

• GAIN (white knobs on the Mackie) - adjusts level of the audio signal as it enters the input channel; set for type of signal input, mic or line, and leave it.
• AUX (red knobs on Mackie) - sends the channel's audio signal to an "auxiliary" piece of equipment that is different than the main mix output. The AUX signal can go one way into the AUX piece, or in case of a sound effects generator, can return the signal to the AUX return (located at the far right of the AUX panel).  We don't really use AUX at this time.
• EQ (blue knobs on Mackie) - Equalization, which means increasing or decreasing different frequencies of the signal.  You can make a high squeaky voice sound lower or a low rumbling voice sound higher!  EQ can also help reduce screechy feedback.  Turning knob left cuts that frequency's signal level; turning right boosts it.
• PAN (black knobs on Mackie) - basically to balance stereo output; usually set in the center and leave it.
• FADER or slider (white rectangular button at bottom of Mackie) - adds the signal and adjusts it's volume to the main mix output.

The Mackie uses a "U" for the optimal setting of all controls; this stands for "unity," meaning the signal has been neither increased or decreased by the mixer and is coming through exactly as it is sent from the source.

Ask Ms P for the Videomaker DVD Basics of Videography.  Watch Title 7, Chapter 7: “Mixing & Editing Audio”; 
stop @ the beginning of "Nonlinear Editing."

Main Mixer Output

The best way to check the levels of different equipment is to send a 0dB audio test tone from the mixer and measure it at the next point in the chain.

During production, the Audio Engineer monitors sound levels from the microphones, and runs the sound mixer and other audio equipment in the Booth.   

**Information in this module taken from:
Lyons, Christopher. Audio Systems Guide for Video Production. Online: Shure Educational Publication, 2002;
 http://www.shure.com/ProAudio/TechLibrary/EducationalArticles/index.htm

This is the end of Module 6, Part 2, Lesson A about audio equipment. Continue on to Part 2, Lesson B about music, sound effects, copyright, and more of the Audio Engineer's responsibilities.

An additional website with in-depth information about audio equipment:
Media College - Audio Tutorials
Media College - How to Use Microphones
Media College - Choosing the Right Microphone