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Sound Equipment For Studios and Concerts

Brian Laakso • Technology • January 26, 2015

Sound Equipment for Studios and ConcertsThis exciting lesson plan in understanding and using sound equipment for your concerts and studio projects is excerpted from Music Tech 101 – A Group Study Course in Modern Music Production using Audio Technology, by Brian Laakso, a new curriculum for teaching music technology programs in high school, available January 2015 from Alfred Publishing, published in cooperation with TI:ME – The Technology Institute for Music Educators.

The Foundations

You need a basic understanding of sound equipment, its components, and its functions to appreciate both studio recording and live concerts.

Before diving into specifics about various pieces of equipment, it’s important to understand the signal flow in most sound-system setups.

Step 1: Sound is created by a singer or an instrument.

Step 2: The sound is captured and changed to electricity
 by a microphone.

Step 3: Microphones collectively carry that electricity to a
 mixer, where it is blended.

Step 4: The mixer sends the blended electrical signal to
 an amplifier.

Step 5: The amplifier increases the voltage of the electrical
 signal, which it sends to the speaker.

Step 6: Speakers convert the electricity back into sound.

Step 7: The sound vibrations travel through the air to our ears.

Step 8: Our eardrums in turn vibrate and change the sound
 into an electrical signal, which is perceived by our brain as
 sound.

Shure SM58 handheld mic

Now that you understand the signal flow, let’s explore some of the various components of the sound system.

The primary job of a microphone is to change sound waves into electrical current via a small membrane inside the microphone that vibrates in sympathy with soundwaves bumping into it. There are many types of microphones. Some basic types include handheld, lavalier (which can be clipped onto a lapel or collar), headset (useful onstage so that a singer can dance and move hands-free), boom (a large fuzzy mic that is held above the heads of TV and movie actors), and wireless (which can be any of the aforementioned types). More specific types of mics also exist, such as carbon, dynamic, and ribbon; you can study their respective directional response patterns.

A couple of popular microphones used for live sound applications include the Shure SM57 and SM58. These mics sound great and are extremely rugged — they are constructed  to withstand use night after night. The membrane, electrical transducer, and wiring are protected by a small, strong steel-mesh cage lined with foam. This windscreen protects the microphone from rough contact, saliva, drops, and so on.

A mixer’s primary job is to blend multiple incoming microphone signals into a single output and to give a lot of control over those signals — a mixer can manage volume, timbre, routing, and other aspects of incoming sound. A mixing console has knobs to control equalization (treble/bass), special effects (reverb, delay, and so on), pan (left versus right speakers), monitor sends (special speakers located for performers to hear themselves), and mic sensitivity (how “hot” the mic is). Also, a mixer usually has a row of white sliders, known as faders, which control the overall volume and blending of the mics and instruments. The person in charge of the mixer is called an engineer, although in live settings that person might be called a front-of-house engineer or a monitor engineer. The engineer is responsible for balancing all incoming sounds, making the necessary adjustments, and making the musicians sound great!

Rack of Crown amplifiersAn amplifier’s primary job is to increase the power of an electrical signal. The signal, on its way from the mixer to the speakers, is given a sharp “boost” by the amp. The power of this boost is determined by the number of watts the amp can handle. Like microphones, there are many types of amps, but in this chapter we are limiting ourselves to power amplifiers used for making music louder. The more watts an amp is rated to handle, the louder it can usually make the sound. Car stereos, coming straight from the factory without modification, usually run from approximately 40 to 100 watts. Powerful home stereos might be rated from 100 to 500 watts — plenty for a living room or garage party. Small concert clubs may use thousands of watts, while large arenas or outdoor venues may pump out 10,000 watts or more.

Often amplifiers are used cooperatively — anywhere from two to two dozen amps might be divided to drive several kinds of speakers at once. They might be divided to power only one side of the house sound system. Also, they might be divided using a splitter called a crossover to do a special job, such as powering tweeters (speakers that reproduce only high sounds), midranges (speakers that reproduce sounds in the middle range of hearing), and subwoofers (speakers that produce the lowest audible sounds).

A speaker’s primary job is to change the electrical signal back into soundwaves. The electrical signal travels through a voice coil electromagnet situated between the poles of a magnet, which in turn vibrates a paper cone. The cone then pushes and pulls the air in the club, automobile, hall, or room back and forth, until the vibrations reach the listeners’ eardrums. The larger the cone is, the lower the sounds it can produce. A special type of speaker used onstage in live concerts is the monitor wedge. This speaker is wedge-shaped, usually angled up toward a singer or an instrumentalist, and allows the performer to hear more clearly onstage.

The sound engineer’s primary concern is the risk of feedback, which is basically the terrible sound of audio getting trapped in a loop within the sound system. Feedback typically happens when a mic is angled toward a speaker. The mic picks up a frequency, which runs through the system and is amplified, coming out of the speaker at a louder volume. This louder tone is then picked up by the mic again, is run through the sound system a second time, and comes out the speaker twice as loud. The unwanted frequency continues to cycle until the mic is redirected. Sometimes it can be controlled by adjusting the equalizer back at the mixer.

Sound engineers often travel with quite a bit of special equipment, all loaded into a giant travel-ready durable box called a rack. In a rack, you might find preamps, equalizers, crossovers, effects units, compressors, and more. The use of this equipment often holds the engineer’s secrets for great sound and even provides the “signature” sound some artists are known for.

Prior to a live evening concert, sound checks are held to prepare for the big night. Sound checks serve multiple purposes — to balance the sound of onstage instruments and singers, to eliminate potential feedback problems, and to ensure that the mix sounds right within the particular acoustic space. Also, if a component is missing or is not working, there’s time to run to the local music store to pick up a replacement part.

In a recording studio, the booth is a small soundproof room in which singers and instrumentalists record. It is separate from where the engineer/producer works with the mixing equipment to do the recording. Studios are designed to control sound in order to obtain the best-quality recording possible. As a result, the concrete or brick walls are usually built extra thick, join at odd angles, and are covered with sound baffling/padding. Doors are doubled and often have a pocket of air in between so that soundwaves don’t enter or exit the studio.

 

Student Worksheet

1.  List or draw the signal chain of six basic events in
 sound systems.

2.  What is the primary job of a microphone?

3.  Name five different kinds of mics.

4.  What is the purpose of the wire mesh and foam
 windscreen on a microphone?

5.  What are the Shure SM57 and SM58 renowned for?

6.  What is the primary purpose of a mixing board?

7.  Who is in charge of the mixer and makes a live band
 sound great?

8.  What do some of the knobs on the mixer control?
 (Name three functions.)

9.  What’s another name for the sliders on a mixer, and
 what do they do?

10.   What is the primary purpose of an amplifier?

11.   How are amps rated?

12.   List the approximate amount of wattage needed to
 power the following:

                    a. Car stereo

                    b. Powerful home stereo

                    c. Small concert club

                    d. Large arena/outdoor venue

13.   What is a speaker’s primary job?

14.   What is a monitor?

15.   What is Mr. Laakso’s Law of Inverse Proportions for
 Performer Sound System Requests?

16.   What is the purpose of a sound check?

17.   What is feedback?

18.   What is the name of the large, durable box that holds
 other “special effects” equipment the sound engineer
 uses (such as compressors, preamps, effects units,
 EQs, and so on)?

19.   In a recording studio, what is the name of the small,
 soundproof room in which the singers and
 instrumentalists record? (It is separate from where
 the engineer/producer works.)

20.   Name two ways the design of a recording studio
 helps to control sound for excellent recording.

 

Answers/Study Guide

Q: List or draw the signal chain of six basic events in sound
 systems. 
  

A: Singer/instrument – microphone – mixer – amplifier –
 speaker – ear

 

Q: What is the primary job of a microphone?
           

A: It converts audio signals into electrical signals.

 

Q: Name five different kinds of mics. 
         

A: Handheld, lavalier, boom, headset, wireless

 

Q: What is the purpose of the wire mesh and foam
 windscreen on a microphone?
          

A: They protect the mic from saliva, rough contact, and
 strong air gusts.

 

Q: What are the Shure SM57 and SM58 renowned for? 


A: They’re used in live concerts around the world, and
 they’re built like tanks.

 

Q: What is the primary purpose of a mixing board? 
  

A: It combines all mic/line inputs into one output and
 controls the sound.

 

Q: Who is in charge of the mixer and makes a live band
 sound great? 


A: The front-of-house sound engineer

 

Q: What do some of the knobs on the mixer control?
 (Name three functions.) 


A: Treble/bass, special effects, speakers for the band
 (monitors), mic sensitivity, pan (left/right)

 

Q: What’s another name for the sliders on a mixer, and what
 do they do?

A: Faders — they control volumes of the mics and
 instruments.

 

Q: What is the primary purpose of an amplifier? 


A: To boost the electrical signal on its way to the speaker

 

Q: How are amps rated?


A: According to watts — the more watts, the louder they are

 

Q: List the approximate amount of wattage needed to
 power the following: 


     a. Car stereo: 40–100
  

     b. Powerful home stereo: 100–500 


     c. Small concert club: 500–5,000


     d. Large arena/outdoor venue: 10,000 or more

 

Q: What is a speaker’s primary job? 


A: It converts electrical signals to audio signals
 (the opposite of a mic).

 

Q: What is a monitor? 


A: A wedge-shaped onstage speaker that lets performers
 hear themselves play or sing.

 

Q: What is Mr. Laakso’s Law of Inverse Proportions for
 Performer Sound System Requests?


A: The more experienced/talented a performer is, the less
 he or she will fuss over the sound system—the performer
 will sound great no matter what.

 

Q: What is the purpose of a sound check? 


A: To balance the sound of the band, eliminate feedback,
 and detect problems

 

Q: What is feedback? 


A: When sound gets trapped in a loop and amplified into a
 terrible noise

    

Q: What is the name of the large, durable box that holds
 other “special effects” equipment the sound engineer uses
 (such as compressors, preamps, effects units, EQs, and so
 on)? 


A: The rack

 

Q: In a recording studio, what is the name of the small
 soundproof room in which the singers and instrumentalists
 record? (It is separate from where the engineer/producer
 works.)


A: The booth

 

Q: Name two ways the design of a recording studio helps to
 control sound for excellent recording.


A: Walls are not parallel, sound baffling/padding is used
  everywhere, walls are extra thick and often made of concrete
 or brick, doors are doubled and often have a pocket of air in
 between. Sound should not leak in or out.

 

Project

In this project you will play the role of musician/composer as well as sound engineer. You will write a song, record the song, and engineer the mix in a highly simplified way using an online program called JamStudio.

Go to www.jamstudio.com. Create a login and password so you can save and share your work. In a classroom setting, one login can be created for the whole class, songs can bear the names of their student creators, and all work can be saved in a central location.

You will create a simple blues song with a middle section in A-B-A form. Chords in a blues song always follow this order (your A section):

G-G-G-G

C-C-G-G

D-C-G-G

The middle section, which you will compose on Page 2, needs totally different instruments and style. Use the chords from the following (your B section):

Em-C-Em-C or Em-C-Am-D or G-F-C-D     

You don’t have to keep the song in the key of G, as listed above. You can change keys.

Your song needs to play in the order of A-B-A, so in the Play Page Order box, type 1,2,1. This will guarantee your song sounds great!

Experiment and choose any instruments or styles you’d like. Mix the instruments with care—listen to what you’d like to be louder or softer. Be original!

When you are finished, click on Save and title the song your full name, such as John Smith.

You may create extra songs for extra credit in the same A-B-A format.

Grading

25 points

Following the correct blues chords listed above

25 points

Having the correct order of the song in A-B-A

25 points

Taking care to choose a nice instrumentation with a different B section

25 points

Demonstrating originality and creativity

100 points

 Totally awesome!

 

Brian BookBrian Laakso is a classically trained (and punk-rock inspired) pianist who attended Oberlin Conservatory of Music and Kent State University, where he learned about the philosophy, power, and purpose of teaching. Since then, he has taught middle school at a private boys’ academy, rocked groups of K–6 students from a rolling cart, and currently teaches music technology, songwriting, and multimedia at McKinley High School in Canton, Ohio. Brian advises music teachers nationwide as secretary of the Technology Institute for Music Educators (ti-me.org).

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