After this activity, students should be able to:

• Explain how surfaces reflect sound waves.
• Develop blueprints for a structure to be constructed.
• Explain why certain materials absorb more sound than others.
• Write a formal lab report.

Sound booths and sound dampening materials are used in the recording industry to produce high-quality recordings of music that people listen to on iPods (MP3s), CDs, the radio, movies and through the internet. Without high-performance sound dampening materials, music tracks would be mixed with environmental background noises from outside recording studios. And recording studios and practice studios would not be as readily available if sound dampening materials did not perform well. Imagine if your band rented a practice space in a building with other practice spaces and no sound proofing; you would constantly be hearing everyone else playing. The only time you would ever get a chance to practice and only hear your band's music would be when all other bands were not in the studio!

What are some situations, spaces and products in which sound dampening and sound reflecting materials would be useful? click for copyright

In our sometimes noisy world, we have a definite need for sound proofing and sound dampening capabilities — for musical purposes, as well as many other activities such as conference room meetings and library studying. Engineers design and create sound dampening structures that are used in recording studios, concert halls, movie theaters and even hospitals. What are some other spaces where you think sound dampening would be useful?

Background

Stand-alone sound booths or sound isolation booths are built with fairly thick walls of about 3.75-inches (9.5 cm). The interior booth walls are covered with polyurethane acoustic foam or some other sound dampening type of material. The exterior of the booth is covered with an acoustic fabric to dampen the sound. Various other types of materials, such as baffles, ceiling tiles, vinyl barriers and some rubber products are used to dampen the sound in the booths. In situations in which a sound booth is not used, regular rooms can be made more sound proof by adding products to the walls, ceilings and floors to help eliminate outside noises from entering. In some instances, studio floors are even elevated to detach them from the overall building structures, eliminating more vibrations from entering the recording spaces.

Before the Activity

• Gather materials and make copies of the Building a Sound Booth Worksheet, one per group.
• Divide the various supplies into groups.
• Divide the class into teams of three or four students each.

With the Students

1. Ask students which materials would be best for sound dampening and why.
2. Explain to the students that their job is to act as engineers and design and build model sound booths that can dampen the sound generated inside as much as possible, given the materials provided.
3. Hand out the worksheets and have each group complete the Brainstorming section. Make available a sample of each supply material for students to see and touch.
4. Have teams create Blueprint Designs of their sound booths, preparing a detailed list of materials needed on their worksheets.
5. Approve the blueprint design plan from each group only if all supplies are listed with exact amounts and the design is realistic.
6. Once all groups have approved blueprints, demonstrate the correct procedure for cutting the poster board to form the shell of the sound booth, as described on the worksheet.
7. Direct students to trace the outline of the shell on their poster boards.
8. Check each group's traced outline before allowing them to cut the poster board.
9. Distribute only the materials each group needs to construct its sound booth from its blueprint.
10. Have the teams construct their sound booths with their requested materials only.
11. To simulate a real-world situation, limit how much time students are given to construct their model sound booths.
12. After students have completed their sound booths, it is time to test each group's prototype.
13. To test a sound booth, place the booth over the audio speaker, like an upside down cup. Place a decibel meter next to the booth.

    Activity testing set-up. click for copyright

14. To make the testing accurate between prototypes, play the same audio clip at the same volume level for each booth test.
15. For each sound booth test, have students record the highest decibel level reached in the table in the Data Collection section on the worksheet.
16. After testing, have each group go to the front of the room and explain the construction of its sound booth and why it was made in that manner.
17. Have students complete the Analysis and Conclusions sections of their worksheets.
18. Lead a class discussion about why certain sound booths performed better than others and why certain materials work better than others.
19. Assign students to write formal lab reports as described in the Assessment section.

• Alert the students to be careful cutting poster board with scissors.

• What materials, besides the ones used, might better dampen the sound?
• Which types of materials are better to use: sound reflecting, sound absorbing materials or both?

As a homework assignment or during free time, have students experiment with the sound dampening ability of other materials.

Have students create a new sound booth with an unrestricted supply list and test its sound dampening ability.

Learn more about the world-class sound recording and production services at the Fantasy Studios at Zaentz Media Center in Berkeley, CA. Click on their Gallery link to see photographs of their sound recording studios and control booths. See: http://www.fantasystudios.com/studios.html