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Plugged-In. Michelle Pfahles Grade 10 Mrs. Harlan New Castle Sr. High School. Observation.
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Plugged-In Michelle Pfahles Grade 10 Mrs. Harlan New Castle Sr. High School
Observation Everyday, I listen to music on my iPod. I’m always “plugged-in.” One day, I forgot my earphones, so I ran into the store to buy new ones. I got the cheapest pair of earphones that they had. When I plugged the new earphones into my iPod, I realized that it sounded much different than when I used my other earphones. This lead my to wonder if certain brands of earphones affected the quality of the music we hear. I wondered if certain earphones would produce better sound quality in high range, low range, and middle range.
Research • frequency- number of complete cycles per second • Hertz (Hz)- unit of frequency in a cycle of a sound wave • 20 Hz is the lower limit of human hearing • 22000 Hz is the upper limit of human hearing • oscilloscope- instrument used to analyze and display waveform • waveform- represents the alternating current changes with time (sine, square, ramp, saw tooth, and triangular) • Audacity is a program used to produce or record Hz or any other audio
Sources • "Audacity: About Audacity." Audacity: Free Audio Editor and Recorder. N.p., n.d. Web. 25 Nov. 2013. audactiy.sourceforge.net/about • "The Ultimate Headphones Test." Audio Tests, Test Tones and Tone Generators - Online and Free. N.p., n.d. Web. 25 Nov. 2013. www.audiocheck.net/soundtests_headphones.php
Variables • Independent Variable- Type of Earphones • Dependent Variable- Sound Quality • Controls- • Distance of earphones from microphone • How long each note is played • Audacity program • Quiet room where the test takes place
Materials • different types of earphones (Apple, iHip, off-brand earphones, … ect.) • audacity program • microphone • two computers
Procedure • Obtain 4 different types of earphones • iHeadphones 4 • iHeadphones 5 • iHip • Offbrand earphones • Download audacity onto both computers • Find a quiet and enclosed room with a table • Open audacity on both computers • Create a file on audacity. Play each sound for a total of five sections, and leave one second of rest time in between each sound • 100 Hz • 200 Hz • 400 Hz • 800 Hz • 1600 Hz • 3200 Hz • 6400 Hz • 12800 Hz • 22000 Hz • Plug microphone into the computer with the file and place other side into the hole drilled in the Styrofoam • Plug earphones into the other computer and place an earbud into the opposite hole in the Styrofoam
Procedure cont. • Record the file produced on the computer with the microphone • Save each sound clip with the number of Hz and the earphone brand • Change the earphones • Repeat steps 8-9 for each set of earphones • Analyze and rate the quality for each earphone • 1st = Best Quality= 4 points • 2nd = Good Quality= 3 points • 3rd = Okay Quality= 2 points • 4th = Worst Quality = 1 point
Analyze 100 Hz