Intro
This paper will explain how sound works, how it is transmitted, and how it is produced from three different types of instruments. Sound is a wave that is known as a longitudinal wave. These waves consist of expansions and rarefaction. The different pitches of the sounds you hear is the different frequencies. The higher the frequency, the closer together the sound compression. This makes a higher pitched noise. The lower the frequency, the farther apart the sound compression. This produces a lower pitched noise. Sound is produced from vibrations. In wind instruments, the vibrations come from the player blowing into a reed which vibrates and makes noise. In a string instrument, the vibrations come from the player plucking the strings and making them vibrate back and forth. The frequencies in string instrument are dependent on the tension in the string. The tighter the string, the faster it vibrates back and forth, which produces a higher frequency.
Wind Insrument
For our wind instrument, we built a PVC imitation of a clarinet. It was made by cutting a piece of ¾ PVC pipe to the proper length for our notes, drilling holes in the side in a rough line on one side, and bore the ¾ in interior diameter of the pipe on one side to a diameter of ⅞ in. We also brought a clarinet mouthpiece to start the vibration of our instrument using its reed. Our group calculated the location of the holes by calculating ¼ of the wavelength for each note. Then we had to adjust the location of the holes on our current version to more accurately match notes due to human error and the PVC pipe’s natural frequency. Each hole for each wavelength is ¼ the wavelength due way this wind instrument making sound by creating a high pressure area in the instrument which is move to the normal pressure of the air. This makes it ¼ the wavelength and the different notes caused by the air being relieved to normal pressure at shorter and longer points
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Strings
In this project we built an upright bass for our string instrument. We built it out of plywood and 2x4’s. The strings were heavy duty fishing line. The way that you change note is by putting your finger on the strings, decreasing the length of the string and increasing the frequency. Plucking the string will cause the string to vibrate back and forth, disrupting the air around the string, allows for longitudinal waves to be produced, also known as sound waves. The note produced will depend on the length and tension of the string. The length is equal to half of the wavelength. This is because one pluck will cause the vibrate back and forth at half of a wavelength, which is all that is needed to produce a wave.
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Percussion
We chose to build a xylophone for our percussion instrument in this project. We built a series of PVC tubes at different lengths that produced different notes. Different notes were produced from the length of the tubes because each tube is the exactly ¼ the length of the wavelength. We made each tube ¼ of the wavelength because the wavelength is at it’s highest displacement at this point. Our percussion instrument works similarly to a wind instruments by making a high pressure zone and moving the air to a low pressure zone. Allowing a noise to be made. Our percussion instrument has a scale of E5 to G3.
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Drums
Our drum set is made of a plywood table and plastic buckets. One of the plastic buckets is covered in duct tape which vibrates less because it has less natural frequency than the bucket itself. One of our drums is just the bucket. Our next drum is a bucket with a aluminum sheet over it. We were hoping to replicate a snare drum with sheet metal and a half circle of cardboard to absorb the metal sounding noise. Our last drum is a bass drum. It makes a deeper noise because it has a fatter surface and the duct tape has a very low natural frequency and that makes it have a bass sound. The next part of our drum is our cymbal. The thing that makes it sound like a cymbal is the natural frequency of the metal. The metal has a high natural frequency which means it vibrates more than the duct tape. The last part of our drum is the table which is available at IKEA.
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Tables
You can find our tables with all the lengths of our instruments in this document.
Reflection
During this project I learned many things about building/engineering design and also about music and the many different sound and light waves that make sound and light. Two positives I found from this experience is learning how to amplify sound and learning about how to become a better worker, teammate, and leader. It was a real struggle learning how to amplify the sound especially from the stand up base. It took a long time but we eventually overcame the challenge by making an amphitheater set up which projects the sound. I learned to be a better teammate during this project because on many days some group members were absent so I played many roles. On some days I was the leader, handing out jobs while working and on some days I took orders and helped where help was needed.
One negative thing that I can learn from was that the measurements of each hole and tube need to be correct. If these are not put in the right place then the notes won't be correct. Another thing I can learn from is to always do the harder things first because we didn't and found ourselves rushed with difficult concepts and challenges in the final days. All in all this was a great project that I learned a lot from and hopefully will be able to do again sometime.
One negative thing that I can learn from was that the measurements of each hole and tube need to be correct. If these are not put in the right place then the notes won't be correct. Another thing I can learn from is to always do the harder things first because we didn't and found ourselves rushed with difficult concepts and challenges in the final days. All in all this was a great project that I learned a lot from and hopefully will be able to do again sometime.