lecture19 - String Instruments 1 General comments Vibration...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
String Instruments 1. General comments Vibration of strings - standing waves Fundamental: Harmonics: The fundamental frequency and harmonics are determent by length, L , tension, F, and linear mass density, μ. Usually, length and mass of the string remain constant, and turning is accomplished by changing tension. Timbre is mainly determined by harmonics The combination of harmonics depends on the method of string excitation (plucked, bowed or struck by a hammer; exited in the center or at the edge), and on the resonances (ear and wood resonances) ( 29 L v v f L 2 ; 2 / 1 1 = = = λ λ 1 1 ; / nf f n n n = = λ λ μ F v =
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2. Vibration of a plucked string http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html Some properties: String plucked at its center contains only odd harmonics. Intensity of these harmonics decays as 1/n 2 , where n is the harmonic’s number If distance from the end is 1/n (n=1,2,3…) then n-th harmonic is missing Harmonic Ampliude Phase 1 1 + 2 0 none 3 1/9 - 4 0 none 5 1/25 + 6 0 none 7 1/49 - Plucked at its center Harmonic Ampliude Phase 1 1 + 2 0.40 + 3 0.18 + 4 0.06 + 5 0 none 6 0.03 - Plucked at 1/5 of length
Image of page 2
3. Vibration of a bowed string Displacement and velocity During the grater part of each period, the string is carried along by bow. Then it suddenly detaches itself and moves rapidly beck until it is caught by the moving bow again. Frequency is determent by length, L , tension, F, and linear mass density, μ. The beginning and the end of slippage depend on position of the bow. For each position there is maximum and minimum bowing force. Closer to the bridge these forces are stronger.
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4. Violin Violin Construction: four strings (of steel or gut) tuned to G 3 , D 4 , A 4 , E 5 (196.0, 293.7, 440.0, 659.3 Hz) What is the interval?
Image of page 4
Vibration of the violin body. Important factor in sound quality To determine normal modes forces can be applied to the bridge Most of the sound that a listener hears from a violin is radiated into the air from the top and back plates The sound quality can be changed considerably by the place where the string is bowed:
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern