Chapter 5 Waves I: Generalities, Superposition & Standing Waves
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Rotational and Translational Waves in a Bowed String Eric Bavu, Manfred Yew, Pierre-Yves Pla•Ais, John Smith and Joe Wolfe
Proceedings of the International Symposium on Musical Acoustics, March 31st to April 3rd 2004 (ISMA2004), Nara, Japan Rotational and translational waves in a bowed string Eric Bavu, Manfred Yew, Pierre-Yves Pla•ais, John Smith and Joe Wolfe School of Physics, University of New South Wales, Sydney Australia [email protected] relative motion of the bow and string, and therefore the Abstract times of commencement of stick and slip phases, We measure and compare the rotational and transverse depends on both the transverse and torsional velocity velocity of a bowed string. When bowed by an (Fig 2). Consequently, torsional waves can introduce experienced player, the torsional motion is phase-locked aperiodicity or jitter to the motion of the string. Human to the transverse waves, producing highly periodic hearing is very sensitive to jitter [9]. Small amounts of motion. The spectrum of the torsional motion includes jitter contribute to a sound's being identified as 'natural' the fundamental and harmonics of the transverse wave, rather than 'mechanical'. Large amounts of jitter, on the with strong formants at the natural frequencies of the other hand, sound unmusical. Here we measure and torsional standing waves in the whole string. Volunteers compare translational and torsional velocities of a with no experience on bowed string instruments, bowed bass string and examine the periodicity of the however, often produced non-periodic motion. We standing waves. present sound files of both the transverse and torsional velocity signals of well-bowed strings. The torsional y string signal has not only the pitch of the transverse signal, but kink it sounds recognisably like a bowed string, probably because of its rich harmonic structure and the transients and amplitude envelope produced by bowing. -
The Science of String Instruments
The Science of String Instruments Thomas D. Rossing Editor The Science of String Instruments Editor Thomas D. Rossing Stanford University Center for Computer Research in Music and Acoustics (CCRMA) Stanford, CA 94302-8180, USA [email protected] ISBN 978-1-4419-7109-8 e-ISBN 978-1-4419-7110-4 DOI 10.1007/978-1-4419-7110-4 Springer New York Dordrecht Heidelberg London # Springer Science+Business Media, LLC 2010 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper Springer is part of Springer ScienceþBusiness Media (www.springer.com) Contents 1 Introduction............................................................... 1 Thomas D. Rossing 2 Plucked Strings ........................................................... 11 Thomas D. Rossing 3 Guitars and Lutes ........................................................ 19 Thomas D. Rossing and Graham Caldersmith 4 Portuguese Guitar ........................................................ 47 Octavio Inacio 5 Banjo ...................................................................... 59 James Rae 6 Mandolin Family Instruments........................................... 77 David J. Cohen and Thomas D. Rossing 7 Psalteries and Zithers .................................................... 99 Andres Peekna and Thomas D. -
Standing Waves and Sound
Standing Waves and Sound Waves are vibrations (jiggles) that move through a material Frequency: how often a piece of material in the wave moves back and forth. Waves can be longitudinal (back-and- forth motion) or transverse (up-and- down motion). When a wave is caught in between walls, it will bounce back and forth to create a standing wave, but only if its frequency is just right! Sound is a longitudinal wave that moves through air and other materials. In a sound wave the molecules jiggle back and forth, getting closer together and further apart. Work with a partner! Take turns being the “wall” (hold end steady) and the slinky mover. Making Waves with a Slinky 1. Each of you should hold one end of the slinky. Stand far enough apart that the slinky is stretched. 2. Try making a transverse wave pulse by having one partner move a slinky end up and down while the other holds their end fixed. What happens to the wave pulse when it reaches the fixed end of the slinky? Does it return upside down or the same way up? Try moving the end up and down faster: Does the wave pulse get narrower or wider? Does the wave pulse reach the other partner noticeably faster? 3. Without moving further apart, pull the slinky tighter, so it is more stretched (scrunch up some of the slinky in your hand). Make a transverse wave pulse again. Does the wave pulse reach the end faster or slower if the slinky is more stretched? 4. Try making a longitudinal wave pulse by folding some of the slinky into your hand and then letting go. -
7.7.4.2 Damping of Longitudinal Waves Chapter 7.7.4.1 Had Shown That a Coupling of Transversal String-Vibrations Occurs at the Bridge and at the Nut (Or Fret)
7.7 Absorption of string oscillations 7-75 7.7.4.2 Damping of longitudinal waves Chapter 7.7.4.1 had shown that a coupling of transversal string-vibrations occurs at the bridge and at the nut (or fret). In addition, transversal and longitudinal oscillations exchange part of their oscillation energy, as well (Chapters 1.4 and 7.5.2). The dilatational waves induced that way showed high loss factors in the decay measurements: individual partials decay rapidly, i.e. they exhibit short decay times. For the following vibration measurements, a Fender US- Standard Stratocaster was used with its tremolo (aka vibrato) genre-typically adjusted to be floating. The investigated string was plucked fretboard-normally close to the nut; an oscillation analysis was made close to the bridge using a laser vibrometer. Fig. 7.70: Decay (left) and time function of the fretboard-normal velocity. Dilatational wave period = 0.42 ms. For the fretboard normal velocity, the left-hand image in Fig. 7.70 shows the decay time of the D3-partials. Damping maxima – i.e. T30 minima – can be identified at 2.36, at 4.7 and at 7.1 kHz; resonances of dilatational waves can be assumed to be the cause. In the time function we can see that - even before the transversal wave arrives at the measurement point – small impulses with a periodicity of 0.42 ms occur. Although the laser vibrometer (which is sensitive to lateral string oscillations) cannot itself detect the dilatational waves, it does capture their secondary waves (Chapter 1.4). Apparently, dilatational waves are absorbed efficiently in the wound D-string, and a selective damping arises at a frequency of 2.36 kHz (and its multiples). -
Giant Slinky: Quantitative Exhibit Activity
Name: _________________________________________________________________ Giant Slinky: Quantitative Exhibit Activity Materials: Tape Measure, Stopwatch, & Calculator. In this activity, we will explore wave properties using the Giant Slinky. Let’s start by describing the two types of waves: transverse and longitudinal. Transverse and Longitudinal Waves A transverse wave moves side-to-side orthogonal (at a right angle; perpendicular) to the direction the wave is moving. These waves can be created on the Slinky by shaking the end of it left and right. A longitudinal wave is a pressure wave alternating between high and low pressure. These waves can be created on the Slinky by gathering a few (about 5 or so) Slinky rings, compressing them with your hands and letting go. The area of high pressure is where the Slinky rings are bunched up and the area of low pressure is where the Slinky rings are spread apart. Transverse Waves Before we can do any math with our Slinky, we need to know a little more about its properties. Begin by measuring the length (L) of the Slinky (attachment disk to attachment disk). If your tape measure only measures in feet and inches, convert feet into meters using 1 ft = 0.3048 m. Length of Slinky: L = __________________m We must also know how long it takes a wave to travel the length of the Slinky so that we can calculate the speed of a wave. For now, we are going to investigate transverse waves, so make a single pulse by jerking the Slinky sharply to the left and right ONCE (very quickly) and then return the Slinky to the original center position. -
Woods for Wooden Musical Instruments S
ISMA 2014, Le Mans, France Woods for Wooden Musical Instruments S. Yoshikawaa and C. Walthamb aKyushu University, Graduate School of Design, 4-9-1 Shiobaru, Minami-ku, 815-8540 Fukuoka, Japan bUniversity of British Columbia, Dept of Physics & Astronomy, 6224 Agricultural Road, Vancouver, BC, Canada V6T 1Z1 [email protected] 281 ISMA 2014, Le Mans, France In spite of recent advances in materials science, wood remains the preferred construction material for musical instruments worldwide. Some distinguishing features of woods (light weight, intermediate quality factor, etc.) are easily noticed if we compare material properties between woods, a plastic (acrylic), and a metal (aluminum). Woods common in musical instruments (strings, woodwinds, and percussions) are typically (with notable exceptions) softwoods (e.g. Sitka spruce) as tone woods for soundboards, hardwoods (e.g. amboyna) as frame woods for backboards, and monocots (e.g. bamboo) as bore woods for woodwind bodies. Moreover, if we consider the radiation characteristics of tap tones from sample plates of Sitka spruce, maple, and aluminum, a large difference is observed above around 2 kHz that is attributed to the relative strength of shear and bending deformations in flexural vibrations. This shear effect causes an appreciable increase in the loss factor at higher frequencies. The stronger shear effect in Sitka spruce than in maple and aluminum seems to be relevant to soundboards because its low-pass filter effect with a cutoff frequency of about 2 kHz tends to lend the radiated sound a desired softness. A classification diagram of traditional woods based on an anti-vibration parameter (density ρ/sound speed c) and transmission parameter cQ is proposed. -
University of California Santa Cruz the Vietnamese Đàn
UNIVERSITY OF CALIFORNIA SANTA CRUZ THE VIETNAMESE ĐÀN BẦU: A CULTURAL HISTORY OF AN INSTRUMENT IN DIASPORA A dissertation submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in MUSIC by LISA BEEBE June 2017 The dissertation of Lisa Beebe is approved: _________________________________________________ Professor Tanya Merchant, Chair _________________________________________________ Professor Dard Neuman _________________________________________________ Jason Gibbs, PhD _____________________________________________________ Tyrus Miller Vice Provost and Dean of Graduate Studies Table of Contents List of Figures .............................................................................................................................................. v Chapter One. Introduction ..................................................................................................................... 1 Geography: Vietnam ............................................................................................................................. 6 Historical and Political Context .................................................................................................... 10 Literature Review .............................................................................................................................. 17 Vietnamese Scholarship .............................................................................................................. 17 English Language Literature on Vietnamese Music -
Experiment 12
Experiment 12 Velocity and Propagation of Waves 12.1 Objective To use the phenomenon of resonance to determine the velocity of the propagation of waves in taut strings and wires. 12.2 Discussion Any medium under tension or stress has the following property: disturbances, motions of the matter of which the medium consists, are propagated through the medium. When the disturbances are periodic, they are called waves, and when the disturbances are simple harmonic, the waves are sinusoidal and are characterized by a common wavelength and frequency. The velocity of propagation of a disturbance, whether or not it is periodic, depends generally upon the tension or stress in the medium and on the density of the medium. The greater the stress: the greater the velocity; and the greater the density: the smaller the velocity. In the case of a taut string or wire, the velocity v depends upon the tension T in the string or wire and the mass per unit length µ of the string or wire. Theory predicts that the relation should be T v2 = (12.1) µ Most disturbances travel so rapidly that a direct determination of their velocity is not possible. However, when the disturbance is simple harmonic, the sinusoidal character of the waves provides a simple method by which the velocity of the waves can be indirectly determined. This determination involves the frequency f and wavelength λ of the wave. Here f is the frequency of the simple harmonic motion of the medium and λ is from any point of the wave to the next point of the same phase. -
1S-13 Slinky on Stand
Sound light waves... waves... water waves... 1S-13 Slinky on Stand Creating longitudinal compression waves in a slinky What happens when you pull back and release one end of the slinky ? Physics 214 Fall 2010 11/18/2019 3 Moving one end of the Slinky back and forth created a local compression where the rings of the spring are closer together than in the rest of the Slinky. The slinky tries to return to equilibrium. But inertia cause the links to pass beyond. This create a compression. Then the links comes back to the equilibrium point due to the restoration force, i.e. the elastic force. The speed of the pulse may depend on factors such as tension in the Slinky and the mass of the Slinky. Energy is transferred through the Slinky as the pulse travels. The work done in moving one end of the Slinky increases both the potential energy of the spring and the kinetic energy of individual loops. This region of higher energy then moves along the Slinky and reaches the opposite end. There, the energy could be used to ring a bell or perform other types of work. Energy carried by water waves does substantial work over time in eroding and shaping a shoreline. If instead of moving your hand back and forth just once, you continue to produce pulses, you will send a series of longitudinal pulses down the Slinky. If equal time intervals separate the pulses, you produce a periodic wave. The time between pulses is the period T of the wave. The number of pulses or cycles per unit of time is the frequency f = 1/T. -
Class Summer Vacation, 2021-22 Subject
HOLIDAY HOMEWORK: Class 10 IG Summer Vacation, 2021-22 Subject : English Literature Time to be Spent One hour for fifteen days (Hours per day for ___ Days) : Work Read the text of Shakespeare’s Othello. Specification : Materials Hard copy or soft copy of the text of the drama Othello Required : Read the original text and the paraphrase. Make a presentation in about 15 slides . Some online resources are shared below: https://www.youtube.com/watch?v=2aRr6-XXAD8 Instructions / https://www.youtube.com/watch?v=95Vfcb7VvCA Guidelines : https://www.youtube.com/watch?v=Bp6LqSgukOU https://www.youtube.com/watch?v=lN4Kpj1PFKM https://www.youtube.com/watch?v=5z19M1A8MtY Any other Information: 1. List of the characters. 2. Theme of the drama 3. Act wise summary Date of Submission: 30th June 2021 ( you have to present your research in classroom) Head of the Department HOLIDAY HOMEWORK: Class 10 IG Summer Vacation, 2021-22 Subject : BUSINESS STUDIES (0450) Time to be Spent 6 Hours (1 ½ Hours per day for 4 Days) : Past papers for both components. Work Specification : Materials BUSINESS STUDIES (0450) TEXT BOOK Required : Students are expected to take printout of papers using the link: https://drive.google.com/file/d/1RJO1dBuq2eceLwKZ3ptolKL5JZP76rKW/view?usp=sharing Student should strictly avoid copying the answers from the books/ marking Instructions / scheme for their own benefit and well- being. Guidelines: Students are expected to take a print of all the papers given, get them spiral-bind and solve them in the space provided in the question paper itself and avoid taking extra sheet. Any other Information: Answers must fulfill all the criteria of assessment objectives. -
Harmonic Waves the Golden Rule for Waves Example: Wave on a String
Harmonic waves L 23 – Vibrations and Waves [3] each segment of the string undergoes ¾ resonance √ simple harmonic motion ¾ clocks – pendulum √ ¾ springs √ a snapshot of the string at some time ¾ harmonic motion √ ¾ mechanical waves √ ¾ sound waves ¾ golden rule for waves ¾ musical instruments ¾ The Doppler effect z Doppler radar λ λ z radar guns distance between successive peaks is called the WAVELENGTH λ it is measured in meters The golden rule for waves Example: wave on a string • This is the relationship between the speed of the wave, the wavelength and the period or frequency ( T = 1 / f ) • it follows from speed = distance / time 2 cm 2 cm 2 cm • the wave travels one wavelength in one • A wave moves on a string at a speed of 4 cm/s period, so wave speed v = λ / T, but • A snapshot of the motion reveals that the since f = 1 / T, we have wavelength(λ) is 2 cm, what is the frequency (ƒ)? • v = λ f •v = λ׃, so ƒ = v ÷ λ = (4 cm/s ) / (2 cm) = 2 Hz • this is the “Golden Rule” for waves Why do I sound funny when Sound and Music I breath helium? • SoundÆ pressure waves in a solid, liquid • Sound travels twice as fast in helium, or gas because Helium is lighter than air • Remember the golden rule v = λ׃ • The speed of soundÆ vs s • Air at 20 C: 343 m/s = 767 mph ≈ 1/5 mile/sec • The wavelength of the sound waves you • Water at 20 C: 1500 m/s make with your voice is fixed by the size of • copper: 5000 m/s your mouth and throat cavity. -
Standing Waves Physics Lab I
Standing Waves Physics Lab I Objective In this series of experiments, the resonance conditions for standing waves on a string will be tested experimentally. Equipment List PASCO SF-9324 Variable Frequency Mechanical Wave Driver, PASCO PI-9587B Digital Frequency Generator, Table Rod, Elastic String, Table Clamp with Pulley, Set of 50 g and 100 g Masses with Mass Holder, Meter Stick. Theoretical Background Consider an elastic string. One end of the string is tied to a rod. The other end is under tension by a hanging mass and pulley arrangement. The string is held taut by the applied force of the hanging mass. Suppose the string is plucked at or near the taut end. The string begins to vibrate. As the string vibrates, a wave travels along the string toward the ¯xed end. Upon arriving at the ¯xed end, the wave is reflected back toward the taut end of the string with the same amount of energy given by the pluck, ideally. Suppose you were to repeatedly pluck the string. The time between each pluck is 1 second and you stop plucking after 10 seconds. The frequency of your pluck is then de¯ned as 1 pluck per every second. Frequency is a measure of the number of repeating cycles or oscillations completed within a de¯nite time frame. Frequency has units of Hertz abbreviated Hz. As you continue to pluck the string you notice that the set of waves travelling back and forth between the taut and ¯xed ends of the string constructively and destructively interact with each other as they propagate along the string.