DOCSLIB.ORG

Musical String Inharmonicity

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Musical String Inharmonicity Musical String Inharmonicity Chris Murray Dr. Scott Whitfield, Department of Physics Introduction In general, we perceive simultaneous discrete frequencies to be more pleasing if the frequen- cies have simple ratio relationships with each other. In fact, in the classical western theory of music, the perfect fifth is the most consonant pitch pair, and in the ideal case the frequency Where u is mass per unit length, T is the string ratio between the fundamentals of the pitches tension, S is the cross-sectional area, K is half would be three to two. By contrast, a dissonant of the radius of the string and E is Young’s mod- pitch pair, the minor second, has a frequency ulus. Young’s modulus for a string is a measure ratio between the fundamentals of about sixteen of its resistance to changes in length. In other to fifteen. words, it is a measure of the string’s stiffness, so it can be said that it is the parameter that is This study examines an effect called inharmo- the first cause for inharmonicity. Equation (1) nicity as it applies to a single plucked musical differs from the wave equation for an ideal string string. When a musical string vibrates, it carries only by the addition of the term that involves many discrete frequencies called harmonics. In the fourth derivative of the displacement of the the ideal case, these harmonics would vibrate string from its equilibrium position. So, if the with frequencies that are perfect integer multi- string had no stiffness, E would equal zero, ples of the fundamental, the lowest frequency there would be no extra term in this modified being carried by the string. Inharmonicity, in the wave equation, and there would be no inharmo- case that this study addresses, is the behavior nicity in the string. where harmonics are pulled higher than their ideal values, and the effect becomes more pro- The solutions to equation (1) carry the same as- nounced as the order of the harmonic increases. sumptions as do the solutions for the ideal wave A very inharmonic string may even sound out equation: The string has uniform linear density, of tune with itself, which might give the string a it is under constant tension, and the displace- harsh sound with undesirable resonances. ment of the string is small enough that tension for any infinitesimal segment does not vary as The model that is tested in this study was it vibrates. The solutions also assume that the brought into the active literature by NH Fletcher ends of the vibrating section of the strings are in the 1960’s.1 It places the cause of inharmonic- supported, such as a guitar string at the bridge ity solely on the stiffness of the string material. or the nut, or a piano string. This assumption The equation from which this model is created leads to the mathematical statements that at the is: ends of the string: 17 ASTRA - The McNair Scholars’ Journal That is the string is stationary on the support, creasing the string’s stiffness or diameter. Clear- and: ly, a builder of plucked or hammered stringed musical instruments will be forced to balance the different factors that affect inharmonicity. It is not an effect that can be fully eliminated in any prac- tical way. The consequence of this mathematical state- ment is that the influence of the stiffness of the So, musical string inharmonicity is not merely an string material does not travel over the support. academic curiosity. It is an effect that musicians, In other words, there is no affective curvature of instrument makers, and other music adjacent the string over the support. The string can be professions deal with on a conscious level. This considered to begin and end at the supports, can be seen in the form of instruments. One of and for any given instant the slope of the string the reasons the sound of a grand piano is pref- on the support is constant. erable to a console piano is because the longer strings lessen the inharmonicity. The less affect- Solving equation (1) will provide a prediction ed harmonic frequencies are then more resonant for the frequencies that will be carried by a stiff between different pitches, as the frequency rela- string in the form: tionships will be closer to simpler ratios. Piano tuners also deal with inharmonicity in a direct way. They will stretch the octaves of the piano, which causes the higher registers to sit Where n is the order of the harmonic. is the a little sharper than would be ideal. Of course, fundamental frequency of the string if it had no matters of musical perception are complicated, stiffness. This is governed by the equation: and any statement about what is good or prefer- able is bound to come with many caveats. Some say that the octave stretching on a piano help make it “livelier.” 2 The struggle with inharmonicity can also be seen in the form and function of guitars. Guitarists will often retune strings to make the overtones res- onate in a preferable way in a given key. The G B is a parameter that contains information about string, which is the thickest unwound string on a the physical properties of the string. standard electric guitar, is notorious for present- ing tuning difficulties for the guitarist. Its harmon- ics can sound harsh, and methods such as de- tuning the string slightly are employed to lessen the effect. Inharmonicity also helps to explain why bass guitars have much longer necks. Math- ematically, the low frequencies on a bass guitar There are some things to notice about the pa- could be achieved by maintaining the short scale rameter B in the frequency equation. B is the length of a standard guitar and increasing the parameter that describes the degree of inharmo- strings’ mass per unit length (thicker strings), nicity of a given string. As B is multiplied by the or by placing them under much less tension. square of the order of the harmonic, its effect is However, doing those two things would increase magnified for higher harmonics. Also, the rela- the inharmonicity of the strings to a degree that tionship for frequencies carried by an ideal string would border on unmusical. So, the design of an can be recovered by setting the string’s stiffness, instrument, in view of inharmonicity, becomes a E, to zero, which would make B zero, which balancing act between the factors that define it. would leave . Background The definition of B also shows that inharmonicity can be lessened by increasing the tension or the The foundations for this research were laid by length of the string, or it can be magnified by in- Rayleigh in his Theory of Sound in the 1870s3 18 ASTRA - The McNair Scholars’ Journal and further developed by Fletcher in the 1960s.1,4 instrument like a piano, are the main reason for The final form of the equations that we use come a level of inharmonicity great enough that the from Fletcher’s The physics of musical instru- inharmonicity of a single guitar strings can be ments, but he laid out the math in an earlier pa- perceptible to a listener. Järveläinen6 created lis- per1. In that paper, Fletcher measured the inhar- tening experiments for steel and nylon stringed monicity of a string for each note on a Hamilton guitars. Real recordings were used to create a upright piano. His measurements covered both parametric model of the guitar tones so that the the plain, monofilament strings that are found in inharmonicity of the tones could be controlled. the midrange and upper registers of the piano, Through the listening experiments, a threshold as well as the wound strings that are found in was found for the perceptibility of inharmonicity the lower registers of the piano. In the paper B that was close to typical values found on the gui- values were derived from the dimensions of the tar. It was also found that the inharmonicity was strings, as it was impractical to remove strings more or less detectable depending on whether from the piano to make measurements about or not the attack transients were cropped out. their properties. This led to difference in B calcu- This type of understanding of inharmonicity has lations between wound and plain strings. It was uses for digital instrument sound synthesis, found that there is an extra torque provided by where sound creators may want to be able to windings, and after all of the aforementioned is consider all the factors that make a certain tone accounted for, it was concluded that equation (2) sound realistic. gives a good approximation for the frequencies of the harmonics of each string. There is also an inharmonicity related explana- tion for the phenomenon of wound guitar strings Fletcher also notes that a previous paper of his “going dead” after some amount of playing time. found that “the excellence of the tone from a pi- When a string “goes dead,” it has a dull sound ano can not be said to be greater or less as the with shorter sustain. Houtsma7 found that this is value of B becomes greater or less. There must due to the increased inharmonicity of a well-used be an optimum value of B for each string and wound guitar string. Houtsma simulated the this value has not yet been found. It is certainly stretching and releasing that is done by playing not B=0, which would mean that all the partials a guitar string and found that it caused a mass should be harmonic.” redistribution that causes greater inharmonicity in the partials.
Load more

Recommended publications
  • 1785-1998 September 1998
    THE EVOLUTION OF THE BROADWOOD GRAND PIANO 1785-1998 by Alastair Laurence DPhil. University of York Department of Music September 1998 Broadwood Grand Piano of 1801 (Finchcocks Collection, Goudhurst, Kent) Abstract: The Evolution of the Broadwood Grand Piano, 1785-1998 This dissertation describes the way in which one company's product - the grand piano - evolved over a period of two hundred and thirteen years. The account begins by tracing the origins of the English grand, then proceeds with a description of the earliest surviving models by Broadwood, dating from the late eighteenth century. Next follows an examination of John Broadwood and Sons' piano production methods in London during the early nineteenth century, and the transition from small-scale workshop to large factory is noted. The dissertation then proceeds to record in detail the many small changes to grand design which took place as the nineteenth century progressed, ranging from the extension of the keyboard compass, to the introduction of novel technical features such as the famous Broadwood barless steel frame. The dissertation concludes by charting the survival of the Broadwood grand piano since 1914, and records the numerous difficulties which have faced the long-established company during the present century. The unique feature of this dissertation is the way in which much of the information it contains has been collected as a result of the writer's own practical involvement in piano making, tuning and restoring over a period of thirty years; he has had the opportunity to examine many different kinds of Broadwood grand from a variety of historical periods.
    [Show full text]
  • African Music Vol 6 No 2(Seb).Cdr
    94 JOURNAL OF INTERNATIONAL LIBRARY OF AFRICAN MUSIC THE GORA AND THE GRAND’ GOM-GOM: by ERICA MUGGLESTONE 1 INTRODUCTION For three centuries the interest of travellers and scholars alike has been aroused by the gora, an unbraced mouth-resonated musical bow peculiar to South Africa, because it is organologically unusual in that it is a blown chordophone.2 A split quill is attached to the bowstring at one end of the instrument. The string is passed through a hole in one end of the quill and secured; the other end of the quill is then bound or pegged to the stave. The string is lashed to the other end of the stave so that it may be tightened or loosened at will. The player holds the quill lightly bet­ ween his parted lips, and, by inhaling and exhaling forcefully, causes the quill (and with it the string) to vibrate. Of all the early descriptions of the gora, that of Peter Kolb,3 a German astronom­ er who resided at the Cape of Good Hope from 1705 to 1713, has been the most contentious. Not only did his character and his publication in general come under attack, but also his account of Khoikhoi4 musical bows in particular. Kolb’s text indicates that two types of musical bow were observed, to both of which he applied the name gom-gom. The use of the same name for both types of bow and the order in which these are described in the text, seems to imply that the second type is a variant of the first.
    [Show full text]
  • Lab 12. Vibrating Strings
    Lab 12. Vibrating Strings Goals • To experimentally determine the relationships between the fundamental resonant frequency of a vibrating string and its length, its mass per unit length, and the tension in the string. • To introduce a useful graphical method for testing whether the quantities x and y are related by a “simple power function” of the form y = axn. If so, the constants a and n can be determined from the graph. • To experimentally determine the relationship between resonant frequencies and higher order “mode” numbers. • To develop one general relationship/equation that relates the resonant frequency of a string to the four parameters: length, mass per unit length, tension, and mode number. Introduction Vibrating strings are part of our common experience. Which as you may have learned by now means that you have built up explanations in your subconscious about how they work, and that those explanations are sometimes self-contradictory, and rarely entirely correct. Musical instruments from all around the world employ vibrating strings to make musical sounds. Anyone who plays such an instrument knows that changing the tension in the string changes the pitch, which in physics terms means changing the resonant frequency of vibration. Similarly, changing the thickness (and thus the mass) of the string also affects its sound (frequency). String length must also have some effect, since a bass violin is much bigger than a normal violin and sounds much different. The interplay between these factors is explored in this laboratory experi- ment. You do not need to know physics to understand how instruments work. In fact, in the course of this lab alone you will engage with material which entire PhDs in music theory have been written.
    [Show full text]
  • 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.
    [Show full text]
  • Ellen Fullman
    A Compositional Approach Derived from Material and Ephemeral Elements Ellen Fullman My primary artistic activity has been focused coffee cans with large metal mix- around my installation the Long String Instrument, in which ing bowls filled with water and rosin-coated fingers brush across dozens of metallic strings, rubbed the wires with my hands, ABSTRACT producing a chorus of minimal, organ-like overtones, which tipping the bowl to modulate the The author discusses her has been compared to the experience of standing inside an sound. I wanted to be able to tune experiences in conceiving, enormous grand piano [1]. the wire, but changing the tension designing and working with did nothing. I knew I needed help the Long String Instrument, from an engineer. At the time I was an ongoing hybrid of installa- BACKGROUND tion and instrument integrat- listening with great interest to Pau- ing acoustics, engineering In 1979, during my senior year studying sculpture at the Kan- line Oliveros’s album Accordion and and composition. sas City Art Institute, I became interested in working with Voice. I could imagine making mu- sound in a concrete way using tape-recording techniques. This sic with this kind of timbre, playing work functioned as soundtracks for my performance art. I also created a metal skirt sound sculpture, a costume that I wore in which guitar strings attached to the toes and heels of my Fig. 1. Metal Skirt Sound Sculpture, 1980. (© Ellen Fullman. Photo © Ann Marsden.) platform shoes and to the edges of the “skirt” automatically produced rising and falling glissandi as they were stretched and released as I walked (Fig.
    [Show full text]
  • To the New Owner by Emmett Chapman
    To the New Owner by Emmett Chapman contents PLAYING ACTION ADJUSTABLE COMPONENTS FEATURES DESIGN TUNINGS & CONCEPT STRING MAINTENANCE BATTERIES GUARANTEE This new eight-stringed “bass guitar” was co-designed by Ned Steinberger and myself to provide a dual role instrument for those musicians who desire to play all methods on one fretboard - picking, plucking, strumming, and the two-handed tapping Stick method. PLAYING ACTION — As with all Stick models, this instrument is fully adjustable without removal of any components or detuning of strings. String-to-fret action can be set higher at the bridge and nut to provide a heavier touch, allowing bass and guitar players to “dig in” more. Or the action can be set very low for tapping, as on The Stick. The precision fretwork is there (a straight board with an even plane of crowned and leveled fret tips) and will accommodate the same Stick low action and light touch. Best kept secret: With the action set low for two-handed tapping as it comes from my setup table, you get a combined advantage. Not only does the low setup optimize tapping to its SIDE-SADDLE BRIDGE SCREWS maximum ease, it also allows all conventional bass guitar and guitar techniques, as long as your right hand lightens up a bit in its picking/plucking role. In the process, all volumes become equal, regardless of techniques used, and you gain total control of dynamics and expression. This allows seamless transition from tapping to traditional playing methods on this dual role instrument. Some players will want to compromise on low action of the lower bass strings and set the individual bridge heights a bit higher, thereby duplicating the feel of their bass or guitar.
    [Show full text]
  • Fretted Instruments, Frets Are Metal Strips Inserted Into the Fingerboard
    Fret A fret is a raised element on the neck of a stringed instrument. Frets usually extend across the full width of the neck. On most modern western fretted instruments, frets are metal strips inserted into the fingerboard. On some historical instruments and non-European instruments, frets are made of pieces of string tied around the neck. Frets divide the neck into fixed segments at intervals related to a musical framework. On instruments such as guitars, each fret represents one semitone in the standard western system, in which one octave is divided into twelve semitones. Fret is often used as a verb, meaning simply "to press down the string behind a fret". Fretting often refers to the frets and/or their system of placement. The neck of a guitar showing the nut (in the background, coloured white) Contents and first four metal frets Explanation Variations Semi-fretted instruments Fret intonation Fret wear Fret buzz Fret Repair See also References External links Explanation Pressing the string against the fret reduces the vibrating length of the string to that between the bridge and the next fret between the fretting finger and the bridge. This is damped if the string were stopped with the soft fingertip on a fretless fingerboard. Frets make it much easier for a player to achieve an acceptable standard of intonation, since the frets determine the positions for the correct notes. Furthermore, a fretted fingerboard makes it easier to play chords accurately. A disadvantage of frets is that they restrict pitches to the temperament defined by the fret positions.
    [Show full text]
  • Mersenne and Mixed Mathematics
    Mersenne and Mixed Mathematics Antoni Malet Daniele Cozzoli Pompeu Fabra University One of the most fascinating intellectual ªgures of the seventeenth century, Marin Mersenne (1588–1648) is well known for his relationships with many outstanding contemporary scholars as well as for his friendship with Descartes. Moreover, his own contributions to natural philosophy have an interest of their own. Mersenne worked on the main scientiªc questions debated in his time, such as the law of free fall, the principles of Galileo’s mechanics, the law of refraction, the propagation of light, the vacuum problem, the hydrostatic paradox, and the Copernican hypothesis. In his Traité de l’Harmonie Universelle (1627), Mersenne listed and de- scribed the mathematical disciplines: Geometry looks at continuous quantity, pure and deprived from matter and from everything which falls upon the senses; arithmetic contemplates discrete quantities, i.e. numbers; music concerns har- monic numbers, i.e. those numbers which are useful to the sound; cosmography contemplates the continuous quantity of the whole world; optics looks at it jointly with light rays; chronology talks about successive continuous quantity, i.e. past time; and mechanics concerns that quantity which is useful to machines, to the making of instruments and to anything that belongs to our works. Some also adds judiciary astrology. However, proofs of this discipline are The papers collected here were presented at the Workshop, “Mersenne and Mixed Mathe- matics,” we organized at the Universitat Pompeu Fabra (Barcelona), 26 May 2006. We are grateful to the Spanish Ministry of Education and the Catalan Department of Universities for their ªnancial support through projects Hum2005-05107/FISO and 2005SGR-00929.
    [Show full text]
  • Andrew Nolan Viennese
    Restoration report South German or Austrian Tafelklavier c. 1830-40 Andrew Nolan, Broadbeach, Queensland. copyright 2011 Description This instrument is a 6 1/2 octave (CC-g4) square piano of moderate size standing on 4 reeded conical legs with casters, veneered in bookmatched figured walnut in Biedermeier furniture style with a single line of inlaid stringing at the bottom of the sides and a border around the top of the lid. This was originally stained red to resemble mahogany and the original finish appearance is visible under the front lid flap. The interior is veneered in bookmatched figured maple with a line of dark stringing. It has a wrought iron string plate on the right which is lacquered black on a gold base with droplet like pattern similar to in concept to the string plates of Broadwood c 1828-30. The pinblock and yoke are at the front of the instrument over the keyboard as in a grand style piano and the bass strings run from the front left corner to the right rear corner. The stringing is bichord except for the extreme bass CC- C where there are single overwound strings, and the top 1 1/2 octaves of the treble where there is trichord stringing. The top section of the nut for the trichords is made of an iron bar with brass hitch pins inserted at the top, this was screwed and glued to the leading edge of the pinblock. There is a music rack of walnut which fits into holes in the yoke. The back of this rack is hinged in the middle and at the bottom.
    [Show full text]
  • Roger Sadowsky Interview, Bass Guitar Magazine UK
    ROGER THAT 028 BASS GUITAR MAGAZINE 028-030 Sadowsky_rev3JH.indd 28 13/07/2015 18:17 BASSISTS ROGER SADOWSKY Roger Sadowsky, one of the world’s leading bass luthiers, stopped by at the London Bass Guitar Show to talk to Mike Brooks about his bass building philosophy stroll around Olympia during the “I recommended a good fret job, shielding the London Bass Guitar Show can be electronics, a better bridge and a preamp – actually, a noisy experience to say the only the second bass preamp I had ever installed. I was least – yet on both days of this using a circuit by Stars Guitars from San Francisco, a year’s event back in March, group that had come out of the Alembic school. That’s A there was a tangible buzz: an what I gave Marcus – but within a year, they went out audible sound of hushed of business and Marcus’s preamp died! They told me mutterings between those in attendance. “It is him, when they were closing up that the closest thing to isn’t it?”... “Is that really him? Here in London?” what they were making was a Bartolini TCT preamp. Who could they have been talking about, you ask? I used that until 1990, when I wanted to create my Well, yes it was true – one of the premier luthiers outboard preamp box and Alex Aguilar [of Aguilar of the bass world was there at the London Bass fame] helped me to design my own circuit.” Guitar Show, and boy did Roger Sadowsky make a Back in those days, there was no internet or social splash.
    [Show full text]
  • Extracting Vibration Characteristics and Performing Sound Synthesis of Acoustic Guitar to Analyze Inharmonicity
    Open Journal of Acoustics, 2020, 10, 41-50 https://www.scirp.org/journal/oja ISSN Online: 2162-5794 ISSN Print: 2162-5786 Extracting Vibration Characteristics and Performing Sound Synthesis of Acoustic Guitar to Analyze Inharmonicity Johnson Clinton1, Kiran P. Wani2 1M Tech (Auto. Eng.), VIT-ARAI Academy, Bangalore, India 2ARAI Academy, Pune, India How to cite this paper: Clinton, J. and Abstract Wani, K.P. (2020) Extracting Vibration Characteristics and Performing Sound The produced sound quality of guitar primarily depends on vibrational char- Synthesis of Acoustic Guitar to Analyze acteristics of the resonance box. Also, the tonal quality is influenced by the Inharmonicity. Open Journal of Acoustics, correct combination of tempo along with pitch, harmony, and melody in or- 10, 41-50. https://doi.org/10.4236/oja.2020.103003 der to find music pleasurable. In this study, the resonance frequencies of the modelled resonance box have been analysed. The free-free modal analysis was Received: July 30, 2020 performed in ABAQUS to obtain the modes shapes of the un-constrained Accepted: September 27, 2020 Published: September 30, 2020 sound box. To find music pleasing to the ear, the right pitch must be set, which is achieved by tuning the guitar strings. In order to analyse the sound Copyright © 2020 by author(s) and elements, the Fourier analysis method was chosen and implemented in Scientific Research Publishing Inc. MATLAB. Identification of fundamentals and overtones of the individual This work is licensed under the Creative Commons Attribution International string sounds were carried out prior and after tuning the string. The untuned License (CC BY 4.0).
    [Show full text]
  • An Exploration of Monophonic Instrument Classification Using Multi-Threaded Artificial Neural Networks
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 12-2009 An Exploration of Monophonic Instrument Classification Using Multi-Threaded Artificial Neural Networks Marc Joseph Rubin University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Computer Sciences Commons Recommended Citation Rubin, Marc Joseph, "An Exploration of Monophonic Instrument Classification Using Multi-Threaded Artificial Neural Networks. " Master's Thesis, University of Tennessee, 2009. https://trace.tennessee.edu/utk_gradthes/555 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Marc Joseph Rubin entitled "An Exploration of Monophonic Instrument Classification Using Multi-Threaded Artificial Neural Networks." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Computer Science. Jens Gregor, Major Professor We have read this thesis and recommend its acceptance: James Plank, Bruce MacLennan Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a thesis written by Marc Joseph Rubin entitled “An Exploration of Monophonic Instrument Classification Using Multi-Threaded Artificial Neural Networks.” I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Master of Science, with a major in Computer Science.
    [Show full text]