Glass Tube Gamelan Design for Preparation On

11. REFERENCES reality,” in IEEE VR Workshop on Trends and Issues GLASS TUBE GAMELAN DESIGN FOR PREPARATION in Tracking for Virtual Environments, G. Zachmann, [1] D. A. Butler, S. Izadi, O. Hilliges, D. Molyneaux, Ed. Aachen: Shaker Verlag, 2007, pp. 44–51, ON INSTALLATION ART APPLICATIONS S. Hodges, and D. Kim, “Shake’n’sense: reducing vortrag: IEEE Virtual Reality 2007, Charlotte, interference for overlapping structured light depth NC (USA); 2007-03-14 – 2007-03-17. [Online]. Tsung-Ching Liu Cheng-Han Yang Bing-Shr Yan cameras,” in Proceedings of the 2012 ACM Available: http://publik.tuwien.ac.at/ﬁles/pub-inf Chinese Culture University, Taipei Chinese Culture University, Taipei Chinese Culture University, Taipei annual conference on Human Factors in Computing 5236.pdf Systems, ser. CHI ’12. New York, NY, USA: Electrical Eng. Department Electrical Eng. Department Inst. of Digital Mechtronics ACM, 2012, pp. 1933–1936. [Online]. Available: [10] J. C. Schacher, “Motion To Gesture To Sound : http://doi.acm.org/10.1145/2208276.2208335 Mapping For Interactive Dance,” in Proceedings of the International Conference on New Interfaces for [2] C. C. Holt, “Forecasting seasonals and trends Musical Expression, 2010, pp. 250–254. [Online]. by exponentially weighted moving averages,” Available: http://www.nime.org/proceedings/2010/ ABSTRACT In interactive music applications Max/Msp is extensively used. The connecting apparatus such as sensors International Journal of Forecasting, vol. 20, nime2010 250.pdf Scale plays important role in musical instrument design. combined with microprocessor interface are used for no. 1, pp. 5 – 10, 2004. [Online]. Avail- Harmonic instruments adopt 12-tet (12 tone equal human (haptic or non-haptic) to interact with the able: http://www.sciencedirect.com/science/article/ [11] A. Schmeder, A. Freed, and D. Wessel, “Best prac- temperaments) scale, and non-harmonic instruments use computer music (Max/Msp) running on a PC. It pii/S0169207003001134 tices for open sound control,” in Linux Audio Con- scales typically from 5 to 7 notes to the octave with frequently involves graphic image into this interactive ference, Utrecht, NL, 01/05/2010 2010. uneven intervals in general such as gamelan [1]. scenario. Namely, human interact with certain computer [3] B. K. P. Horn, “Closed-form solution of absolute [12] A. Stelzer, K. Pourvoyeur, and A. Fischer, “Concept graphic image so as to create computer music of some orientation using unit quaternions,” J. Opt. Soc. In this paper, we were dealing with a particular non- and application of lpm - a novel 3-d local position sense. One of these types is the virtual instrument APP Am. A, vol. 4, no. 4, pp. 629–642, Apr 1987. harmonic instrument design where a set of equal size measurement system,” Microwave Theory and Tech- popular in iPad or smart phone. [Online]. Available: http://josaa.osa.org/abstract. glass tubes filled with water of different levels to create niques, IEEE Transactions on, vol. 52, no. 12, pp. cfm?URI=josaa-4-4-629 scale for installation art application. The level is properly 2664 – 2669, dec. 2004. In installation art application we would also be interested adjusted based on a calculated dissonance measure. We [4] A. Hunt, M. M. Wanderley, and M. Par- in controlling real instrument playing by computer graph. will first review the work by Promp and Levelt’s [2] adis, “The importance of parameter mapping [13] G. Vigliensoni and M. M. Wanderley, “A quantita- Automatic musical instrument playing has existed over mathematical model that utilizes dissonance curve of in electronic instrument design,” in Proceed- tive comparison of position trackers for the devel- 100 years addressed in precisely playing back the music sound to find the proper music scale for non-harmonic ings of the 2002 conference on New inter- opment of a touch-less musical interface,” in Pro- score in a formal way. But for graphic control of playing sounding material. The model is adjusted to fine tune the faces for musical expression, ser. NIME ’02. ceedings of the International Conference on New In- by human it relies on ergonomic interactive factors. measure and is tested by verifying a real xylophone terfaces for Musical Expression (NIME), G. Essl, Using graphic image to play instrument is hard. Even a Singapore, Singapore: National University of bought from Java islands. We then use this model to do a B. Gillespie, M. Gurevich, and S. O’Modhrain, Eds. trained musician is not able to control the computer Singapore, 2002, pp. 1–6. [Online]. Available: preliminary design of our water filled glass tube Ann Arbor, Michigan: University of Michigan, May graph easily to precisely playing back the music piece. http://dl.acm.org/citation.cfm?id=1085171.1085207 instrument. It has shown the glass tube instruments have 21-23 2012. For general public who lack of any musical instrument TM 7-note scales that resemble a Pelog gamelan but with [5] iPi Soft, LLC, “iPi Motion Capture ,” http://www. playing training it will be worse. So for our purpose to uneven intervals. And quite opposite to people’s view ipisoft.com/, accessed: 12/01/2013. [14] A. D. Wilson and H. Benko, “Combining multiple provide the graphic image controlling the real music that the higher the water level the lower the pitch. It is depth cameras and projectors for interactions on, playing in recreation ground, a kind of music [6] A. Maimone and H. Fuchs, “Reducing interference because higher water level tends to smooth the vibration above and between surfaces,” in Proceedings of the instruments called gamelan has drawn our attention. A between multiple structured light depth sensors us- cycle of the glass. The design procedure can be served as 23nd annual ACM symposium on User interface gamelan is a traditional musical ensemble from a reference for building much larger tube (glass or PVC) ing motion,” in Virtual Reality Short Papers and software and technology, ser. UIST ’10. New Indonesia, typically from the islands of Java and Bali, placed in park or recreation ground for intelligent living Posters (VRW), 2012 IEEE, march 2012, pp. 51 –54. York, NY, USA: ACM, 2010, pp. 273–282. featuring a variety of non-harmonic instruments. Their application. 1 [7] Microsoft, “Microsoft KinectTM for Windows,” http: [Online]. Available: http://doi.acm.org/10.1145/ music scales do not follow the common 12-tet scale but 1866029.1866073 have only 5 to 7 notes to the octave and has fascinating //www.microsoft.com/en-us/kinectforwindows/, ac- 1. INTRODUCTION cessed: 12/01/2013. spiritual and meditation effect when sounding. The [15] D. Zicarelli, “An extensible real-time signal process- Musical instruments can be dichotomized into harmonic selection of frequencies (intervals) for each scale was [8] P. Modler, “Neural Networks for Mapping Hand ing environment for max,” in Proceedings of the and non-harmonic sounding structure. Instruments like evolved over thousands of years to make consonant Gestures to Sound Synthesis Parameters,” in Trends International Computer Music Conference (ICMC guitar, piano, harpsichord and violin belong to the sound when playing. With less notes in scale and way of in Gestural Control of Music, M. Wanderley, Battier, 1998). Ann Arbor, Michigan: MPublishing, Uni- stringed type harmonic instrument because the spectra of music style, gamelan is easy to play and is feasible to Ed. IRCAM, Paris, 2000. versity of Michigan Library, 1998. a sounding note are almost equally spaced integer install in graphic control scenario. In the following, we multiple harmonics of the fundamental frequency. The are aiming at a preliminary type of gamelan design that [9] T. Pintaric and H. Kaufmann, “Affordable infrared- fundamental frequency decides the pitch of the sound, has used common glass tubes of equal size filled with optical pose tracking for virtual and augmented whereas the adscititious harmonics (or overtones) water to adjust levels followed the theoretical consonant constituent the timbre of each particular instrument. measure analysis to create scale.

Non-harmonic instruments cover percussion type of Section 2 shows the difference of the harmonic and non- instruments, like the hang, gongs, xylophone, certain harmonic instruments in spectral analysis point of view. type of cymbals and metallophones. The spectra of the Section 3 reviews the concepts of instrument scale. sound played by those instruments do not follow the Section 4 deals with the consonance (or dissonance) equally spaced integer multiple of harmonic pattern, and measure related to scale design, especially the work done are irregularly spread peaks over the entire frequency by Promp and Levelt. Then an adjusted formula is domain. proposed to fine tune the measure. A Xylophone gamelan purchased from Indonesia is tested for validity based on the adjusted measure analysis. This is then 1 applied to the glass tube gamelan design in Section 5 This work is supported in part by the National Science Council under Grant 101-2221-E-034-012 followed by the concluding remark in Section 6.

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2. THE HARMONIC AND NON-HARMONIC sounds when the length of the two string are in the ratio we measure dissonance? Figure 8 shows the mixing of INSTRUMENTS 3/2 whereas the musical fourth sounds when the ratio of two sinusoids with one fixes to 220 Hz and another + sweeps from 220 Hz to 470 Hz. The mixing creates beat 2.1 Harmonic instrument the strings is 4/3. So for the “Do” it has frequency f0 −L R 4 pattern with human listening to the sound to express =261.6 Hz, “Fa” has f × = 348.8 Hz and “So” has The sound of plucking a string of guitar or piano would −L 0 their feeling. There are three stages of feeling: At Z 3 create a spectrum like Figure 1 [3] where equally spaced beginning with few Hz difference of the indiscernible 3 two tones (small beats), it’s a pleasant feeling. Then goes multiple harmonics spread in a descending order over the frequency f0 × = 392.4 Hz. Table 1 shows the intervals Figure 3. The waveguide digital filter model of guitar. 2 entire frequency range. The first peak is the fundamental into the second stage, rough feeling as the beat frequency The L is the number of wave-guide element 12 frequency of the note which contributes to the pitch of of a 12-tet scale where a= 2 . increases, and finally the last stage where two (delays) denoted in Z −L that determines the the sound, whereas the higher frequency components discernible frequencies are heard but with pleasure. pitch of the sound. contribute to the timbre of the sound. Since a pure 1 1 2 3 4 5 6 7 8 9 10 11 12 =2 a a a a a a a a a a a a sinusoid has a DFT spectrum like Figure 2. So the guitar To create a decay type amplitude spectrum as in Figure 3, Do Do# Re Re# Mi Fa Fa # So So # La La# Si Do (hi ) sound can be considered as made of multiple sinusoids a Low Pass Filter (LPF) is added (that has create a small ↑ ↑ with descending amplitudes. It is because of the higher delay δ), together with a fine tune all pass filter (Fig. 4) 261.6Hz 440Hz harmonics (overtones) that makes the sound much (phase delay λ that is less than one unit) to adjust the Table 1. The 12-tet scale. pleasant than a pure single sinusoid does. This fundamental frequency of each interval to reach the true phenomenon is similar to the pianos. Figure 8. Mix of two sinusoids, one with a fixed 220Hz scale. The one octave “Do” is double the frequency of the and another sweeps from 220 Hz to 470 Hz to

lower “Do”. Therefore for 10-tet scale we adopt a= 10 2 Input output create the beat frequency from small to large. and there are 10 intervals counting from the lower “Do” + LPF all pass filter to higher “Do”. There is another representation for −L 4.1 Sensory dissonance curves R interval called “cent” [4]. It is to subdivide one octave − L into 1200 parts, and one part is one “cent”. The Plomp and Levelt [2] select 90 volunteers to conduct the Z following table (Table 2) describes the relation between experiment described above. The dissonance is marked Figure 4. Guitar model with fine frequency tuned pitch. “ratios” and “‘cents”. Since there are 12 semi-tones then from 1 to 7, 1 represents the most dissonance and 7 each semi tone differs by 100 cents. represents most consonance. Figure 9 shows the 2.2 Non-harmonic instrument dissonance curve made by averaging the weighting ratio 1:1 r:1 2:1 survey. Both ratios and frequencies are shown in the Non-harmonic instrument music exists in natural world. log ratio 0 log (r) log (2) intervals. Figure 1. A typical magnitude spectrum of the sound by Striking the stones in Chaco valley of New Mexico in 1200 plucking a string of guitar. North America will sound musical rhythm with scales. cents 0 log(r) 1200 log(2) Similarly, by striking different part of metal bar, iron bar and oil tank also create scale of music sound. Among them a formal type of instrument is gamelan. Gamelan is Table 2. “Ratio” to “Cents” conversion table. popular in Indonesian Java island, similar to ancient Chinese Gong and bells is a kind of percussion For example, the Slendro gamelan [5] (Figure 6) and Pelog [6] (Figure 7) have scale intervals as below: instrument. For example, the Tisngshaw Bell originated Figure 9. Two sinusoidal tones are mixed with one fixed in from Tibet a thousand years ago has spectrum like 0 231 474 717 955 1208 cents 400Hz and one sweeps from 400Hz and up. The Figure 5. It is obvious that frequency components (peaks) sensory dissonance curve is drawn by averaging do not follow the integer multiple of fundamental the 90 people’s survey. The caption in the x-axis frequency. We name this type of instrument as non- shows that sweeping from 400Hz to 424Hz (small harmonic instrument, and it also cannot be synthesized beats, few Hz) is in the pleasant area; from 424Hz by the wave-guide digital filter models as in Figures 3 to 500 Hz (over 24Hz and less than 100Hz beats) is and 4. Figure 6. The scale of a Slendro gamelan in the rough area and above 500 Hz(over 100Hz Figure 2. Spectrum of a pure sinusoid shown with beats) reaches consonance area again [2]. digital frequency in the x-axis. In cents: 0 120 258 539 675 785 943 1206 Plomp and Levelt also made a multiple experiments For wind instruments like clarinet, they also constituent based on different base (fixed) frequency. It turns out that the lower the base frequency the broader the curve almost equally spaced integer multiple of harmonics of each note playing except few of them slightly deviate which means larger unpleasant area. We use their graph from integer. We group all these types of instruments as Figure 7. The scale of a Pelog gamelan. depicted below (Fig. 10): harmonic musical instrument. In computer music analysis, we have a so called comb filter as depicted in For the harmonic instrument, the designed scale with Figure 4 to synthesize a guitar [3] as an example. The even intervals is about right. This is simply not the case

spectrum of the impulse response of Figure 4 has poles Figure 5. The spectrum of Tingshaw Bell. for non-harmonic instrument gamelan. We have the at integer multiple of the fundamental frequency with reason to explain this by the discussion on section 4. equal amplitude peaks. Even the spectrum peaks do not 3. THE MUSIC SCALE decay as frequency goes up as the real guitar spectrum 4. THE CONSONANCE OR DISSONANCE does, its voice sounds like an electric guitar. From this The music scale is described by ratio as early in the CURVE FOR SOUNDS

model the fundamental frequency is f / 2Lwhere f the Pythagorean time. For example, a string fretted at its s s halfway point sounds an octave above the unfretted Consonance or dissonance measure of sound is ascribed Figure 10. A normalized dissonance curves (sensory sampling frequency and 2L is the number of delays it string, and so the octave is given by the ratio two to one, to human’s ear. How 12-tet is consonant to human? Why dissonance) of two sinusoids tested with travelled. written 2/1. Pythagoras found that the musical fifth gamelan gives spiritual and meditation effect? How do different base frequencies [2].

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the measure in (5) as the first run in a theoretical way intermediate steps. The graph created is so called the Fill one glass tube with water level up to almost full. 4.2 Dissonance curve between notes of instrument searching for those αk such that DF (αk ) are locally Sensory Dissonance Curve in Figure 13. (6) is then used Record the striking sound; perform the FFT to create the minima, and then fine tune the measure experimentally to fine tune the minimum dissonance measure, and the amplitude spectrum in Figure14. For non-harmonic instrument multi-tones are irregularly through those minimal points from (5). The modification five intervals are (1, 1.114, 1.27,1.42, 1.56), which is spanned over the entire frequency range. For example of (5) is to measure close to the 12-tet scale’s interval Do, Re, Mi, Fa#, note “F” covers N fi (partials) (N sinusoidal tones), with So#( 1, 1.122, 1.260, 1.412, 1.58). The sound created by N N striking the bars of the Xylophone shows that their intensity ai ; Note “G” covers N g j partials with ~ ~ ~ = + D~ + , (6) pitches match the analysis. This shows the DSP analysis DF(αk ) DF F ∑∑ d( fi , f j ,li , l j ) intensity b j , then the dissonance measure between note i=1 j=1 of the design strategy is coincident to the ancient “F” and note “G” is ~ ~ ~ ~ ~ people’s design but in a more scientific way instead of where F ={αk f1, f2  fN}, αk = f1 / f1 and f1 and f1 spiritual evolvement over thousands of years. are the dominant (fundamental) frequencies of each N N 1 ~ ~ D = d( f , g ,a ,b ) , (1) playing notes. f j , l j , j = 2N are obtained from the F,G 2 ∑∑ i j i j i=1 j=1 spectrum we measured experimentally based on the ~ where d( f , g ,a ,b ) is the pair-wised sinusoids dominant fundamental frequency f . The locally fine i j i j 1 Figure 14. The spectrum of the sound created by dissonance measure. It is obvious that using look-up ~ tune optimal is to find αk such that Min DF (αk ) is met. striking the short glass tube with water table to find out the dissonance measure is not practical level almost full. The horizontal axis shows for analysis. Therefore Plomp-Levelt [2] had modeled Based on the above analysis, we summarize the non- the real frequency in Hz. the curve of Figure 9 by the mathematical formula harmonic instrument design procedure below: −b x −b x d(x) = d(x) = e 1 − e 2 (2) (1) Select the material or sound we need (use the lowest Then select 5 principal components. The intensity of x stands for the absolute interval distance between the tone as base). components are normalized to have the strongest (2) Strike (play) it and record the sound in .wav or .mp3 component is 1. Based on the five components we derive two sinusoids. b1 , b2 decides the rising and falling rate file. the Sensory Dissonance Curve below (Figure 15). It is of the curve. Using gradient method they found b1 =3.5 (3) Find its spectrum (FFT) by Matlab. Figure 12. The spectrum of the sound created by the obvious that there are 7 minima between 1 and 2, i.e., the and b2 =5.75 。 Furthermore, they made an adjusting (4) Simplify the spectrum by selecting the principal longest metal bar of the Xylophone. scale has 7 intervals in one octave. After fine tune we factor so as to cover all the multiple curves (Figure 10) components for dissonance calculation. derived the intervals at ratio 1.107, 1.214, 1.405, 1.51, with different base frequency that the curves turn to (5) Find and plot the whole range Sensory Dissonance 1.75, 1.934. The first glass tube has pitch similar to an broader as base frequency drops. So Curve, locate the minimal points and then fine tune octave “Si” in electric organ with frequency 11 the measure to find the true minima as the scale for 261.6× 2×12 2 = 987.67 Hz. The rest are calculated −b s( f − f ) −b s( f − f ) this instrument. d( f , f ,l ,l ) = l [e 1 2 1 − e 2 2 1 ] . (3) and compared with 12-tet in table 3. 1 2 1 2 12 (6) Based on the derived scale to make instrument. x* And s = , l = min ( l , l ), x* is the interval 12 1 2 5. GAMELAN ANALYSIS AND FABRICATION s1 f1 + s2 (frequency ratio) where the largest dissonance occurs. * 5.1 Chrome metal bar gamelan Xylophone for From (3) they obtain =0.24, =0.021 and =19. x s1 s2 analysis purpose

The dissonance of a single note “F” of a particular To verify the effectiveness of the designing procedure instrument with frequency contains Ff ={f1, f2 … fN} described in last section, we bought a chrome metal bar Figure 13. Sensory Dissonance Curve of the Xylophone gamelan Xylophone (Figure 11) for testing. and intensities of each partial l j, j =1,2,N is 5.2 Glass tube gamelan calculated as N N 1 Since our design purpose is for common use in park and Figure 15. Sensory Dissonance Curve of short glass tube. D = d( f , f ,l ,l ) . (4) F ∑∑ i j i j play ground the cost is of the main concerning issue. It 2 i=1 j=1 has to be cheap and easy to fabricate. So instead of Listening to the sound created by short glass gamelan (4) is called the self dissonance of note “F” or intrinsic fabricating different size glass tubes, we are apt to and electric organ, we can hear the difference between dissonance. Therefore, the dissonances of playing “F” choose equal size glass tubes but allow water levels to the two. and α distance from “F”, "αF" covers three facets: adjust the pitches of the sound. Opposite to our common D , D and D . We sum them together sense that the tube filled with higher water level creates 12- tet 987. 1108 1244 1318 1479 1661 1864 F αF F ,αF scale 67Hz .622 .39 .38 .833 .06 .473 N N Figure 11. The chrome metal bar gamelan Xylophone lower pitch. It is because the higher water level inside Hz Hz Hz Hz Hz Hz D (α)= D + D + d( f ,αf ,l ,l ) . (5) used for testing validity of dissonance the tube tends to smooth more the vibration of glass Short 983. 1088 1194 1393 1563 1721 1902 F F αF ∑∑ i j i j when stroked. glass 606 .992 .379 .442 .934 .311 .294 i=1 j=1 measure. tube Hz Hz Hz Hz Hz Hz Hz Approximately, for harmonic instruments the spectrum gamelan We show our design by choosing two different size tubes of higher note (interval) can be considered as the lower We first perform the sound recording created by striking for testing: (i) short glass tube (common cups) (ii) long note spectrum transposed to the higher range. Namely the longest metal bar. Then 150k point FFT is calculated. Table 3. The frequency comparison chart between the glass tube (Height: 27.5cm Diameter: 4.7cm) relative frequency distance between each principal The sampling rate is 44.1k and the resulting amplitude short glass tube gamelan and 12-tet scale.

component and each component’s intensities are spectrum is plotted in Figure 12. We then choose 5 5.2.1 Short glass tube analysis and gamelan unchanged. This is not quite precise for non-harmonic principal components to represent the sound that are With the chosen short glass tubes it was found that the fabrication instrument that they have slight deviation both in used to plug into formula (5) to calculated the highest pitch we can get is only up to the fifth scale. At

frequency and intensity for different notes. So we treat dissonance for eachα as it spans from 1 to 4 with 0.01 this interval, the water level almost reaches half of the

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frequency and intensity for different notes. So we treat dissonance for eachα as it spans from 1 to 4 with 0.01 this interval, the water level almost reaches half of the

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glass tube, and we can no longer increase the pitch no matter how far we reduce the water level below the half ELECTRONIC CIRCUIT BUILDING IN PERU: A SUBALTERN CASE ON level, the pitch stays the same. The five interval scale PARTICIPATION AND TECHNOLOGY created by the short glass tube gamelan is shown in the Figure 16. José Ignacio Lopez Ramirez Gaston Pontificia Universidad Catolica del Peru Escuela de Música [email protected]

Figure 19. The final long glass tube gamelan with short glass tube gamelan placed in front of them for ABSTRACT electronic musician never made it into the Peruvian comparison. scene, and the history of electroacoustic music in Peru, In this paper we take a brief look at the history of circuit and related sound arts, is full of holes and struggles. Figure 16. The final short glass tube gamelan. In this set up, similarly, we can only find 6 intervals for the 7-note scale (Figure 19). Namely the highest pitch building for musical performance in Peru and examine Even thought we have had in the past professionally 5.2.2 Long glass tube analysis and gamelan we can reach is only up to the sixth note. At this point, its current status, focusing particularly on the attempts trained musicians, that could claim the have the fabrication made during the last decade to generate a local popular credential to belong to the western culture of the the water level has already reached half of the tube, and 3 there is no way of pitch increase by reducing water level. electronic musical scene derived from the use of home educated sound arts; for the most part, the Follows the similar procedure as in 5.2.1, we obtain the made sound generating electronic devices. contemporary Peruvian electronic musician and sound spectrum (Figure 17) of the long glass tube and the 6. CONCLUDING REMARK Acknowledging the historical shortages common to artist is part of the age of “the rise of the amateur”, and resultant Sensory dissonance curve (Figure 18) by using many subaltern societies and their role in the is, at best: a professional amateur [7]. Scale of non-harmonic percussion instrument normally development of Peruvian sound arts, I examine here a 5 principal components of Figure 17. Then perform the During the last decade, the constant drop on the price of possesses fewer notes to the octave than 12-tet scale as social history from below1 that serves as social fine tune to derive the intervals of ratio 1.184, 1.27, 1.39, consumer level computers, software piracy becoming a that of a harmonic instrument does. Interval of scale has commentary for the Peruvian electronic musical scene 1.44, 1.64 and 1.84. Table 4 is the frequency social standard, and a wider access to the Internet, have to be properly chosen to create consonant sound. We and the development of particular musical identities. To comparison chart between the long glass tube gamelan democratized the ‘right of entry’ for electronic have shown that equal size glass-tube filled with this aim, I argue for the necessity to apply alternative and 12-tet scale. musicians in Peru. However, lacking a complete different level of water can be served as a type of educational strategies tailored to meet the needs of a intellectual and participative history of electronic music gamelan for recreation play ground applications. The new generation of Peruvian musicians; strategies that has kept Peruvian musicians from achieving a more levels are adjusted based on a modified dissonance can make this shortages not a deficiency but an conceptually ‘advanced’ understanding of the measure. Two types of glass-tube were tested. Analysis opportunity. shows that they resemble a Pelog type gamelan and possibilities left to us by the electronic music revolution possess a 7-note scale but with uneven intervals. Both I present at the end of this paper a case report: a of the 1950s. workshop I developed in 2012 at the Escuela de Musica tubes have similar spectrum pattern at different pitch Musicians in South America, and Peru in this case, of the Pontificia Universidad Catolica del Peru, range. We also found that in order to generate all 7 interested in electronic music or related musical styles; PUCP), in Lima.2 This workshop was dedicated to the intervals we need to further increase the height of tubes find it difficult to buy the equipment necessary to fabrication of basic electronic circuits for sound we used. We had gained knowledge of sounding water replicate foreign musical trends that are based or generation. The intention was twofold: (1) to provide 4 filled glass-tube that higher water level creates lower dependant in technological gear. Also, if we consider the student with basic technical knowledge for the pitch is quite opposite to people’s thinking, but it that technological products could be linked to the social Figure 17. The spectrum of the sound created by development of musical instruments non dependant on remains further investigation effort such as mathematical contexts in which they are imagined, constructed and striking the long glass tube with water level their economical possibilities; and (2) to open the analysis of the glass vibration pattern related to tone, as used, many of these products would not belong in the almost full. students conceptually to forms of composition and well as the integration of control apparatus like Peruvian musical environment. Current academic performance not currently discussed or present in their Max/Msp and microprocessor (Arduino) in real-time discussions about issues related to the social, educational or social environments. interactive operation in the future. economical and technological relations between develop and developing countries are widespread. Postcolonial, 7. REFERENCES subaltern, critical and cultural studies, as well as New Musicology, are some of the academic settings where [1] Gamelan, 1. INTRODUCTION the condition of non-elite social groups becomes an ''http://zh.wikipedia.org/wiki/%E7%94%98%E7%B integral element in the construction and understanding E%8E%E8%98%AD” wiki. Musical communities and their identities are, in part, [2] Plomp and Levelt “Tonal consonance and constructed based on the technological currency present of history. So far, still, the musical academic critical bandwidth" J. Acoust. Soc. Am.38, 548- in the environments were they flourish. While particular environments of Peru have lacked, for the most part, 560 (1965). marketing strategies produce a craving for specific interest in these issues and maintain a conservative musical tools, these strategies not always take under approach to academic training. Computer Music and [3] Ken Stieglitz “A Digital Signal Processing Primer- related areas have yet to find a place in the Peruvian Figure 18. Sensory Dissonance Curve of long glass tube. consideration the economical conditions in developing with Applications to Digital Audio Computer academic world. In recent years I have started to countries. Some historical ‘tools of the trade’ of the Music” Addison-Wesley Publishing, p.112. mention and discuss these concerns in academic 12-tet 698. 783. 879. 932. 1046.4 117 1318. 388 914 914 236 00Hz 4.54 381Hz [4] Alexander J. Ellis Wiki. 1 The term ‘history from below’, coined by Georges Lefebvre, 3 Hz Hz Hz Hz 4Hz http://en.wikipedia.org/wiki/Cent_(music). is used, in this case, to refer to the condition of Peruvian For information on the history of Latin American long 614. 724. 775. 848. 885.53 100 1128. [5] Slendro: http://en.wikipedia.org/wiki/Slendro. electronic musicians in front of the electronic musical scenes electroacustic music see also Ricardo Dal Farra’s Latin glass 75 527 756 94 3 Hz 0.19 681Hz and academic opportunities present only inside the developed American Electroacoustic Music Collection at: tube Hz Hz Hz Hz 8Hz [6] Pelog http://en.wikipedia.org/wiki/Pelog. world’s radar. www.fondation-langlois.org/html/e/page.php?NumPage=556 Table 4. The frequency comparison chart between the 2 4 The workshop, a summer class at PUCP, was moved While more research needs to be made about this, a similar long glass tube gamelan and 12-tet scale. afterwards to my home and became an open space where the case can probably be made about Ecuador and Bolivia, but not students continue to experiment with circuit building. necessarily about Argentina and Chile.

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