A Digital Bagpipe Chanter System to Assist in One-to-One Piping Tuition Duncan W. H. Menzies Andrew P. McPherson Centre for Digital Music Centre for Digital Music Queen Mary University of London Queen Mary University of London London, UK London, UK [email protected] [email protected] ABSTRACT can convey their own interpretations of the otherwise large- ly inflexible traditional repertoire. This paper describes an electronic bagpipe chanter inter- Communicating such subtle temporal deviations can be a face and software system, developed to assist in one-to- challenging task for piping tutors. While singing or play- one Highland piping tuition. The chanter employs infrared ing a passage for the student to repeat is undoubtedly ef- reflectance sensors to detect the continuous movements of fective, it is often necessary for the teacher to verbally de- the player’s fingers, and incorporates an air pressure sen- scribe their intentions. This can lead to the use of some- sor in place of the chanter reed, allowing it to be connected what abstract language such as “push out the first beat” and to a traditional acoustic set of pipes. The software is in- “the G gracenote takes you to the E doubling on the beat”, tended to assist the instructor in communicating feedback which can be difficult to understand, even for students with to the student by providing facilities for recording, play- significant experience of other musical instruments. back, visualisation and comparison of teacher and pupil The aim of this work is to develop teaching tools which performances. A user study of the system was carried are specifically tailored to the requirements of the piping out with an experienced piping instructor and seven stu- community, with the goal of assisting and accelerating the dents. The sessions yielded encouraging and constructive learning process in the context of one-to-one lessons. This feedback from both students and instructor, and produced paper presents a digital GHB chanter interface and accom- promising avenues for further work. panying software system which enables the recording, play- back, visualisation and comparison of teacher and pupil 1. INTRODUCTION performances. This is intended to help the instructor illus- trate and convey feedback to the student. The Great Highland Bagpipe (GHB) is widely regarded, at least among pipers, as an instrument with a high barrier to entry. The Highland piping tradition requires the aspiring 2. RELATED WORK player to memorise a diverse array of distinct and formally 2.1 Electronic Bagpipes defined ornamentation techniques before attempting all but the simplest of tunes; a process that can often take six to Several brands of electronic Highland bagpipes are com- twelve months of regular and disciplined practice. Histor- mercially available, of which the DegerPipes 1 , Techno- ically, bagpipe music was passed on through the instructor Pipes 2 and Redpipes 3 are most prominent. These use sin- singing to the student in a precise musical language known gle capacitive touch-switches in place of the finger-holes, as canntaireachd. Indeed, piping notation is a compara- which are binary in nature; the “holes” are always either tively recent development, having been introduced in the fully open or closed. This does not accurately reflect the early 19th century [1]. The use of sheet music in bagpipe finger-holes of an acoustic chanter, which can be gradually lessons is now reasonably common. Nonetheless, GHB covered and uncovered to slide between notes. music is generally devoid of any phrase markings or other There have been several attempts within the academic high level performance instructions of the kind that might community to develop alternatives to this discrete sensor be seen in classical music notation. strategy. The FrankenPipe [2] uses photoresistors mounted The GHB provides no facility for dynamic control, and inside the holes of an acoustic GHB chanter. This provides produces a constant, uninterrupted sound, preventing the a wide analogue range for each hole, and has the advantage use of silences or timbral changes for the purposes of em- of retaining the physical feel of a traditional chanter. The phasis or articulation. Variations in rhythmic phrasing are EpipE [3] is a uilleann bagpipe chanter interface, which ex- thus an integral aspect of expressive bagpipe performance, tends the capacitive sensing approach to include an array and one of the primary means by which proficient pipers of sixteen small binary touch-switches for each hole. While the Redpipes and EpipE have the capability to mea- Copyright: c 2013 Duncan W. H. Menzies et al. This sure the pressure exerted on the bag by the player’s arm is an open-access article distributed under the terms of the (e.g. using force-sensitive resistors), the authors are not Creative Commons Attribution 3.0 Unported License, which permits unre- 1 http://www.deger.com/ stricted use, distribution, and reproduction in any medium, provided the original 2 http://www.fagerstrom.com/technopipes/ author and source are credited. 3 http://redpipes.eu/ aware of any existing electronic chanter which can be con- nected to a standard set of bagpipes and controlled directly using air pressure. The interface presented in this work achieves this using an air pressure sensor similar to those employed in experimental wind controllers such as the Cy- berWhistle [4] and The Pipe [5]. Figure 1. Close-up of infrared reflectance sensor. 2.2 Technology in the Context of Music Tuition The use and development of technological tools for musi- cal education is an active field of research. A significant proportion of existing work in this area is concerned with piano pedagogy using MIDI input from a digital keyboard, due at least in part to the MIDI protocol providing a simple means of capturing multiple aspects of a performance. One Figure 2. Complete chanter and PCB. such project is the Piano Tutor [6], which combines score- following software and performance evaluation algorithms 3. HARDWARE DEVELOPMENTS with extensive multimedia feedback in order to “create a natural dialogue with the student”. The pianoFORTE sys- 3.1 Physical Construction and Sensing Strategy tem [7] produces visualisations of tempo, articulation and dynamics of a performance in the form of an annotated mu- The purpose of the electronic chanter hardware is to detect sical score. In addressing the development of tools to assist the continuous movements of the player’s fingers quickly in one-to-one instrumental instruction, the authors assert and accurately, and to transmit this data to the host com- that the aim is not to automate the teacher, but to facilitate puter via USB. The interface described in this paper ex- the “difficult communication process” through which the tends a prototype first presented in [13], which employs instructor attempts to describe the subtleties of expressive infrared (IR) LED and photodiode pairs for each hole, be- interpretation beyond simply playing the correct notes. tween which a constant IR beam exists. The player covers The MIDIator [8] program takes MIDI input to allow the the “hole” by interrupting this beam with a finger. user to compare separate renditions of the same piece by This strategy was successful in providing a continuous producing graphs to illustrate variations in tempo, note ve- analogue reading for each hole. However, the physical locity and duration. In addition to MIDI, the SYSSOMO construction of the original chanter led to a somewhat un- system [9] uses raw audio, video and motion data from natural playing experience, primarily as a result of being accelerometer and gyroscope sensors to capture a compre- built using strip-board and through-hole components. The hensive record of a pianist’s movements. A score follow- spacing between the sensors was dictated by practical lay- ing algorithm is employed to align and superimpose two out constraints, and the requirement that the player’s fin- performances with different tempi, enabling direct visual gers sit between the IR emitter and detector prevented the comparison between the playing of instructor and student. board from being housed in a cylindrical shell. While ap- The i-Maestro tool [10] records audio, video and VICON propriate as a tool to investigate the ornament recognition motion capture data of musicians playing bowed string in- concepts that were the focus of the previous work, this in- struments. This information can be played back and dis- terface was deemed unsuitable for use in studying the ex- played in a variety of formats to help the tutor “identify, isting playing technique of piping students in a lesson. illustrate and explain certain issues involved with perfor- One of the primary concerns when developing the im- mance”. The Digital Violin Tutor [11], intended primarily proved hardware was therefore to make the physical play- as a solo practice tool to provide feedback in the absence ing experience as similar as possible to a traditional GHB. of an instructor, employs a transcription algorithm to vi- A custom printed circuit board (PCB) was designed, em- sualise and compare the student’s playing with an existing ploying an integrated IR reflectance sensor for each hole score, or earlier recording made by the teacher. (Figure 1). The distances between the sensors reflect the A study by the Office for Standards in Education (Of- hole spacing of an acoustic chanter. sted) in which inspectors visited 52 schools around the Each sensor is comprised of an IR LED and phototran- UK highlights several ways in which technology can “en- sistor in a single package, both directed upwards. When able attainment”, “enhance progress” and “increase pupils’ an object comes within range of the sensor, the IR radi- motivation” in music classroom contexts [12]. It is again ation from the LED is reflected back and detected by the noted that the tools should not take over the role of teacher, phototransistor.