Gestural Interaction of Gamelan Mobile Application: A Preliminary Study Khatriza Ahmad Safan, K.A. Safan Faculty of Computer Science and Information Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia gs57244@student.upm.edu.my Noris Mohd Norowi, N.M. Norowi* Faculty of Computer Science and Information Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia noris@upm.edu.my ABSTRACT Mobile applications have been developed as interfaces for musical purposes. The development of various musical mobile applications comes down to the interactions between users and the applications. Common touchscreen interaction of these applications is unnatural as it loses certain physical aspects such as movement, size, and efort. A preliminary study was conducted to fnd out how users would interact with gamelan mobile applications, as playing on the real instrument and on the applications are diferent. Results showed that even with the touchscreen interaction, users played on the applications using diferent combinations of hands and fn- gers. Factors on users’ familiarity with the playing techniques of the real instrument and the physical aspects of how the instru- ments are played infuenced their interactions on the applications. Findings from this study gave us more information on underlying criteria to design gamelan mobile applications with more natural and expressive features. CCS CONCEPTS · Human-centered computing; · Human computer interac- tion (HCI);· Interaction techniques;· Gestural input; KEYWORDS Music interaction, mobile applications, gamelan, user-study, mobile musical interface ACM Reference Format: Khatriza Ahmad Safan, K.A. Safan and Noris Mohd Norowi, N.M. Norowi*. 2021. Gestural Interaction of Gamelan Mobile Application: A Preliminary Study. In Asian CHI Symposium 2021 (Asian CHI Symposium 2021), May 08–13, 2021, Yokohama, Japan. ACM, New York, NY, USA, 3 pages. https: //doi.org/10.1145/3429360.3468199 1 INTRODUCTION As mobile devices become ‘smarter’ and more ubiquitous, smart- phones and tablets have also been utilized as musical tools. Due to its powerful computational ability, with a rich suite of onboard sensors, network capabilities, easy to program, and above all ubiq- uitous, mobile phones are uniquely positioned to have a widespread Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for proft or commercial advantage and that copies bear this notice and the full citation on the frst page. Copyrights for third-party components of this work must be honored. For all other uses, contact the owner/author(s). Asian CHI Symposium 2021, May 08–13, 2021, Yokohama, Japan © 2021 Copyright held by the owner/author(s). ACM ISBN 978-1-4503-8203-8/21/05. https://doi.org/10.1145/3429360.3468199 on cultural impact on how people make and share music [1]. Vari- ous mobile technologies such as accelerometer, gyroscope, camera, built-in microphone, speaker, touchscreen display, and others, have enabled them to be utilized and adapted as musical interfaces. Mo- bile applications for musical purposes have provided an alternative for desktop-based music software, especially with virtual mobile instruments as well as music production applications. In addition, there are also mobile interfaces that are designed to allow for ex- pressive music interactions namely the Smule’s Ocarina [2], tangible WhammyPhone [3], augmented mobile instruments [4], as well as collaborative mobile music performances such as Stanford Univer- sity’s Mobile Phone Orchestra (MoPho) [5]. 2 MOBILE MUSIC INTERACTION Common interaction with mobile applications is the touchscreen, where this interaction is also used in music mobile applications. Gestures such as swipe, tap, touch, pinch, multitouch, and zoom are interchangeably used in most mobile instruments and music production applications. Mobile music applications are often ofered as touchscreen-simplifed versions of traditional interfaces, where musically trained users will already understand how to control these interfaces [6]. These include mobile applications designed based on traditional musical instruments, such as the gamelan. The gamelan is a percussion ensemble that originates from Indonesia. It includes several diferent instruments made from iron, bronze, and wood. The instruments are played by striking on their surface using mallets. Playing these instruments on mobile applications requires the users to use their fngers instead of mallets. Due to the diferent ways of interaction, a study was conducted to fnd out more about users’ gestural interaction with gamelan mobile applications. 3 EXPERIMENT A preliminary study was conducted to explore users’ gestures and afordances on mobile applications based on a gamelan instrument, the bonang. 12 participants (4 males and 8 females) were involved in the experiment where three categories of users were identifed: the novices, the amateurs, and the experts. The novices consist of frst-year music students at a local university. The amateurs are fnal year music students and a lecturer who have taken gamelan lessons and have some performance experiences. The experts are gamelan educators who possess tertiary qualifcations in gamelan and Malay traditional music who are also established, gamelan performers. The study was conducted in a remote setting via online interview, due to the restricted movement order of the Covid-19 pandemic. 146