Koay Loong Chuen (better known as Jellal Koay, b. 2001) is a Malaysian composer whose works mainly attempt to craft multifaceted experiences through complexity. Interested in the potential of creating paradoxical states by challenging the limits of conscious perception, his current musical pursuits explore the possibilities of subconscious perception in music by overloading perception through the complicated interweaving of musical information. Jellal’s works have been showcased in various countries including Malaysia, Singapore, Italy, Germany, Japan, Australia, and the United States.

Jellal’s musical journey began in 2012 when he started piano lessons with Ms. Kwan Yin Hui. His passion for music quickly flourished, and he became the choral accompanist for SMK Seri Kembangan in 2015-2019, where the choir earned prestigious accolades, including awards at the Malaysian International Choral Festival in 2015 and the Malaysian Choral Eisteddfod National Competition in 2017. As a pianist, he has been recognized with a merit award in the final round of the Southeast Asia International Piano Competition in 2020.

He has won several prizes as a composer, including the 1st Prize for Solo Harmonica & Orchestra category in the Hong Kong International Composition Competition for Chromatic Harmonica 2021, 2nd Prize for Brass Trio category at The Diversity Initiative Call for Scores, and he was selected to be featured in the Gilgamesh Music Festival 2025 and Malaysian Patriotic Music Composition Competition 2019 (Choir Category).

Jellal has worked with various ensembles and artists, including Ensemble Spectra (BE), Ensemble Musikfabrik (DE), Les Éclats du Son (DE), b-l duo (SG), Pan Pacific Woodwind Quintet (US), Ensemble Virama (MY), Nina Janßen-Deinzer (DE), Michelle Hromin (HR/UK), Carolin Ralser (IT/SG), Christoph Wichert (AT/SG), Martin Jaggi (CH/SG), Scarlet Gouk (MY/HK), and others.​