FIFTY of the territory's top young musical prodigies competed for a chance to join the eminent Asian Youth Orchestra (AYO) at the Hong Kong round of auditions held at the Academy for the Performing Arts recently. The musicians, aged between 15 and 25, were given five minutes to show a panel of music luminaries what they had spent years practising. The AYO, founded in 1987 by publisher Sally Aw Sian and celebrated conductor Sir Yehudi Menuhin, made its debut performance in 1990, playing to rave reviews in Japan, Taiwan, Singapore and Hong Kong. Last year, the 100-member orchestra embarked on a European tour performing at some of the most important concert halls and festivals in Europe. As the AYO aims to expose Asia's brightest young musicians to music-making of the highest calibre, executive director Richard Pontzious was quick to emphasise the high standards on which the auditions were based. ''The principle criteria I use to decide is whether they play well, and then it's the feeling I have as to their ability to spend six weeks with 99 other musicians,'' said Mr Pontzious, who headed the judging panel. Having been to auditions in Korea, Japan and Taiwan, Mr Pontzious was impressed by the high level of playing displayed by the youngsters, particularly the violinists. ''Hong Kong is developing this rich basket of talent. I was particularly struck by the number of male violinists who auditioned, which is very special in Asia.'' Last year, over 1,000 Asian musicians took up the challenge, competing in 14 instruments sections. Numbers were reported to be higher this year. Nicolas Leung Lok, 18, an APA senior diploma violin student who toured Asia and Europe with the AYO for the last two years, had to attend the audition just the same. ''I learned a lot about orchestra technique and playing in a group,'' said Nicolas. First-timer Rina Makino, a Japanese student at Winchester International School, was encouraged by her mother who was deeply impressed by a telecast of an AYO concert she watched in Japan last year. ''The AYO is a big and extremely important event in Japan,'' the 16-year-old said. Mr Dick Kaufman, publicist for the orchestra, believed that ''the AYO reaches out to kids at an impressionable age, an age when they are learning to confront all kinds of educational and social pressures''. The opportunity to meet new friends and explore new cultures proves irresistible to some, like 25-year-old oboe player Damrih Bannawittayakit. ''It's the last year for me to make the AYO,'' lamented the experienced performer, who toured Europe with the ensemble last year. ''It was really good. I got to meet new people and work with top music teachers.''