There is a growing number of made-in-Singapore luxury In-Ear Monitors in the audiophile market. These IEMs are usually limited in stock and cost thousands of dollars. The Sound Zone checks out cult brand Subtonic, and the team behind the sold-out Subtonic Opus Reference Monitor, or STORM which cost S$7,000 a pair. In this exclusive interview, co-founders Ken Liu and Cornelius Lee share about their labour of love and how it all began.