Once on stage, now behind scenes: Kim Su-bin blends idol insight with songwriting craft

Korea Herald

15-05-2025

With over 400 songs to his name, Kim says understanding each idol's voice and story is key to great K-pop
When Kim Su-bin debuted in 2013 as a member of the K-pop boy band Say Yes, he was 27 — an unusually late age in an industry built on youth.
'Most idols debut in their teens or early 20s and I was considered too old,' Kim said during an interview with The Korea Herald on May 8. 'So I signed a five-year contract instead of the usual seven.'
Now 38, Kim has transitioned from idol to full-time songwriter and producer. He has written more than 400 songs across K-pop, J-pop and C-pop — credits that include Super Junior's 'Super,' Exo-CBX's 'Gentleman' and Twice's recent track 'Dive.'
But long before he took the stage, he was producing behind the scenes.
'I was already writing songs in 2008,' Kim said. 'Back then, collaboration between songwriters wasn't common in Korea. Usually it was just one or two people. I did both producing and toplining on my own and recorded demos in my own voice.'
One of those demos landed on the desk of Kim Chang-rak, then-CEO of Music Factory, who offered Kim the opportunity to debut in a band.
'I thought it was an interesting proposal,' he said. 'So I started training and after about two years, I debuted with Say Yes.'
His time as an idol, Kim says, taught him far more than how to perform — it reshaped the way he writes music today.
'I learned how singers manage their vocal positioning, how they sing while dancing, how diction varies depending on mouth shape,' he said. 'Before I became a singer, I had trouble writing songs for others. I didn't know how to accommodate those differences. But now I understand which melodies are right for which voice, and what makes a song easier to perform. That insight helps determine whether something becomes a title track or not.'
Understanding idols as individuals is just as important as understanding their voices, which Kim says is something most producers overlook.
'A lot of songwriters don't even know the members' names,' he said. 'But I was an idol, so I studied other groups a lot. If another idol did something cool on stage or had a unique singing style, I'd keep that in mind. The skills I picked up back then help me today, especially when directing vocals. I know what makes the artist more comfortable and how to bring out their best.'
Kim has also watched the way K-pop songwriting has changed, especially as the industry has gone global.
'In the early 2010s, Korean producers usually worked solo,' he said. 'Maybe we'd hire a guide vocalist, but collaboration wasn't part of the culture. Around the mid-2010s, that started to change. More global collaborations happened — entertainment companies, publishers, song camps, sessions. It became a system.'
These days, song creation is a structured, collaborative process. There's the producer, who creates the instrumental base; the topliner, who writes the vocal melody; and the lyricist, who provides the lyrics. Sometimes the lyricist is the topliner, sometimes not.
'Mixing is like cooking, (it's) combining ingredients to make a delicious dish,' Kim explained. 'Mastering is like inflating that dish so it's louder and more impactful. Damping gives the track more punch and clarity.'
While some songs are created in one-on-one settings, K-pop's competitive ecosystem often means producers distribute tracks to multiple collaborators globally.
'Sometimes the company or publisher sends a track to top musicians in several countries. Sometimes it's sent to close topliners directly,' Kim said. 'On average, about five people work on one track, usually more topliners than producers, and most of the time, topliners also write the lyrics.'
Because idol groups often have multiple members, variety in vocal tone is key, which is why working with different topliners can elevate a song.
'We work from a shared reference point. It could be a musical color, a universe building concept, a lyrical theme, even the fandom's name,' he said. 'The lead producer ensures everyone stays in the same lane. Usually, whoever has the most experience takes that role.'
So, what's trending in K-pop right now?
Kim points to a return of early-2000s sounds.
'People are getting tired of overly digitalized music,' he said. 'There are a lot of new groups embracing 2000s-style production. The girl group Kiss of Life is a good example.'
One song that stood out to him was the group member Natty's solo song 'Sugarcoat,' released in 2023.
'I was shocked when I heard it,' he said. 'It's the kind of music I grew up listening to. The trend has come full circle. I think what's popular now is expressing old-school sound in a Gen Z way.'
Today, Aiming Music, the label Kim founded seven years ago, works with 17 songwriters, including many from outside Korea. And he's recently noticed something new: more American producers are showing interest in K-pop.
'Ten years ago, most international songwriters we worked with were from Sweden,' Kim said. 'These days, it changes daily. There's still a lot of activity from Sweden, Denmark, Finland, the Netherlands and New Zealand. Even Germany and the UK. But since last year, there's been a clear uptick in interest from the US.'
The reason? More K-pop groups are touring the US, and the economics still make sense.
'It used to be hard to connect with American songwriters,' he said. 'But now that more idols tour the US, there's more interest. And in Korea, physical albums are still printed, so writers can earn from CD printing, unlike the US or Europe, where streaming dominates and physical sales are rare. That might be another reason.'
In this series, The Korea Herald sits down with some of the key behind-the-scenes creatives in K-pop — the producers and songwriters shaping the sound of a global phenomenon — to hear their stories, trace their career paths and explore their insights into the industry's evolving trends. -- Ed.