Vocal trainer Kim Sung-eun has worked with K-pop artists BTS, TWICE, Kang Daniel, Sunmi, B1A4, After School and Dal Shabet, and is the CEO of an academy established to hone talents. She established WIP Company, a K-pop academy, in 2011 that “aims to become a guide for all people who are running toward their dreams, as well as for the purpose of the Korean Wave to promote Korea,” according to its website. Kim Sung-eun became an exclusive trainer from 2010 to 2015 to agencies like Big Hit Entertainment, Sony Music, C.TWO Entertainment, Music & New Entertainment, K Entertainment and SS Entertainment. She conducted singing lessons with BTS members Jin, Jungkook and V before the group debuted in 2013. "When Jin was an idol trainee at Big Hit Entertainment, he practiced singing Asher Book's 'Try' with me during a lesson, which he could barely pull off back then,” she said, according to the Korea Times. She added, “But after several years, he suddenly sent me his new record of that track with the accompaniment. Then he said, 'Please listen to this. Didn't I improve?' He was so proficient, but what touched me more was his attitude. Despite being a superstar with hectic schedules, he still strives for better." Her bio lists other positions she has held: professor of Practical Music and Vocal Performance, Baekseok Arts University; vocal professor of Practical Music, Dong Seoul University and Taekyeong University; vocal professor of Practical Music, Taekyeong University; professor of Practical Music and Vocalism at Myongji College; professor of Practical Music at Sehan University; and FNC Academy representative instructor. It was girl group Baby Vox Re.V which became her first student and soon after, she was training other singers. She praised TWICE’s leader Jihyo, saying, "She recently played an acoustic gig at a little theater as a part of TWICE's 'Melody project' and successfully live-performed five challenging tracks with all-band sounds. I think she pushed the envelope.” Kang Daniel also impressed her, saying “I was surprised by his vocals after listening to one of his songs without any auto tune. He was a rapper/dancer of now-defunct boy band Wanna One, but his sound was so deep and his ability to interpret music was great. Kang is very serious about his music and puts much effort into his work as well." WIP Company offers vocal, dance and Pilates classes “for anyone who is interested in K-pop culture, from sixth graders to the public.” In training singers, Kim Sung-eun said it “starts from fixing the problems of each student and the upgrading in techniques comes next. But some students feel uneasy during this period, fearing that they are not making improvements in a new way I taught. But they should be more open-minded and embrace the changes instead of sticking to their own belief. If core muscle needed for singing is flexible, it facilitates the learning too." For her, a good singer is someone who “can resonate with the listeners by fluently expressing their emotions in a song while making good use of 'tools' such as tune and lyrics. Hitting high notes is merely a technique. There are numerous singers who can still rock the track with their other merits, without giving out an extremely high-pitched sound."