Kim Changhwan was the producer behind the big names like Shin Seung Hoon,Kim Gun Mo, CLON, he made their biggest hits in 1990s. He was one of the two key words in 90's Korean music industry, the other one was Seo Taeji.

In his recent interview:

Q: When you were producing your own group last year, how did you differentiate them from other idol groups in the market? 
- No matter idol or not, singers only success because of their good music. Shin Seunghoon came out after appearing a few times in radio program,Kim Gun Mo came out because his songs were very unique, Clon, Hong Gyungmin also became famous because of the hit songs they sang. so I think whether idol or not,the music has to be good. 

Q: Is there any idol you covet? 
- I said this on my twitter before, I envy that SM has DBSK, YG has G-Dragon, JYP has Rain. At the moment, I covet YG's G-Dragon the most.

Q: What do you think of the difference between SM, YG and JYP? 
- YG comines DJ,R&B, Electric and house,which are the most popular trends in America right now, kind of remind me of Nicki Minaj. JYP makes new pop music with Park Jinyong's own flavor. SM only makes music that has SM's own color. They collaborate with Swedish composers alot, and also buy European and other foreign songs. 

Q: How do you compare yourself to other producers? 
- To be honest, other companies make similar music. they only change the group that sings the songs, but the music from the same company sounds too similar. I'm different because I dont repeat or recycle the same music, I wrote totally different songs for Kim Gun Mo and Clon. 
We used to have visual singers, they became famous based on their good looks, but the problem nowadays is that there are too many of them....


Source: yes24.com