Ralphi Rosario was a founding member of the influential Chicago DJ group Hot Mix 5. When this group formed in 1981 on radio station WBMX (now WVAZ), Rosario, the youngest member of the group, was still in high school. The Hot Mix 5 went on to become one of the leading forces in the early Chicago house music scene.

Like other members of the group, Rosario eventually branched out into music production and remixing. His first release, made in collaboration with Vince Lawrence, was Sample That! in 1986 under the name Bang Orchestra. In 1987, his collaboration with Xaviera Gold, You Used to Hold Me, became a big hit for Rosario that was subsequently remixed and re-released several times.

Rosario continues to work as a DJ and remixer and has released several full-length albums. He has remixed tracks by artists including INXS, the Shamen, Jomanda, Culture Beat, Gloria Estefan, Deee-Lite, Pet Shop Boys, Madonna, Michael Bublé, Mariah Carey, Ricky Martin, Kelly Clarkson, Pussycat Dolls, and Liza Fox.

On December 1, 2011, it was announced that Rosario, with producing partner Abel Aguilera, received a 2012 Grammy nomination for the Rosabel Club Mix of the Rihanna track Only Girl (In the World).

In 2015, his single featuring Julissa Veloz, La Jungla, gained many positive reviews and rose up Billboard Dance Chart to #5.[2] La Jungla marked Rosario’s sixth Top 10 Club Dance Chart hit as a solo artist

In 2016, his collaboration with Abel Aguilera under their Rosabel alias, garnished Rosario another Billboard Dance Chart #1 single with “Livin’For Your Love” (Your Love). This is his third #1 single with Aguilera under Rosabel and features the vocals of singer Jeanie Tracy on Carrillo Music.

Ralphi has been one of Masterbeat’s exclusive LA resident DJ’s headlining various New Year’s events with partner Abel Aguilera as Rosabel along with spinning solo at other Masterbeat holiday weekend events.