Aftre the success of "Rapper's Delight", Hip Hop was no longer considered illegal or inapproriate but it was starting to be accepted by the mainstream. Consequently, the industry also wanted to cut a slice off this new business branch. Many dance films started to portray an all -singing and all-dancing romance and live shows in colourful costumes and party atmospheres did not represent the original culture. 

The new school was initially characterized in form by drum machines led by minimalism, often tinged with elements of rock and punk music. It was notable for rap being delivered in an aggressive, self-assertive style.
These elements contrasted sharply with the funk and disco influenced outfits, novelty hits, live bands, synthesizers and party rhymes of artists prevalent in 1984, and rendered them old school. Hip Hop History

The rappers of the new school age who desired to preserve their cultural heritage turned to a "consciously hardcore", "a reaction against the populist trend in hip hop at the time", and "an explosive emergence of an underground alternative".

RUN-D.M.C. on their track "My Adidas"

 

"We took the beat from the street and put it on TV."

Darryl McDaniels:

 

"[T]hat's exactly what we did. We didn't really think it was pioneering, we just did what rappers did before us was doing on tapes. When a lot of the old guys, like Kool Moe Dee, The Treacherous Three, and Grandmaster Flash, got in the studio, they never put their greatness on records. Me and Run and Jay would listen ... and we'd say, 'They didn't do that shit last night in the Bronx!' ... So we said that we weren't going to be fake. We ain't gonna wear no costumes. We're gonna keep it real."


Artists RUN-D.M.C.

LL COOL J