they were in the 80's also(lawn chairs??) The first(major)show I remember seeing was DCI North at Pontiac Stadium(a dome stadium was no place for a Drum Corp show)back in 76(?).
The 70's were probably the premier decade for Drum Corp before "mickey mouse" and "broadway" took over.
It all started to go down hill when they removed the American Flag guard unit from the regulations. I think I'll post a thread in chat, we are way off topic here.