Complex sentence: Rope tension snare and bass drums are tightened by the use of tugs or ears that apply pressure to the rope, that pressure is transferred to the heads when the rope compresses the counter hoops causing them to move slightly closer together.
Split into simpler sentences: Rope tension snare and bass drums are tightened using tugs or ears that apply pressure to the rope. That pressure is transferred to the heads when the rope compresses the counter hoops causing them to move slightly closer together.