Itīs difficult to say, the according to the manual, the original is 87dB at 4250 rpm (static noise) and the akrapovic 97dB. At first start after install the akrapovic I scared a little, the sound seemed too loud, but after first ride, I love it. At a closed place, like a garage, itīs appear too loud, but riding the bike itīs great. Well, itīs my opinion! Itīs not boring or tiring, I ride at highway at 60mph, and at this speed I donīt hear the engine sound, the wind sound was louder.