Do pictures speak louder than words ?
These videos demonstrate what locals have had to listen to in the past 3 days . The first clip is the sound of two people driving their cars around and around the track at Ruapuna, this continued all day, the second clip is a very small number of cars which continued all of Sunday until rain intervened. Saturday's noise was the same level as these clips. No doubt your computer sound levels may be set differently than others - this noise was NOT a low buzzing noise , it was LOUD and could easily be heard over 3 km away.
To get a sense of how loud this actually is , you should be able to hear this video clearly from any point in your house.