Police seized sound equipment during a rave believed to have been attended by up to 200 people at a forest in Suffolk.
The force helicopter was scrambled and officers sent to block off routes into Rendlesham Forest overnight on Friday.
They also liaised with people at the site to bring the event to a close.
When this failed to stop the noise, which had prompted complaints from nearby residents, police seized the equipment at 0400 BST.
There is an ongoing investigation into the incident, a police spokeswoman said.
An officer on patrol was alerted to the event after coming across youths who said they were going to a party at the forest.