How to make the Timbrel of Tension
First, fly to Empchyu and use the Godbird Stone. As you fly around the island, look for the Light World equivalent of the Godbird's Eyrie dungeon. Right next to the dungeon towards the east is a decent sized plateau you can land on, and here'll you will find a Skull Helm. There are clouds that mark the location where you can land.
Open the alchemy pot and mix the Skull Helm with Saint's Ashes, and you'll earn a Sun Crown. Take the Sun Crown and mix it with a Magic Beast Hide and Tough Guy Tattoo, and you'll have the Timbrel of Tension!
Thanks to YangustheLegendaryBandit for the write up on these steps.