2 Tito's mid-sized Vodka bottles frozen & then emptied. Put cap back on frozen bottle & let thaw (resulting in about 1/4 of a shot of vodka in each bottle after thawed). While thawing, the resulting audio is natural oscillations coming from the cap of the bottle as the liquid and air heat up, as it thaws... pushing air out of the cap. Squeezed sides of cap on different spots around the rim with 2-5 fingers & applied pressure to the top for other variations in the oscillating sounds. Put a ton of compression/limiter... used izotope rx to get rid of low level room noise and bottle clanking thumps... the zoom h4n had to be at 100% recording volume, so it picked up a lot of breathing & movements of the bottles. Next step: 3 vodka bottles at a time & get recorder closer to the rims of the bottles. Gonna do the next recording on the floor since the recorder picked up tapping sounds from the table when the bottles were slightly moved or the caps were tapped or squeezed harder.