Tapping on a demonstration, turbine blade at a wind farm. First with knuckle then small stone. It was the size of a bus. Tascam recorder, built-in mics.
Hitting what was either an old lantern or a bug zapper lost in some old woods in various ways (on my palm, knuckle, with a stick, etc) to make different percussion or niche snare noises.
Hitting an old, empty oil drum lost in some old woods in various ways (on my palm, knuckle, with a stick, etc) to make different deep bass noises. Natural reverb since it was in a large open space.
The raw version of this sample was made by hitting my knuckle on a metal sculpture of an aircraft. De-clipped and de-noised just slightly using izotope rx. Verb, eq and comp in logic pro 8 + plugins. Recorded using the spectrumview iphone app. Sample rate = 48ksample size = 24 bit.