This is a fendt tractor with engine turned on, then driving at different speeds from an inside perspective. Recorded with zoom h4n at 48 khz, 24bit in stereo. Unprocessed.
I generate a rythmic track,i added at the beginning a sinoid tweeting, then the beat started. At the 6th second, we could notice a silence and after, the speed of the beat decreases.
Constant hum recorded at a jeans factory, with washing machines in the background and a few steam hisses. Recorded at monterrey, mexico with a neumann 82i microphone and zaxcom fusion ii recorder.