This's a Skywalker Sound sound effect. It's created by either Ben Burtt and/or Randy Thom for Star Wars: Episode V - The Empire Strikes Back (1980). It shouldn't be confused with SKYWALKER, EXPLOSION - DISTANT, FAINT EXPLOSIONS 01, which debuted in the aforementioned film, though that may be a modified version of the same sounds. According to Ben Burtt in a recent interview , “The actual weight of the foot, Fwoomp! Fwoomp! Fwoomp! That was an artillery explosion that was recorded in Oklahoma. I went to a shooting range there where they fired at me from five miles away, and they were actual high explosive shells. It was the real thing. ...there’s a target out, maybe two or three hundred yards out in front of me, and we’re in a trench. I put my microphones out there on a long cable, ran it all the way back, and then got down in the trench with this soldier. We were hunkering down and they would fire at us from five miles away. You’d hear the shell coming, you’d hear the distant thump of them firing the shot, and then a moment later there was this — it sounded like a jet plane coming through the sky and that was the artillery shell. It would explode and send shrapnel everywhere, come pinging and zipping around….The pressure goes up in your ears and you feel the vibration. That whoomp! of the 155-millimeter Howitzers was used for the actual step of the feet. It was this nice, heavy, low-end, thump sound.” Links: https://soundeffects.fandom.com/wiki/SKYWALKER,_EXPLOSION_-_AT-AT_STOMP#Audio_Samples