Here’s an example… When I was hired by Ben Burtt to find and record sounds for “The Empire Strikes Back,” I didn’t have a huge amount of experience. I had spent several months recording sound effects in the field for “Apocalypse Now” immediately before Ben hired me, but before “Apocalypse” I had minimal practice collecting sounds. Walter Murch had hired me on that film mainly because of my attitude, not my recording chops. I had never worked on a film before.
 
One of the many new sounds Ben wanted to find/create for “Empire” was the locomotion of the Imperial Walkers, aka “AT-ATs.” They were huge, four-legged vehicles that walked a little like enormous mechanical horses, and like the Trojan Horse, troops were inside.
 
Ben didn’t give me any specific instructions for finding sound elements that might work for the Walkers’ leg movements, except that they had to be “organic,” not electronically synthesized. So, job number one for me was to use my imagination and knowledge of real-world sounds to identify potential candidate sounds.
 
The Walkers look like they’re made of metal. They flex at the “knee,” so there needed to be a “rolling” kind of sound in addition to the impacts when their “joints” locked, and their feet hit the ground. We could have created these sounds in a foley stage, and by pitch shifting and adding reverb we could have made those recordings believable in terms of scale. But Ben and I both thought that a better approach would be to find some kind of very large mechanism out in the world that was already nearly the scale we needed. But what might that be?
 
This was 1980, so there was no internet to rely on. I started brainstorming and making lists of possible things to record. I had a hunch that some kind of factory or industrial plant might have machines that could contribute useful sounds. I started browsing through telephone book “yellow pages,” which were basically phone numbers for businesses of various kinds, and I was looking for key words like “metal,” “foundry,” “forge,” “stamping,” etc. There were quite a few metal-working plants in the general area where I lived that specialized in fabricating, stamping, and cutting large pieces of metal. I started making phone calls.

When you call people out of the blue, asking to come to their workplace and record sounds, you get rejected a lot. But some will be curious enough to say yes. I toured five or six places where I did record some sounds, but none had the “magic bullet” I was looking for. Finally, I found myself in a very large factory that specialized in cutting sheet metal. The machines that cut the metal were called metal shears, and they had a cutting blade a little like a guillotine, but the actions the machine took to feed the metal into the guillotine, cut it, then feed the next piece through made this wonderful multi-syllable sound that I knew immediately could be a great candidate for our Walkers. Part of the process was pneumatic, so you got this air-under-pressure sound that I had never imagined the AT-AT making, but now it seemed so right. Lucky for me and for the movie, Ben loved the sound too, and it’s the main set of elements you hear as the Imperial Walker movement.