How long is a duration unit actually last in DeHackEd

Im trying to make a song that last about just as long as a frame of the super shotgun. But the duration thing is making it difficult. I was wonder, how long is each duration last. Does a 1 duration last one second (i doubt), 1/10th of a second or wut? Can some one give me a idea? :)

I'm pretty sure the dehacked durations are 1/35 of a second. So most of the durations are actually pretty damn short.

Doom is meant to run at 35 fps, which I guess is where the duration comes from.