In the case of the "trombone sweetener" from Tribbles, they were an effect recorded in real time with the intention of being sped up to get a unique sound. We had the original real time takes and presented one of them on here as a bonus. If you know the score, it's really wild hearing it at the recorded speed.
Oh! Were those trombones sped up to make the, uh, "mewling kittens" sound that we hear in the score when there are a ton of tribbles in the scene? Not sure how to describe that sound any better.