Years ago, I had written some music for a big corporate show. At the show, during rehearsals, they decided one of the percussion sounds I'd used was sticking out too much. Apparently it was drowning out the voiceover.
As the composer, this is not your favorite thing to hear. After weeks of putting this all together, you'd think someone would have thought of this sooner. In their defense, I guess it wasn't obvious until they played it on the 56 whale-sized speakers at the venue.
The producer called me in a panic. I talked him down from the ledge and told him I'd take care of it. I quickly made the changes and posted the track for them, which they downloaded on a laptop and threw into the video just as the show was about to begin. Talk about cutting it close!
Sometimes computers are your friends.