You can have fireworks go off such that the light from the next one reaches the crowd at the same time as the sound from the first. Tempo can be adjusted by cha

You can have fireworks go off such that the light from the next one reaches the crowd at the same time as the sound from the first. Tempo can be adjusted by changing the location/altitude where they go off. Then you only notice something off when you transition between fireworks that sound different, and even that can be mitigated by having transitions where one of the old type goes off simultaneously with one of the new type. You can't really adjust it on the fly, but you can break the show into discrete blocks that are synced to pre-recorded music, for example each song, and trigger each block on a cue to make what looks like a smooth continuous show.