I should probably change that. In this case, a "drop" would be something like a single second of audio.
Instead of saying "Does this single second of audio show up in other songs?" we should ask "Do the frequency components in this song show up in other songs?" (similar ratios of bass, treble, etc.)
What does this mean? I understand 'recipes' here, but what's 'drop' in this context? A continuation of the food metaphor?