Understanding reverb as an instrument of space
Launch library · evergreen read

Reverb simulates the natural reflections of sound within a physical space, giving a recording a genuine sense of size and environment that would otherwise be entirely absent from a dry, completely untreated signal recorded in a small studio room, a sense of place that shapes how a listener experiences everything happening within it.
Producers use reverb quite deliberately as a genuine creative tool, not merely as some technical fix applied at the end, choosing a specific type and amount to suggest anything from a small, intimate room to a vast, cavernous hall, a choice made as carefully as any other decision in the entire mix.
Because it shapes perceived space so directly, reverb functions almost like an additional instrument within a mix, colouring how every other element within the arrangement is ultimately experienced by whoever happens to be listening, an instrument in its own right, even though it produces no notes of its own.