In FL Studio’s — a powerful 6-operator FM synthesizer — the “reverb” isn’t a separate send effect like in a mixer. Instead, it’s built directly into the Synthesis > Main tab, as part of the Effects section alongside a delay, chorus, and filter.
The IR Section allows you to customize the reverb's impulse response:
Sets the time before the first reflections are heard, helping to separate the dry "attack" from the reverb wash.
Sytrus Reverb is a powerful and versatile reverb plugin that's capable of producing a wide range of spatial effects. By understanding the interface and experimenting with the various controls, you can create stunning reverbs that enhance your tracks. Happy mixing!