Right
啇 supplies the sound (standalone dí, drifting to dī here).
啇 is rare on its own but appears as the phonetic in a productive family:
摘 (zhāi, pluck),
嫡 (dí, legitimate heir),
敌 (dí, enemy),
适 (shì, suitable). The shared rime is the giveaway. Faint semantic echo too -
啇 contains
口, hinting at the small drop-shape that falls from above.