。
I heard a tree fall with a terrible crash.
Literal
Tree [subject-が] terrible sound [object-を] make-[and-て] fall [nominalizer-の] [subject-が] was-heard.
A parallel rendering of the same kind of scene with すさまじい ('terrible, fearful, tremendous') replacing the mimetic どすんと. The shift from a mimetic to an i-adjective modifying 音 changes register: mimetics are more vivid and casual, i-adjective descriptions more narrative and controlled. Same skeleton, different flavour.