Like all songbirds, Wood Thrushes have a Y-shaped voice box called the syrinx. During his three-part song, a male actually sings pairs of notes simultaneously, which harmonize and blend to produce ringing, ethereal tones.
Wood Thrush - American Bird Conservancy
While the female is not known to sing, the male has a unique song that has three parts. The first subsong component is often inaudible unless the listener is close, and consists of two to six short, low-pitched notes such as bup, bup, bup. The middle part is a loud phrase often written ee-oh-lay, and the third part is a ventriloquial, trill-like phrase of non-harmonic pairs of notes given rapidly and simultaneously.
Each individual bird has its own repertoire based on combinations of variations of the three parts. Songs are often repeated in order. The bup, bup, bup phrase is also sometimes used as a call, which is louder and at a greater frequency when the bird is agitated.[3] The wood thrush also use a tut, tut to signal agitation.[11] The nocturnal flight call is an emphatic buzzing heeh. - Wikipedia
Back when I lived in Virginia, used to hear this bird often.