"We would sing three-part harmonies just for fun, because we shared a room growing up, " Tanya says.

NPR: Charlie Haden Returns To His Bluegrass Roots

The lush, three-part harmonies on their debut CD, Voicings, are the real standout, made even more memorable by carefully crafted, delicate melodies.

NPR: Try Me Bicycle: 'Big Small'

Three countertenors function as narrator, singing in gorgeous overlapping harmonies.

WSJ: John Adams' staged 'Gospel' has NY premiere

Bacharach's lush pop songs from the 1960s and '70s, with their complex harmonies and rhythms, were very different from the three-chord rock 'n' roll tunes that were popular at the time.

NPR: Close To You: Burt Bacharach In Concert