This paper by Handel, Hartnagel, Sia, and Wolf investigates the connection between coherent and conventional piezoelectric quantum 1/f noise and examines the role of subharmonics in these phenomena. The research explores how piezoelectric coupling in crystalline materials generates two distinct regimes of quantum 1/f noise (coherent and conventional), and demonstrates that subharmonic frequency components play a crucial role in bridging these regimes, with important implications for optimizing noise performance in piezoelectric sensors, resonators, and acoustic devices.