Cloud cavitation induces intense underwater radiation noise, with complex spectral characteristics that remain insufficiently understood. This study explores the underlying mechanisms through experiments and simulations on a twisted hydrofoil. Beyond the well-known harmonic tones linked to cavity shedding frequency, two key spectral characteristics were identified: a series of lock-in frequency features and a consistent high-frequency decay rate. Experimental and numerical results reveal that tunnel acoustic modes and hydrofoil structural modes contribute to the lock-in features at their respective natural frequencies, while the collapse of cascaded microscale bubbles drives the regular high-frequency noise decay at a rate of −4 dB/octave. These findings contribute to a deeper understanding of cloud cavitation noise, and provide valuable insights for modifying existing cavitation noise prediction models.