YPAO

YPAO, or Yamaha Parametric Acoustic Optimizer, is a room calibration system developed by Yamaha for its AV receivers and home theater components. The system uses a calibrated microphone to measure the acoustic response of a room and the positions of connected speakers, and then computes adjustments to optimize sound at the listener’s position. YPAO can automatically set speaker levels, delays, crossover frequencies, and equalization to compensate for room effects.

The core feature is parametric equalization and time alignment across channels, aiming to flatten the overall frequency response and improve imaging. A variant called YPAO-R.S.C. (Reflected Sound Control) adds processing intended to mitigate the impact of early reflections by modifying the signal path in relation to room reflections. The calibration is typically performed via a test sequence using a measurement microphone, generating data such as frequency response, impulse response, and room mode information.

Usage and outcomes: Most Yamaha receivers provide feedback on recommended settings and allow manual adjustments; users may place the microphone at the main listening position or at multiple positions to tailor the setup. YPAO is one among several room-correction systems in consumer AV gear, and is commonly discussed alongside competing approaches such as Audyssey MultEQ and MCACC. The system does not permanently alter the room but compensates the speaker output through the AVR’s processing to improve sound at the listening position.