Room EQ Wizard (REW) is a free software for optimizing room acoustics and audio systems. It offers comprehensive features for measuring and analyzing room acoustics, loudspeakers, and audio devices. Key functionalities include generating audio test signals, measuring SPL, impedance, frequency and impulse responses, distortion, and reverberation times. REW also provides detailed analysis through phase, group delay, spectral decay plots, waterfalls, and real-time analyzer (RTA) plots. It can calculate Thiele-Small parameters, analyze modal resonances, and adjust equalizer settings to enhance acoustic performance.