The Precedence Effect and Haas Effect describe the same psychoacoustic phenomenon from different research perspectives. Lothar Cremer and later Helmut Haas studied how humans perceive paired sound sources with small time delays. The core finding is consistent: the first arrival determines perceived direction. The effect operates within a specific time window that depends on the signal type. For clicks and transients, the fusion window is approximately 5 ms. For speech, it extends to 25-35 ms. For music, it can reach 40-50 ms, particularly for sustained tones. Outside these windows, the delayed sound is perceived as a distinct echo. Within the fusion window, the delayed sound is not simply ignored. It contributes to perceived loudness (summing effect), spaciousness (envelopment), and tonal coloring. This is why a delayed speaker can add 6-10 dB of level at a listener position while the listener still perceives the sound as coming from the earlier source. The effect has limitations. If the delayed sound is more than approximately 10 dB louder than the first arrival, it can override the precedence effect, pulling localization toward the louder source. System designers must balance level and timing to stay within the effect's operating range. In practice, every distributed sound system relies on the Precedence Effect. Main speakers establish the directional anchor. Delay speakers, timed to arrive 5-15 ms after the main sound reaches each zone, add local level and clarity without disrupting the perceived source direction. SonaVyx's transfer function and impulse response tools measure the actual arrival times needed to set these delays correctly.