The Haas Effect (or Precedence effect) states that a delay of 5–30 ms between two ears causes the brain to perceive direction. However, all-pass filters provide a subtler effect: .
: By repeatedly running audio through all-pass filters, AllPassPhase creates a massive phase shift that spreads out the sound's energy over time. Sound Design
was developed by EnumMusic as an open-source tool for creating phase dispersion. The "Laser" Sound: allpassphase
Can someone explain what an allpass filter does/how it works?
Engineers use allpass sections to create Schroeder reverbs, to emulate analog tape wow, or to linearize the phase response of a crossover network. But misuse it, and you get "phasey" mud—a sound that feels drained of punch even though the meters scream "full level." The Haas Effect (or Precedence effect) states that
In communications engineering, allpass filters are deliberately used to reduce the crest factor of a signal. By rotating the phase of different frequency bins, the peaks that align constructively are dispersed, lowering the peak voltage without affecting the average power—a critical technique in efficient radio transmission.
[ H(s) = \fracs - \omega_0s + \omega_0 ] Sound Design was developed by EnumMusic as an
This is the most common use case. Imagine you have a kick drum and a bass guitar playing the same note. Even if they are perfectly in time on the grid, the waveforms might be out of phase. This causes the low end to cancel out, making your mix sound thin and weak.