ABSTRACT
Phase, in sound theory at least, describes the time relationship between two or more sine waves of the same frequency. Phase is measured in degrees. The degree of phase shift is dependent on the time gap between the two sine waves, but also on their frequency. For the same time gap, different frequencies will have different phase shifts. Phase problems occur when people sum similar waveforms that are either phase-shifted or phase-inverted. If the time gap involved is smaller than 35 ms, one should expect comb filtering and its subsequent tonal alterations and timbre coloration. Phase problems are not always audibly obvious. Phase checks and corrections are better carried out before mixing onset. The Haas trick was not invented by Helmut Haas, but it is essentially a demonstration of the Haas effect. Haas was interested in what happens when an initial sound is quickly succeeded by similar sounds from various directions.
