All Pass Filter

Purpose

Although the All Pass Filter produces a flat amplitude response, it produces a smoothly changing phase response. A -360 degree phase shift is imparted to frequency components above the Center Frequency setting. The All Pass Filter may find applications in custom crossovers to help with driver alignment and in some types of special effects processing.

Controls

Q-Factor

Controls the abruptness of the phase shift produced by the filter. Higher settings produce a more abrupt phase shift at the Center Frequency.

Frequency

Sets the frequency about which the phase shift is centered. The phase shift is exactly -180 degrees at the center frequency.

Graph... (Graphical Frequency Response)

Displays the frequency response of the filter. See the EQ Curve Graphics Display documentation for a complete description.

Phase Response

The phase response of the All Pass device for a Center Frequency setting of 1000Hz and a Q-Factor of 1/sqrt(2) or 0.707.