The E-1231 from Toa Electronics is a single channel, twenty-eight band, 1/3 octave active graphic equalizer with 12dB of boost or cut, designed to allow clean, accurate audio equalization for stage, studio, or commercial applications.
The unit's filters are designed for minimum phase shift and feature smooth slide controls with center detents for easy and accurate adjustment. The filters are summed in parallel for reliability, so that the failure of one filter does not interrupt operation of the others.
In addition, continuously variable high and low pass filters are provided on the front panel. The high-pass filter has a slope of 12dB per octave and is variable from 15Hz to 300Hz, while the low-pass filter can set for either a 6dB per octave slope or a 12dB per octave slope and is variable from 2.5kHz to 30kHz.
An automatic EQ bypass function provides complete equalization bypass in the event of loss of AC power and an output muting function suppresses turn on/turn-off transients. A security cover is included with the E-1231 to guard against accidental disturbance, or intentional tampering when used in fixed installations.