User Manual
1. Introduction
© LA Audio 2004
7
1. Introduction
The EQ231G-SP is a high quality dual 31-band 1/3 octave graphic equaliser including
variable Hi and Lo-pass filters, Shelving EQ, Gate and Limiter.
The Graphic Equaliser features centre detented, 45mm faders which give up to 12dB
of cut and boost at 31 ISO centre frequencies, covering the entire audio spectrum (20
to 20KHz).
The Hi-pass filter uses 4th order bi-quadratic topology giving a 24 dB/octave slope with
corner frequency variable from 16 Hz to 160 Hz.
The Lo-pass filter is a 2nd order design (12dB/octave) with the corner frequency
variable from 3KHz to 32KHz.
The Shelving Equaliser faders enable control of the amount of cut or boost, a centre
detent is provided at 0dB. Two rotary potentiometers enable control of the LF and HF
shelf frequency.
A bypass switch allows the whole section to be taken out of circuit.
The Dynamics section uses a fast RMS detector with soft-knee action.
The Limiter has a 3 segment LED gain reduction display.
The Gate has an LED indicator illuminating when the signal is below threshold.
A delayed by-pass relay allows silent on/off switching and also provides direct
throughput when the unit is not powered.
Inputs and outputs are electronically balanced. Each channel has a Peak Indicator
illuminating for an equivalent output signal of +18dBu.
Options
The unit can be augmented by parallel outputs offering a unique transformer distortion
cancellation circuit. This reduces distortion by an order of magnitude compared to
conventional designs and also provides galvanic isolation from connected devices for
the reduction of interference and hum.
