The Equalux from Tonelux is a discrete, dual 4-band parametric equalizer housed in a 19", 1U rack enclosure. There are no dedicated Q controls on the front panel, but rather the filter width is internally adjusted based on the boost and cut settings using a "Constant Energy Curve." Also known as "Proportional Q," the circuitry keeps the bandwidth wider at lower boost/cut levels, and becomes narrow at higher boost/cut levels, in the process delivering a musically pleasing result.
 
With four bands of controls, each of the lower two have slightly different frequencies, allowing the lower band to go to 18 Hz, while the upper two bands are identical.
 
The "In" button is a silent in/out button that does not bypass the unit, but bypasses the filters and when in, the button pulsates showing signal presence. This can be selected internally, to read the signal at the EQ input, or post EQ at the output.
 
The rear panel houses an input XLR with a nominal level of +4 dBu and a 1/4" jack that has a -6 dB pad for a nominal input level of +10 dBu. The output is an XLR with a nominal level of +4 dBu.