Also can be found as part of the Blue Cat Freeware Plugin Pack
Blue Cat’s Triple EQ is a 3 bands semi-parametric equalizer that can be controlled as a single filter with customizable shape. It includes a low shelf filter, a high shelf filter and a boost/cut peak filter. Its wide range of gain (+/-40 dB per band) and bandwidth (.01 to 5 Octave) makes it very versatile to create any filter shape. The three filters are linked together so that when you change the center frequency or the bandwidth, the parameters of the three filters are modified accordingly: you can control the entire equalizer characteristics with a single mouse click.