Guitar pedal effect - multi-function reverb. The Fathom is a feature-rich reverb with 4 different customized reverb algorithms to choose from. Easily go from tasteful, small room reverb to long, modulated trails dripping of ambient goodness. The toggle switch adds options for low, medium and high modulation. Use the dampen knob to fine tune the tone of the reverb's decay. The Fathom features 4 different algorithms. Hall - Wide, open and vast with decay that ends with high-frequency rolloff. X knob adjusts pre-delay. Plate - Full Body reverb with a smooth decay. X knob adjusts pre-delay. Lo-fi - Filtered reverb with decay ranging from warm, to thin AM-sounding radio. X knob adjusts filter width. Sonar - Reverb fed with both a high and low octave with the ability to blend the octaves with the X knob.