Electro-Harmonix HOLY GRAIL MAX Reverb PedalThe Holy Grail Max from Electro Harmonix is a compact reverb pedal that features four different reverb algorithms: Spring, Hall, Plate, and Reverse. The algorithms were designed and tailored for the electric guitar, but work equally well with most instruments and voices. Controls are included for Time and Blend. The Time knob adjusts the reverb's decay when in Spring, Hall, and Plate modes. In Reverse mode, it regulates the length of time between