The Joyo R13 XVI Polyphonic Octave Guitar Pedal features controls for mixing Sub Octave Control, Up Octave Control to adjust pitch. Dry control increases the input dry volume. Modulation Control is to unleash the organ tones. The Mod control is the thing you twiddle to get the big room filling organ tones, mixing the octave up and down to create some really fat sounding choir effect. Add a little tremolo, delay or reverb and you have a cool fake organ that will sound like a sweeping synth. Playing around with the Joyo R13 Polyphonic will take your guitar from its clean tone to another dimension, people will wonder where the synth is hidden.