Underneath the envelope knobs are the green Freq. knobs, which control the frequency of the sound. START is the start frequency, and MIN is the minimum frequency. SLIDE makes the sound change frequency over time, with a positive number making it go up, and a negative number making it go down. D.SLI., or Delta slide, affects how fast the frequency changes. Values closer to 1 or -1 make the frequency change faster, while values closer to 0 make it slower. A negative value reverses the slide, making an upwards slide go downwards and vice versa. V.DEP., or vibrato depth, changes how much of an effect vibrato has, while V.SPD., or vibrato speed, changes how fast the vibrato is.