Since the '50s the concept of tremolo has changed very little. Controls for Speed, Depth, Volume, and Waveshape have been the parameters available for adjustment. The Pentavocal tremolo is true to its name - a tremolo with five different voices to choose from. Select the frequency response by turning the rotary selector to the desired setting. From a delicate, shimmery, flutter trem to a pulsy low-end throb they're all there. The Pentavocal trem can certainly also do the classic sound of a vintage valve trem - and so much more. This pedal also has another unique feature - the Bottom control.Velocity - This dial allows you to select the speed of the tremolo. From Super Slow to Super Fast. Depth - Allows you to control the depth of the effected sound (how ironic).Volume - Select from zero output to well above unity gain - this enables you to never be faced with the heinous volume drop that many trem pedals have when they're providing really deep tremming.Bottom - Yes they've labeled one of the controls bottom not out of homage to a British comedy series or to the shapely derrire of the fairer sex, but as a totally new option for tremolo users. The Bottom control allows the user to dial in the amount of mid range and hi frequency cut that occurs as the volume decreases in the trem cycle. Simply put: Turn the bottom control all the way to the left and the volume just increases and decreases as per a normal trem, but set it all the way to the right and you'll find that as the volume decreases all of the hi end and midrange disappears. You can of course dial in as little or as much of this effect as you like. Turning the Bottom control fully clockwise whilst having the depth fully clockwise also allows you to access an asymmetrical wave, which sounds incredibly pretty at high velocity. Lucky old you.Voicing - A five way rotary switch that lets you choose from 5 differently voiced tremolo settings.Tremulate Footswitch - Bring the effect into the signal path by clicking this one. True bypass switching.Wave Footswitch - Allows you to jump from a lovely smooth tremolo over to a hard square chop by simply depressing your foot. Bad foot, ugly, good-for-nothing foot.Power - The Pentavocal trem can be powered from either a nine-volt battery or an external nine-volt adapter (Boss PSA styled is ideal - though anything with a 2.1mm barrel plug with a negative center pin is fine.). This pedal uses some sneaky circuitry to lift the internal voltage up to 17 regulated volts - the benefit of this is far greater headroom.The Tremolo comes finished in vintage pearl with emerald text. An emerald green LED pulses along with the tremolo when the effect is engaged. All components are top notch; Switchcraft jacks, alpha pots, through hole double-sided circuit boards etc. What more could you want?