In 1961, the Fender Electric Instrument Manufacturing Company released a complex variation on the tremolo effect known commonly as harmonic vibrato. While not technically vibrato (frequency modulation), this new take on tremolo created an effect vaguely reminiscent of a rotating speaker. Due to it"s complexity and cost, this form of tremolo was short lived, and no adequate substitute existed - until now. Not content to simply duplicate this functionality, ToadWorks USA has created a stereo version of this unique effect that is also capable of standard tremolo effect as well. With the addition of a low-pass frequency trim adjustment and expression pedal control, ToadWorks has taken Tremolo to the next level. The key to the harmonic vibrato is a combination of high and low-pass filters applied to alternating (out or phase) modulated signals. The result is something that cannot be adequately described, it must be heard to be fully appreciated. As with all ToadWorks effect pedals, PipeLine is wired for true-bypass operation.