The voice of the theremin is more than just a simple sine wave. Its unique sound is made through two radio frequency oscillators that, when operating at almost identical frequencies, gravitate towards each other. Ultimately, this pull alters the sine wave, creating the signature sound of the theremin. The Theremin Textural Expander (TTE) explores other textures the theremin can produce when its sound is processed and manipulated through a Max/MSP patch and controlled via a MIDI pedalboard. The TTE extends the theremin’s ability, enabling it to produce five distinct new textures beyond the original. It also features a looping system that the performer can use to layer textures created with the traditional theremin sound. Ultimately, this interface introduces a new way to play and experience the theremin; it extends its expressivity, affording a greater range of compositional possibilities and greater flexibility in free improvisation contexts.