Tap Internal starts with Duncan's beloved shortwave radio sounds, which quickly evolve into a harmonic buzzing with rich metallic overtones, punctuated with occasional slow descending electronic swoops, similar to the power chords in the final section of Karlheinz Stockhausen's Hymnen. A sudden change takes listeners to a looped and echoed abrasive section, sometimes sounding like a hydraulic engine and sometimes like the loop at the end of an old vinyl record. There is another sudden transition to a low-frequency rumble with wispy high overtones, then a brief interlude of loud power electronics, followed by a long, slowly evolving drone that occupies nearly two-thirds of the piece. The final drones start from the power electronics, but at a lower volume, and slowly evolve into a high-pitched shortwave sound that continues for over ten minutes, slowly waning into silence. From the silence there slowly arises another rich harmonic drone, reminiscent of the opening section, which comes to a sudden stop at the end of the piece. Duncan's pieces have generally tended to relatively static sections, with sudden transitions between them. This piece has its share of this kind of material, but the last half of this piece shows an evolution that is unusual in Duncan's work. After the loud, harsh sections of abrasive loops and power electronics, the listener's ears are cleansed, and one can pay attention to the detail and tranquillity that comes after. Tap Internal is one of Duncan's best pieces, displaying a greater variety of timbre and volume, as well as a unity of purpose, than many of his earlier pieces. The long drone sections and relatively few harsh sections make this a suitable candidate for newcomers to Duncan's sound world.
AllMusic Review by Caleb Deupree