There are several specific technical issues at work here. The first is the setting of the EDP, with quantize=on and Insertmode=Insert. Quantize is a state of operation in the EDP in which different types of functions (Insert, Multiply, etc.) happen specifically at the beginning of new cycles. Quantize is therefore an excellent setting for highly rhythmic looping approaches, particularly in cases such as this one, where the EDP is following an external clock.

The second key idea here is the use of Insert, a very powerful and flexibe EDP function. For the purpose of this solo, Insertmode=Insert, which means that it can add new material to an existing loop in increments of new cycles which are added onto previous ones. This might look confusing on paper, but it should make more sense when you hear the function in action.

The third noteworthy technical element to this solo involves the use of a feature called "Loop Windowing," which I first stumbled across by accident with David Torn back in March of 1998. The basic idea of Windowing begins with taking a loop of several cycles in length, and then "remultiplying" it down to a smaller number of cycles. By its very nature, this has the result of eliminating part of the loop, because when you reduce the number of cycles in a loop, you're losing the content of the cycles you're eliminating. (Again, this is a technique which makes more sense heard than read).

The interesting thing here is that when you hit the undo button after remultiplying down to a smaller number of cycles, you can actually scroll through different sections of the loop in the cycles which were lost. So even though they're no longer in the basic loop you get following remultiply, they're still contained in the EDP memory, and can be "scrolled through" by hitting undo. Pressing the undo button at different times can dictate where one section of memory ends and another begins, hence the concept of "windowing."

Funnily enough, this feature was technically a software bug, but I (and the other users who had discovered this feature on their own, independently of myself and David) asked that it remain intact in future software upgrades! (It has survived, and in fact been expanded upon, in the LoopIV upgrade.)

Because of its fairly basic structure, and the way different functions were used, this solo makes a good opportunity to pinpoint specific EDP functions. The following is a function-by-function transcription of the solo:

:00 to :02 - the initial cycle (which is equal to one quarter note at 180 BPM, the tempo of the song) is recorded.

:02 to :03 - a second cycle is added using Insert, with a new phrase being played while Insert is active, after the first cycle. The Insert button is pressed twice here: once right before the new cycle, and a second time during the recording of the new cycle, to close the Insert function.

:03 to :09 - the basic loop (which is now two cycles long, due to the second cycle being inserted) is multiplied out to a length of four cycles (or one measure). This isn't immediately audible until...

:09 to :59 - You can hear the newer, longer cycle length, by virtue of the new phrases which are gradually overdubbed onto the loop, giving it a much denser and more complex sound.

:59 to 1:09 - The loop is reversed.

1:09 - The loop is back to normal direction, but is re-multiplied back down to two cycles; you can hear this by virtue of the loop repeating after every two quarter notes.

1:15 - Loop Windowing is in effect, by hitting the undo button to scroll through different memory sections of older parts of the loop which have been erased from normal playback, due to remultiplying the loop down to a smaller number of cycles.

1:20 - the loop has been remultiplied again, back down to a single cycle (of one quarter note in duration). Between 1:20 and the end of the solo, you can hear the single-cycle texture of the loop change at certain key points; again, this is the sound of Loop Windowing being engaged by each successive hit of the undo button. In effect, the solo itself loops structurally: compare the very ending to the very beginning.

This particular Insert setting has the result of completely erasing any existing sound in the loop, replacing it with whatever is being played through the EDP at the exact time that the insert button is being depressed, and then instantly cutting back to the original sound once the button is released. It's the same basic principle as "punching in" in a multitrack studio scenario. Because this is being done with quantize=off, some of these "insertions" can be of an extremely short duration -- no longer than a very quick tap of the button (a handful of milliseconds), potentially.

There are a large number of EDP "replacements" (so to speak) in this particular loop, and probably some reversing going on as well (it's often hard to remember exactly what EDP functions were used in order to produce a final loop). One review of Disruption Theory assumed that this bit was an analog synthesizer being triggered by a MIDI guitar, and while that's not the case, I certainly take that observation as a compliment.

After it was recorded, the backing loop was fed through a filter, which was opened up and then closed througout the length of the loop. (Interesting note: at the very beginning of this piece, the filter was set to such a low frequency that the "clicking" noise you first hear is actually the audible sound of cycles per second!)

The initial sound which opens the remix is an EDP loop fed through the Quadraverb, for the syncopated 8th-note effect. But my favorite EDP moment in this remix enters at :47; this loop was played using an Ebow fed through the EDP using unquantized Insertmode=Replace for a very fragmented, glitchy sound. It's an eight-bar loop, which repeats three times and then reverses itself in the middle of bar six.

Another EDP loop, this one more transparent and almost ethereal sounding, appears at 1:33; I know this one was reversed, and it's probably Ebowed. (You can hear it more clearly at 2:55, where it re-enters the arrangement.) At 5:05, you can hear a pulsating, keyboard-esque EDP loop fade into the picture; this is the same loop from the coda example above, and is the only sonic element from the original version of the track which appears in this remix.

Whereas loops with a high feedback level often build up to a very dense wall of constantly repeated sounds, setting the feedback to one repetition, as is the case here, means that you have to keep playing in order to sustain a constant sound. It also means that, unless you keep playing the same thing into the EDP, the texture constantly changes and evolves, and does so quite quickly. The sound of this solo is kind of interesting, then, because it's a non-repetitive loop played on an Ebow, which leads to a series of double-stops (muso-speak for two notes being played at the same time.)

A couple of chunks of this solo were chopped out after the fact to make it more to-the-point, but the bulk of the live improv is intact.

The vaguely Hendrixy loop which enters at 1:06 is another EDP specimin, which was clearly reversed at some point. (The same loop is used as a one-bar fill at a few key transition points in the album version of the tune). At 1:50 you can hear a filtered version of a pulsating guitar loop, which appears in more extended fashion in the "Grid" mix of the same track.

The mystery loop in question really kicks in around 1:57 (you can hear this same loop in a modified form in the "Mobius" remix of the same tune). A higher bit comes in at 2:14; sounds like a Whammy pedal to me, and you can also hear it very clearly in the "Mobius" mix, especially at the end.