These two words, wow and flutter, describe the charming warble created by variations in speed on an analog tape recorder. Believe it or not, those are technical terms. You've probably heard the phenomenon, even if you don't know it--it's the way that cassette players (back when people listened to cassette recorders) or old TV episodes slip slightly off pitch.
Whenever there's a technical flaw in audio equipment like this, it inevitably ends up being stretched in two directions. Obviously, when tracking musicians, engineers try to minimize the amount of wow and flutter so that the recording will be accurate. At the same time, the effects aren't always unpleasing, and so musicians often begin incorporating it into the music itself. So in much the same way that distortion from primitive amplifiers became part of the electric blues 'sound,' the pitch inaccuracy of tape-based delay and loop effects has become an effect in its own right. It's popular enough that digital delays like the Line 6 DL-4 or Boss Giga Delay have tape emulation modes, complete with adjustable, artificial wow and flutter (not to mention thousands of guitar snobs insisting that they prefer the real thing).
The LoFi Loop Junky I picked up last month in Portland is not a tape delay at all, but it does, quite intentionally, share a lot of the same sound palette. As the name implies, it's a low-fidelity sampler, with a hard frequency limit of 2.6KHz and a lot of self-noise from the storage mechanism. There are also two knobs for a built-in vibrato, giving it the same kind of pitch waver. I didn't buy the Loop Junky for those wow-and-flutter features, but they're rapidly becoming my favorite reason for using it.
When I first started the pretentious solo project, part of the goal (besides the ability to play music without subordinating my ego to a guitarist's) was to work on songwriting within the constraints of a loop pedal--and those constraints are not inconsiderable. But with that said, the equipment I've used has still been very capable: the DL-4 is not only very high-fidelity, with a long running time and layer-on-layer abilities, but it can also alter playing speed, reverse loops, or play them as one-shot samples. So while structurally it imposes some limits (oh, for an undo function!), sonically and mechanically it's a powerful machine, and it gives users a lot of freedom to explore.
You get none of that with the Loop Junky. It plays loops one way, at one speed, with no automatic stop--and it makes everything you play through it sound a bit like a cheap 8-track, to boot. When I originally heard about the pedal, that didn't matter: its main selling point for me was that it was a boutique pedal with a small footprint, a long recording time, and a battery life measured in centuries. As an occasional open mike player, where setup time is important, the heavy power draw and sheer mass of the DL-4 had become cumbersome. I figured a more agile pedal would be worth some feature set sacrifices.
What I didn't anticipate was the degree to which the Loop Junky, like all Z. Vex pedals, would make up for the loss of flexibility with character. For example, the vibrato is a lot of fun, but it has a kind of low-pass filter on its sound so it's really only audible on mid-range notes, or on chords higher up the fretboard. On low-fret basslines or percussive riffs, the effect is wasted. As a result, with only one layer available, I find myself adapting my approach: instead of looping beats and basslines, it's much more fun to loop the chords and play the rhythm parts by hand. Sometimes this means that a given song just won't work, but the challenge of adapting material to the pedal is markedly different from the Line 6. Instead of simply adapting a song's parts into structural cues, it feels more like creating a new arrangement.
To be honest, it's not surprising that I like the pedal for these reasons. I'm a digital aficionado for recording and production, but when playing out I usually prefer the simplicity and character of analog effects, and I doubt that I'm alone in feeling that way. It's part of what makes the words "wow and flutter" so appropriate--they capture the distortions and flaws that musicians have embraced and incorporated into the genres and forms of their music, not as a burden, but in a sense of joyful play.