iZotope Stutter Edit ($249 MSRP, $149 until 2/14/11, download; Mac/Win; AU, VST, and RTAS) puts a new spin on stutter and glitch effects by turning them into a performance tool. And because the performance elements are MIDI controlled, you can just as easily sequence them in your DAW.

Stutter Edit is the culmination of a long-term development project by producer and performer Brian Transeau (BT), who has been using incarnations of the software in his performances for years. So you could say it's been extensively BT-tested.

Like any stutter effect, Stutter Edit works on audio passing through it, filling up its audio buffer and then extracting slices for rapid repetition. But that's only the beginning. In addition to manipulating the slice and repeat parameters, you get an array of delay, filter, and distortion effects along with an audio generator that produces noise-based sounds (percussion, whooshes, warbles, and so on), which you can then process through the stutter and effects sections. That makes Stutter Edit a powerful tool for generating sound-effects.

Huma Huma Huma
Stuttering is the centerpiece of this plug-in, and its robust implementation gives you plenty to work with. For one thing, you get an extreme range of stutter rates starting with note divisions from a half-note to a 1024-th note (there are 64 of those in a 16th-note). And all note divisions are offered in dotted and triplet variations. At fast tempos, small note divisions yield rates in the audio range, so the stutters become pitched sounds and the segment of audio being stuttered becomes an evolving waveform. Stutter Edit even goes one better by letting you also choose stutter rates based on pitch. The range here is C2 to C6 (roughly 130Hz to 2kHz).

One of Stutter Edit's more interesting innovations is that the stutter rate is not limited to a single value. You can select as many rates (note divisions and pitches) as you like using the Stutter Matrix section of the control panel (see Fig. 1). These are then arranged on a timeline that you can navigate in many ways. The MIDI Mod Wheel (or any controller of your choosing) overrides any automatic navigation scheme you've set up, letting you traverse the timeline by hand. Automatic navigation can traverse the timeline in either direction with quantized or smooth transitions and with an acceleration curve that you can vary from logarithmic (starts fast, then slows) through linear to exponential (starts slow, then increases). You can also choose from several navigation patterns such as two-steps-forward-one-step back and random. With pitch-based stutter rates, you can use timeline navigation to produce an unending variety of arpeggios (quantized navigation) and glissandi (free navigation).

Fig. 1: The buttons in the Stutter Matrix let you choose stutter rates as tempo-based note divisions or pitches, which produce audio-rate stuttering.

You'll find a handy selection of other stuttering controls. You can separate the left- and right-channels of the sample buffer, using different segments and directions (forward or reverse) of each, and you can choose to navigate the buffer with curve options similar to the timeline's. Navigating the buffer timeline determines where each chunk of audio is grabbed for stuttering (see Fig 2).

You can also animate the gate-length and pan position of the stutters using their own timelines and curves. And much like a step-sequencer, all timeline processes can loop or alternate forward and backward (called Palindrome mode).

Fig. 2: You can set up Stutter Edit's right- and left-channel buffers independently to scan different sections of the buffer at different rates and in different directions. Here the first half of the buffer is scanned forward to extract stutter slices for the left channel, while the second half of the buffer is scanned in reverse to extract stutter slices for the right channel.

The effects modules are standard fare, but they each have timeline-based controls with adjustable curves, just like the stutter modules. Those include independent right- and left-channel delay time, feedback, and amount; filter frequency and resonance; bit-depth and sampling-rate; and dry/wet mix. In short, you can get a lot of stuff moving around (see Fig. 3).

In a nice touch, a resonant combination lowpass-highpass filter at the end of the signal path, whose cutoff frequency is controlled by the MIDI pitch-bend wheel, lets you easily create breakdowns and then snap back to the unfiltered process.

Fig. 3: The top half of the main control panel manages the stuttering, and the bottom half of the panel is where you set up delay, filter, and distortion effects.

A Subtle Gesture
A collection of the aforementioned Stutter or Generator settings mapped to a MIDI note is called a Gesture. You can map Gestures across the full MIDI note range, but you can play only one Gesture of each kind (Stutter and Generator) at a time. When both a Stutter and Generator Gesture are invoked, you can simply mix the Generator's output with the stuttered audio or mix the Generator with the incoming audio to feed the Stutter section.

Stutter Edit's Preset Manager makes it easy to create, edit, and audition Gestures as well as to organize them in banks and arrange the banks in folders on your hard drive (see Fig. 4). You might, for example, create a folder for a gig or DAW project, then create banks for different songs or different DAW tracks. Banks are XML files, which makes it easy to share them.

Fig. 4: Stutter Edit's preset browser lets you select, audition, and rearrange the keyboard-mapped Gestures in a bank. Folders of banks appear on the left, and Gestures appear adjacent to an interactive keyboard graphic on the right. Green dots indicate Stutter Gestures and blue dots indicate Generator Gestures.

Overall, Stutter Edit is an extremely versatile effects plug-in. Its broad feature set makes it applicable across many musical genres—it's not just for glitch music. The combination of Generator and Stutter Gestures is a fascinating sound-design tool. Using Stutter Edit with dual keyboards—one for playing and one for triggering Gestures—opens it up for live performance. And because of its Timeline sliders, you can use its effects modules to create unusual sound processing without any stutters. But, once you start stuttering, it's hard to stop.

Pros: Instant gratification. Excellent factory presets. Useful with mixes, individual tracks, and in live performance. Well worth the time spent getting under the hood.

Cons: None.

Len Sasso is a freelance writer specializing in music technology. For an earful, visit his website, swiftkick.com.