Serato's acclaimed Pitch ’n Time AudioSuite non-real-time plug-in has been around for a few years. As expected, version 2.0.1 ($799) offers additional features such as multipoint control and the ability to process 48 tracks simultaneously. Pitch ’n Time works with Mac and Windows versions of Pro Tools 4.0 and higher.
A product such as Pitch ’n Time is commonly evaluated on the quality of the technology and the user interface. Pitch ’n Time rated well in both departments, though the sonic-quality results varied depending on the material I processed.
The user interface is divided into three sections: Tempo, Pitch, and Length. The Tempo section offers three time-stretch modes. Fixed mode is the simplest and lets you specify temporal changes in terms of bpm, ratio, or percentage. The ratio fields provide an easy way to change tempo when translating from one frame rate to another. The bars and beats field also calculates the tempo of the selected passage. You can set the preferences to display units in terms of samples; hours, minutes, seconds, and milliseconds; SMPTE time code; or feet, frames, and subframes.
Variable mode controls the rate at which tempo changes occur and is useful for making gradual changes in tempo. The panel provides a graph of the selected waveform, letting you grab the handles on the display's horizontal line to ramp the tempo up or down over time. Mouse clicks add more movable points in the ramp, so you can adjust the tempo throughout a musical passage. The continuously variable zoom controls for each axis are a nice feature that I'd like to see added to other applications.
Morph mode lets you create instantaneous tempo changes. For example, you can lengthen or shorten a single note within a passage. The Morph panel contains two waveform displays: Source and Guide. The Source graph shows the waveform that you want to process and allows you to place markers delineating the desired transition points. You adjust the markers in the Guide graph. An outline of the new waveform is superimposed over the guide waveform's image. You can also load a guide waveform as a visual reference when matching different segments to one another.
Pitch ’n Time's Pitch section includes three pitch-shifting modes. Fixed Pitch-Shift mode has simple controls for making global pitch changes according to key, percentage, or semitones and cents. The Variable Pitch-Shift mode works in the same way as the Variable Time-Stretch mode: it lets you create changes in pitch over time. The third mode, Varispeed, behaves like analog tape by changing pitch and tempo in tandem.
The final section, Length, has only one mode. It shows the start, end, and length of a selection, before and after processing.
Pitch ’n Situation
I tested Pitch ’n Time on a variety of production tasks. In general, I found the audio quality good; however, the further you are from the original tempo, the more artifacts you hear. The artifacts have a grainy quality with a digital edge reminiscent of flanging. Discerning ears will notice a difference at any setting, but artifacts become more obvious at a deviation of about 10 percent.
The problems were most noticeable when I processed standalone tracks, such as a 24-second narration I shortened to 20 seconds and lengthened to 28 seconds. Other source material — including percussion, guitar, bass, and even full mixes — was more charitable to Pitch ’n Time in terms of range; the changes became questionable at around 20 percent. Generally, increases in tempo and pitch seemed to be more forgiving than decreases.
I also tested Pitch ’n Time's Capture feature, which allows you to capture the tempo of one passage and stretch another passage to match it. That easy-to-use feature worked better in Pitch ’n Time than on some dedicated slice-and-dice looping packages.
Pitch ’n Time is impressive. The graphs are useful, and the ability to specify morph points provides creative options beyond simple global tempo and pitch changes.
The audio quality is as good as anything I've heard, though artifacts can occur depending on the degree of change and the source material you process. Nevertheless, those problems reflect the state of the technology rather than the product itself. Overall, Pitch ’n Time is an excellent addition to your collection of Pro Tools plug-ins.