One of the most exciting additions in Pro Tools LE 7.4 is the Elastic Time feature, which greatly improves the program''s transient detection and time-stretching functionality.
Having significantly leveled the MIDI playing field with the introduction of Pro Tools 7.0, Digidesign has since turned its attention to the needs of loop-based musicians. Ironically, for a program that helped define the notion of nonlinear audio editing, Pro Tools' audio had started to seem downright linear compared with the looping and time-stretching work flows of programs such as Sony Acid and Ableton Live.
Version 7.4 introduces Elastic Time, Digidesign's unique take on making audio as flexible as MIDI. While still less radical than the cell-based approach favored by Live and Cakewalk Project 5, Elastic Time's presence means Pro Tools users will rarely have to stress over combining loops with different original tempos. Many other features — a total of 183 pages of What's New documentation — have been added since we reviewed Pro Tools 7.0, so this review will highlight the most significant new features in version 7.4. (See the online bonus material for a rundown of features new to Pro Tools LE 7.3.) Everything here applies to both LE and M-Powered unless otherwise noted, and nothing here is absent from HD.
I tested Pro Tools LE and M-Powered 7.4 on a dual-core Intel 2.33 GHz MacBook Pro with 2 GB of RAM running Mac OS X 10.4.10. OS X 10.5 (Leopard) is not supported as of this writing, but it should be by the time you read this. Windows XP (SP2) and Vista 32-bit Business and Ultimate Edition are supported. Digidesign notes that there are no known issues with Vista Home and Home Premium — they simply have not been tested for compatibility. Pro Tools users should never upgrade their OS or any component thereof (such as QuickTime), or even spend any money on new hardware, without first checking Digidesign's detailed compatibility documentation at digidesign.com/compato.
FIG. 1: Elastic Time is enabled on a track-by-track basis simply by choosing a suitable time-stretching algorithm.
The most important new feature is unquestionably Elastic Time. It's useful to think of it as a more evolved version of Beat Detective, although it's actually much more than that. Often imitated but never equaled, Beat Detective is Pro Tools' way of time-aligning rhythmic audio and MIDI tracks through a combination of microscopic tempo mapping, groove extraction, beat slicing, and quantization (see “8 Groovy Tips for Beat Detective” at emusician.com).
Elastic Time improves on Beat Detective in at least three important ways. First, it features an improved beat-detecting algorithm that marks transients more precisely and better interprets their rhythmic meaning. Second, there is no floating toolbar with multiple steps. Third, instead of slicing, conforming, and crossfading audio, it time-stretches it.
To use Elastic Time, you simply click on a new-track widget and choose a time-stretching algorithm appropriate to the material (see Fig. 1). The audio regions on that track go offline momentarily as Elastic Time analyzes their transients. If the tempo of the audio is already close to the session tempo, so that Elastic Time knows its musical context, you can simply quantize those transients to the grid, and Elastic Time will time-stretch each slice appropriately. This can be done in real time so that if you change the tempo the audio will immediately adapt, or it can be rendered. As with so many functions in a DAW, the trade-off is CPU cycles spent on real-time processing versus time spent waiting for audio to be rendered. The CPU and RAM hit with lots of real-time Elastic Time tracks can be significant.
Although Elastic Time might seem to make Beat Detective unnecessary, the latter still exists in Pro Tools 7.4. This means you could, for example, extract the timing of a drum loop or recorded performance with Beat Detective and then use Elastic Time to quantize another track to it. Both Elastic Time and Beat Detective require good judgment and occasional tweaking for optimal results. Anyone familiar with the Beat Detective work flow of adjusting sensitivity and adding/deleting/promoting beat triggers (called event markers in Elastic Time) will feel right at home (see Fig. 2).
The implications for music production, especially in styles that rely heavily on loops, are obvious, but Elastic Time can be applied to sample-based tracks as easily as to tick-based tracks. By grabbing a single event marker, you can “telescope” an entire region to compress or expand it to the desired length. This is similar to using the TCE Trim tool, except that you can now drag a specific event within a region — rather than just the end of a region — to a hitpoint. By anchoring one event marker and dragging another, you can “accordion” the region, stretching the audio on either side of the anchor point in opposing directions. To align dialog or Foley, you can drag each event marker individually.
None of this would matter if the time compression/expansion were not adequate, but it is in fact quite good. Five different algorithms are available (one of which will work only in rendered mode), and three of them offer simple but useful controls for optimizing the results. With practice, I was able to find a suitable setting for just about every situation.
Audio can be auditioned at session tempo within the Workspace browser, and it can be automatically conformed on import. Audio can be batch analyzed within the browser so it won't need to go offline for analysis when you import it.
For those times when Beat Detective is still the right tool, you will find an Enhanced Resolution option for analyzing selected audio. This is inherited from Elastic Time, and it is also used by Tab To Transient and Separate Regions At Transients. One of the most anxiously awaited keyboard shortcuts makes its debut in 7.4, too: you can now toggle Tab To Transient on and off by pressing Command-Option-Tab.
FIG. 2: The new Analysis track view allows you to edit individual event markers in conjunction with the Elastic Properties window.
Get Your Mojo
Pro Tools LE 7.4 users with a Digi 003 or an Mbox 2 can now use an Avid Mojo SDI for direct support of Avid video. In a fast-paced video production environment, this makes for a relatively inexpensive workstation for dialog editing, Foley, sound-effects design, and dialog localization. With the Mojo SDI, LE 7.4 supports multiple video tracks, multiple video codecs, general video editing, and more. I did not test Mojo SDI support.
Pro Tools M-Powered finally supports DigiTranslator, so M-Powered users are now fully equipped to move projects between DAWs or between Pro Tools and Avid workstations — at least to the extent that OMF and AAF work for anyone. Under Vista only, 7.4 supports import, playback, and bouncing of Windows Media VC-1 Advanced Profile video files.
The remaining new features in Pro Tools 7.4 include improved handling of REX and Acid files and the ability to receive MIDI from ReWire clients. Structure Free, a limited but still quite useful version of Digidesign's sampler plug-in, is included. For most users, then, upgrading from 7.3 to 7.4 means Elastic Time. It's a big-enough feature that it's certainly worth the $49 upgrade price for anyone who does time correction.
If you are still using version 7.1 or earlier, the long list of 7.3 features in addition to Elastic Time makes the 7.4 upgrade a bargain at $75. Mixer changes can now be made on the fly, allowing you to add plug-ins and change routings without stopping playback (though with a brief audio interruption). Up to 99 window configurations can be stored, recalled, imported, and exported. As always, Pro Tools' documentation is among the best — thorough, well written, and available as PDFs on Digidesign's Web site.
Pro Tools LE 7.4 steps boldly into the fray, providing the sort of original approach to malleable audio that you would expect from an industry leader. Unless you're trying to extend the life of an underpowered computer, it would be silly not to upgrade.
Brian Smithers would like to thank his colleagues at Full Sail Real World Education for their insights and boundless Pro Tools knowledge.
digital audio workstation$250 (M-Powered only; LE available bundled with Digidesign interface only) upgrade from 7.3$49 (download)upgrade from earlier versions$75 (download)
PROS: Elastic Time. Mojo SDI support. Windows Vista support. Outstanding documentation. Structure Free sample player plug-in.
CONS: Persnickety (though well-documented) compatibility grid. No Leopard support as of review date. No surround mixing. M-Powered still doesn't support DV Toolkit 2.
FEATURES 1 2 3 4 5 EASE OF USE 1 2 3 4 5 DOCUMENTATION 1 2 3 4 5VALUE 1 2 3 4 5