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Real-Time Rules
Most of today's popular plug-in formats support realtime processing on playback: You can change the effect as the audio plays; the original audio file is untouched. File-based plug-in formats, on the other hand, actually process the audio files themselves. When you apply a file-based plug-in, you are altering the original audio permanently (or, if you're smart and cautious, creating a completely new audio file). The SD II plug-in format was file-based, as was the Xtras format for SoundEdit 16 version 2. The most popular file-based formats in use these days are Premiere and AudioSuite. Most real-time plug-in formats can also function in file-based mode: Once you decide you like the sound of a realtime effect, you can "print it to disk," thus freeing up processor resources for additional effects.
Although the file-based approach may be appropriate for tasks such as converting material to a different file format, it's generally considered less practical and intuitive than realtime. In most cases, you must set parameters while listening to a small "preview" section of the file, which doesn't allow you to get the full flavor of the track as you tweak the settings. And since the entire file is processed, waiting for results can be time-consuming. Also, a momentary lapse in good backup procedure can make it difficult or impossible to undo your processing decisions later. Still, if you have an older (and slower) computer, file-based plug-ins may be your best (or only) option. But all else being equal, a realtime format such as VST, MAS, or RTAS delivers faster and more flexible results.
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FilterTaps is one of 74 VST plug-ins included with Cycling '74's Pluggo suite. (What's with the "74" thing, anyway? Aren't bellbottoms getting a bit passé?) The vocal track starts dry, then the filtered taps kick in after the first phrase. Note the individual filter frequency controls under "Hz," all of which can be proportionately controlled via mouse using the Global Frequency Scale box.
[sample MP3 (325 kb)]
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According to Seva at Waves, the distinction between realtime and file-based operation doesn't affect the processing algorithms used; it's essentially a function of the API. "Each API has its own set of limitations," he says. "For instance, when Digidesign decided to make AudioSuite realtime, they had to create RTAS, a whole new API."
Waves' underlying software processor code, however, is the same for both realtime and file-based plug-ins. To de-couple the signal processing from the API, Waves develops plug-in "shells" to interface with host applications. The shells, in turn, interface with the individual Waves processing modules for EQ, dynamics, and effects. As a result, Waves can easily mate its plug-ins to a wide range of host apps and formats.
Chart: How the Plug-In Formats Compare
PLUG-IN
FORMAT |
HOST
APPLICATION(S)
& PLATFORM(S) |
DSP HARDWARE
or NATIVE? |
REALTIME
or FILE-BASED? |
SUPPORTS
AUTOMATION? |
| Adobe Premiere |
multiple
applications (MacOS) |
native |
file-based |
no |
| Digidesign
AudioSuite |
Digidesign Pro Tools (MacOS/Win) |
native |
file-based |
no |
| MicrosoftDirectX |
multiple
applications (Win) |
native |
realtime |
no |
| Mark
of the Unicorn MAS |
MOTU Digital Performer (MacOS) |
native |
realtime |
yes |
| Digidesign
RTAS |
Digidesign Pro Tools 5.0 LE (MacOS/Win) |
native |
realtime |
yes |
| Digidesign
TDM |
multiple applications (MacOS/Win) |
DSP
hardware |
realtime |
yes |
| Soundscape
Mixtreme |
multiple applications (Win) |
DSP
hardware |
realtime |
yes |
| Steinberg
VST |
multiple applications (MacOS/Win) |
native |
realtime |
yes |
More info:
www.steinberg.net
www.digidesign.com
www.emagic.de
www.motu.com
www.soundscape-digital.com
www.microsoft.com/directx/
www.adobe.com
www.arboretum.com
www.tcworks.de
www.cakewalk.com
www.bias-inc.com
www.syntrillium.com
www.sonicfoundry.com
www.waves.com
www.wavemechanics.com
www.duy.es
www.lexicon.com
www.focusrite.com
Next Page: Audio Samples and Screenshots
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