Making Sense of Plug-In Formats

Thinking of a Digital Audio Workstation, or some plug-ins to enhance your current rig? Your signal processing options can be amazingly diverse -- and confusing. Before you wind your way through the plug-in jungle, here's what you need to know

by Philip De Lancie
June 28, 2000

At the center of a profound change in audio production over the last decade, the digital audio workstation (DAW) has achieved professional parity with traditional consoles and recorders. It's hard to resist the productivity and creative flexibility offered by packages that roll recording, editing, and mixing into a single working environment. But just as no studio is complete without its outboard processors, the story of the DAW is incomplete without the "plug-ins" that bring signal processing into the workstation domain. By adding reverb, EQ, compression, and even software synthesis into your digital mix (plus just about any other effect you can think of), plug-ins act as the spice that makes the DAW recipe work.

Plug-ins are discrete software modules that operate from within a host application. The plug-in concept is widely used in software engineering to customize and extend the capabilities of host software. In audio, plug-ins really began attracting attention when Israeli software company Waves debuted the Q10 parametric EQ for Sound Designer II several years ago. SD II may be gone, but the plug-in market has exploded. There are now literally hundreds of audio plug-ins available from dozens of vendors, covering processing tasks ranging from the essential to the bizarre.

No "Standards," Plenty of Formats
Without question, the proliferation of plug-ins has added to the quality and variety of processing tools for DAWs. But as anyone who's tried to wade through the alphabet soup of format names can attest, trying to figure out which formats work in which environments can be pretty confusing. There are no plug-in "standards" in the sense of specifications that are formally recognized by standards-setting bodies such as ANSI or IEC, or even recognized within the audio industry by AES or SMPTE. Instead, plug-in formats are defined by the API (Application Programming Interface) that allows a given plug-in to work with the host application. A plug-in designed to work with a given API should work within any host application supporting that API.

Many plug-ins are available in more than one format, and a few host applications support multiple plug-in formats. But it's not economically feasible for plug-in vendors to release every plug-in in every format. The most popular current formats include:

• Adobe Premiere
• Digidesign AudioSuite
• Microsoft DirectX
• Mark of the Unicorn MAS
• Digidesign RTAS
• Digidesign TDM
• Soundscape Digital Mixtreme
• Steinberg VST

Different Strokes...
Although individual processing applications can vary widely, plug-in formats fall into two broad categories:

• DSP hardware-based: in which one or more digital signal processing chips (beyond your computer's CPU) is used to perform the processing
• native processing-based: in which your computer's central processor unit (CPU) performs all the "number crunching" necessary to perform the signal processing.

(Click on the links above to learn more about either of these categories.)

In addition, plug-in processing can be file-based or can operate in realtime. For more about the differences between these two approaches, click here.

Given the number of different plug-in formats out in the market, how does a company like Waves -- a high-profile plug-in developer without a stake in the host-application market -- decide which formats merit support? "We have to look at the size of the market," says Seva of the Waves U.S. office, "and what it's going to take to penetrate and support it, both in terms of the marketing costs and the engineering resources. We have to pick and choose."

Essentially, that's what well-informed workstation shoppers are doing every day, factoring the features they need -- such as automated EQ, realtime effects processing, and acceptable latency -- against cost, flexibility, and broad third-party support.

Next Page: DSP Hardware-Based Plug-Ins