"Artificial" reverb was first produced by outfitting an empty room with speakers and microphones to create an 'echo chamber.' Later electro/mechanical devices using mechanical devices such as plates or springs were introduced.

In the 1960's, researchers began exploring ways to simulate natural sounding reverberation using digital computers. With the advent of digital audio processing in the 1970's, digital audio developers began looking at the problem of creating a natural sounding digital reverberator. This turned out to be challenging for several reasons.

The first hurdle is to create a digital process (algorithm) that, while inherently finite, can convincingly mimic an analog, real-world process that is for all practical purposes, infinite. A solution that successfully models a real room faces a second challenge - creating a simulation that actually sounds good (there are many awful sounding rooms in the real world). Finally, the designer must decide on the ways in which the user can modify the effect, which parameters can be controlled and what those parameters do. In making these choices, the designer is creating a 'parametric' digital reverb.

Recently, the first 'non-parametric' reverbs have been introduced - the 'sampling' reverbs. This is a straightforward approach to simulating a room - just sample it. First record (measure) the impulse response of an actual room (at a single listening position) and then use DSP to apply that impulse response to the source material. Voila - you've copied the room perfectly (assuming perfect measurement and perfect convolution, of course). There is no better approach to capturing the naturalness of a real enclosure. But there are some inherent limitations. It's only possible to simulate a single listening position in a given room. This doesn't lend itself to interesting types of user control. It's non- parametric. To change decay time, you must change change rooms. Changing diffusion, listening position, eq all are problematic.

The Reverb 2016 algorithms are something completely different. The 'rooms' that they create could never exist in the real world. They are clever fakes. While they sound natural, they are not. But they are parametric,and this gives the user artistic control not possible in the real world. The user can create a palette of colors and moods. In fact, while it's not possible to create a real world enclosure that sounds and behaves the way these algorithms do, that very fact is a large part of their charm and mystique.

To learn more, follow these links:

• The Eventide SP2016 Reverbs
• People