App. #2
Application Notes

Application Note #2
Corporate Audio/Video Presentations with the MTI-3 TriSonic Imager

Benefits For The Corporate A/V Professional

The Miles Technology MTI-3 TriSonic Imager provides a wide range of benefits that can enhance your audio and "audio for video" in the corporate market. Its patented TriSonic Imaging process does not dynamically modify the signal; instead it provides clean, open, and uncolored left-center-right sound with full-bandwidth (20 Hz to 20 kHz) surround sound.

The TriSonic center channel adds another dimension to the program material. It pulls out subtleties in the mix, and provides a fuller sound with a true stereo image delivered to every seat even to listeners located at the extreme sides.

The center channel firmly anchors dialog or other central sounds to the center of the video screen.

The sound of the center channel can be fine tuned with the MTI-3. For example, vocals in a stereo mix can be emphasized or de-emphasized as needed with a simple front-panel adjustment. And a live vocal channel can be a "point-source" through only the center channel or distributed to the loudspeaker array as desired.

Also, with a simple adjustment, the apparent stereo soundstage can be widened beyond the left and right loudspeakers, for a dramatic "wide-stage" effect.

The surround channels add further depth to the sound and can enhance or emphasize all types of effects. The overall impact of surround sound draws the audience further into the production. In most cases, small low-power loudspeakers are effective and beneficial.

Using the SpreadSound process, mono sources can be enhanced to sound like high-quality stereo sound.

The MTI-3: A Brief Description

The MTI-3 is a high-fidelity multichannel stereo audio processor. Using TriSonic Imaging technology, it creates left, center, and right outputs from any standard stereo signal. Combined with correct loudspeaker placement, the MTI-3 enables outstanding stereo imaging performance, with precise sound-source localization, over a very large listening area. Front-panel controls allow optional adjustments to further tailor and optimize the sound to meet any need. The unit also provides full-bandwidth, high-quality surround outputs for professional surround-sound systems.

Field Application: Fortune 500 Corporate A/V

Chas Gerber has spent more than 20 years designing systems and mixing live productions; for the last 10 years he has specialized in corporate A/V sound. He serves a Fortune 500 clientele, including Reebok, Lotus, and several others.

He first used the MTI-3 for Lotusphere '96 at Disney World's Dolphin Hotel, a show for more than 7,000 attendees featuring a Cirque-du-Soliel-type theme. Gerber's goal was to supply high-quality stereo sound to the entire audience including those seated at the extreme left and right. Two large video screens flown across the soundstage further complicated the design.

Mono Doesn't Cut It

Mono sound would have been the easiest solution, but the show was music-intensive and included stereo sources. Gerber has tried other solutions for situations like this, such as alternating left and right clusters, but with disappointing results. Sometimes static designs like this are ruined by the inevitable last-minute seating configuration changes.

His optimum design utilizes left, center, and right EAW KF Series loudspeaker arrays fed by an MTI-3 TriSonic Imager. The left and right loudspeaker clusters were positioned to the extreme sides of the video screens, and the center cluster was flown between the screens.


The results were spectacular, according to Gerber, with clean, open stereo sound supplied to every seat while the sound system stayed nicely out of the way. The three loudspeaker arrays kept the sound stage tightly linked with the video screens. Using the MTI-3's TriSonic Balance control, he was also able to push the left and right sound field wider than the room when appropriate.

At the 1996 Reebok Global Summit, Gerber faced another problem that he solved with the MTI-3. An important part of the show was the premiere presentation of several new Reebok TV commercials. Mixed at post houses around the globe, the soundtracks of these commercials are plagued with inconsistency.

Vocal Problems Solved

As Gerber explains, "Sometimes you really need to bring the vocal out, and sometimes it needs to be pushed back. With the MTI-3, we could tweak the vocals as necessary, and on the fly, because the unit is so easy to operate."

He has devised a convenient method for patching the MTI-3 into the mixing console, usually a Yamaha PM-3500. Using the matrix section of the console, he assigns left/right playback to left/right master faders. The MTI-3 is inserted into this path; that is, the left/right insert sends are routed to the left/right inputs of the MTI-3, with the unit's left/right outputs then routed back via insert returns.

Meanwhile, the MTI-3's center output is routed to subgroup 8 of the console. With this configuration, left, right, and subgroup 8 (center) can all be dialed into the console matrix and assigned to the loudspeakers. See diagram below.

A New Solution

"My challenge as a sound designer serving this market is to always be open to change, to always seek new solutions like the MTI-3. This ensures consistently successful shows, and in turn, ensures a very happy client," Gerber concludes.

For more information or additional application notes regarding TriSonic Imaging, the MTI-3, or other Miles Technology products, call 800-280-8572 or write to 1826 S. Third St., Niles, MI 49120.

Application Notes