Garmin digital audio panel features 3-D audio

 - March 27, 2011, 3:30 AM

Garmin unveiled the GMA350-series digital audio panel last month with two unique new features for aviation: voice-recognition controls and 3-D audio. The new GMA350 series fits in a box that is pin-compatible with Garmin’s GMA340 series and audio panels made by other manufacturers. The GMA350, said to be the first all-digital general aviation audio panel, comes in fixed-wing and helicopter versions and retails for $2,395 and $2,695, respectively. Both have the same features, but the helicopter unit includes support for a third com, NVG-compatible green annunciation and new split-com modes.

The new features, said Garmin engineer and test pilot Sean Doyle, “are all about reducing pilot workload and improving safety.” The 3-D audio function mimics the way humans process audio, delivering a more natural-sounding result to stereo headphones. Based on research done at the Massachusetts Institute of Technology, 3-D audio spatially separates two different audio inputs. With current audio panels, if a pilot is listening to ATC on one radio and ATIS or weather on another, it is difficult to separate the two audio streams. With 3-D audio, each channel is separated and piped toward opposite sides of the headphones.

During a demonstration of the GMA350H, I found that 3-D audio is much more like hearing multiple conversations and being able to pick out which one I wanted to hear. Switching back to ordinary 2-D audio highlighted the differences. And back on 3-D audio, I was easily able to pick out which audio stream to focus on and which one to ignore, but they weren’t stepping over each other as they would in 2-D audio. “It’s kind of subtle,” Doyle said. Garmin has demonstrated 3-D audio with three audio streams, he added, “and that’s incredibly impressive because you really can listen to any one of those three conversations.”

Voice-recognition technology allows the pilot to control all of the GMA350 audio panel’s functions with voice commands instead of pushing buttons on the panel. To let the panel know that a voice command is coming, the pilot first has to click a trigger switch, which will likely be on the yoke or cyclic, then speak the command. For example, saying “com 1” switches the radio being monitored, and saying “com1 mic” changes the transmitting radio.

Flexibility for Crew, Passengers

Another new GMA350 feature is “blue mode,” which allows for independent routing of audio to passengers or pilots and independent control of volume levels for each audio source. An LED volume indicator bar graphically shows volume levels, so if a back-seat passenger asks for a little bit more volume on the intercom, the pilot can easily see how much to add. The GMA350 also allows passengers to control their intercom isolation state. This eliminates the need for a passenger to ask the pilot to turn on the passenger’s intercom channel.

Split com lets the front-seaters select which com each person can use, adding flexibility to the cockpit. With a three-com radio setup, for example, the pilot can select com 1 and 3 and the copilot com 2 or pilot com 1 and copilot com 2 and 3. The GMA350 also offers audio-leveling. As ambient noise increases, the audio panel automatically boosts the sound like the systems on car stereos that play louder as a car speeds up and generates more ambient noise.

Other features include pilot, copilot and four-/five-passenger stereo intercom, two stereo music inputs, front panel music input jack, five unswitched audio alert inputs for external warning tones and a clearance recorder for playback of the mic-selected com.