US Air Force Adopts Spatial Audio For F-16 Headsets

Noise-cancelling headphones are part of everyday life for millions of people. If you have an interest in personal audio tech, you might know that active noise cancellation got its start in the field of aviation. In the 1950s, the renowned engineer and inventor Lawrence J. Fogel began submitting patents for active noise cancellation systems designed to improve communication for pilots, while protecting their hearing at the same time. Later, in 1989, Bose introduced the first commercially available active noise cancellation headset, the Aviation Headset Series I. And after providing noise-cancelling headphones for airline passengers in the late 1990s, Bose launched the first Quiet Comfort noise-cancelling headphones for the consumer market in 2000. The rest, of course, is history. Now, in an interesting reversal of the flow of technological adoption, spatial audio technology first used by entertainment-focused companies, like Dolby and THX, is finding its way into the cockpits of advanced military aircraft.

The Danish aerospace company Terma has recently secured a contract worth $9 million to outfit the US Air Force’s F-16 fighter aircraft with an advanced “3D-Audio” system. According to the company’s website, Terma Group develops products and systems for defense and non-defense security applications, including command and control systems, radar systems, self-protection systems for aircraft, space technology, and aerostructures for the aircraft industry. The innovative 3D-Audio system falls under the company’s Self-Protection System (SPS) umbrella. Over the next two years, the US Air Combat Command will upgrade its fleet of F-16 jets with Terma’s in-helmet 3D-Audio solution — the first of its kind available on the market. The system is designed to improve situational awareness, reduces stress and fatigue, and ultimately improve the likelihood of survival for pilots on active missions.

According to Terma, the 3D-Audio system spatially separates audio signals, aligns threat alarms and other signals with directional information, and integrates active noise reduction in order to eliminate the “crowded room” effect that pilots can suffer from when too many audio sources are coming through their headsets. The spatial audio system reportedly helps separate voices from other sounds, and places them in different virtual locations around the pilot’s head, helping the pilot respond quickly and accurately. For example, the voice of a pilot’s wingman becomes more easily distinguishable from that of someone in the control tower.

Using our 3D-Audio system, pilots perceive an approaching missile threat 1.5 seconds faster compared to when threats are presented only on the cockpit panel display. Seconds are gained that could be vital for mission success and the safety of your pilots and platforms. The benefit of switching to a 3D-Audio separation function is ultimately faster and better decisions. Your pilots quickly become aware of the details in mission-critical situations, which makes their response time… faster than the enemy’s.

— Terma

The 3D-Audio system also augments visual cues, helping pilots to more quickly determine the relative importance of various voices and sounds. Terma says that pilots are exposed to audio coming from several different sources all at once, and this naturally adds to the stress of the job. When sounds are placed in different positions in the sound field to correspond with visual cues from the cockpit display, it is easier for the pilot to discern which audio cue is associated with which source. The 3D-Audio system applies direction to audio cues for aircraft subsystems, linking the auditory information with the visual display. This reportedly leads to higher accuracy and quicker reaction times. Terma’s in-helmet system also prioritizes the most important sound sources, such as missile alerts and instructions from air traffic control. At the same time, distracting sounds such as engine noise and electrical interference are reduced.

As you can imagine, the ability to quickly pinpoint the direction of immediate threats might mean the difference between life and death for a pilot in a fighter jet. But the spatial audio cues can also clarify navigational signals and other helpful information. In addition to directional information, other binaural audio cues — including distance and movement — help to simulate real-life sound positioning. Traditional audio cues, like simple warning tones and beeps, take longer for a pilot to process and respond to. Being able to naturally sense the location of an enemy aircraft, for example, has obvious benefits. Terma says that its system includes 3D-Audio cues for all of the following:

• Missile Warning System threats
• Radar Warner Receiver threats
• Laser Warner System threats
• Threats from small arms detection systems
• Indication of direction to beacon in Search & Rescue operations
• Indication of terrain obstruction warning and cueing

Terma 3D-Audio Head-tracking

A critical part of the 3D-Audio system is head-tracking, which intelligently positions an audio source relative to the listener’s head. In a traditional headphone system, the perceived location of a sound source moves when the listener’s head moves. If a sound is in the left channel, it always sounds like it’s coming from your left, no matter which direction you are facing. By contrast, head-tracking creates a real-time audio simulation of the audio environment, allowing the listener to perceive and understand the sources and locations of sounds, regardless of head orientation and movement. So if a sound is coming from your left, and you turn to face the sound source, it now sounds as if it’s right in front of you. 

In a headphone-based home theater environment, head-tracking can anchor the dialogue to the action on the screen. But for a pilot, it can be a life-saving functionality. As the pilot moves around, a dynamic audio source indicating an incoming rocket-propelled grenade or radar-guided missile is delivered with critical directional information intact.

With this (US Air Force contract), the 3D-Audio program continues to be a significant cornerstone of our offerings to meet the demand for best-in-class audio systems from the global community.

— Rob Strasser, Vice President of Terma Self-Protection Systems

Terma says that its 3D-Audio system is compatible with all aircraft types. Terma outfitted the US Air Force’s A-10C Thunderbolt II ground-attack jets with its 3D-Audio and active noise reduction system in 2019.

More information: Terma