Open-ear audio

Open-ear audio is personal sound delivered to a listener without blocking or covering the ear canal, so that the wearer hears device audio and the surrounding environment at the same time. It is produced either by small air-conduction speakers placed near the ear, as in audio smart glasses and the integrated speakers of many head-mounted displays, or by bone-conduction transducers that pass vibration through the skull to the inner ear. Manufacturers use the phrase directly: Meta described the speakers in its Ray-Ban Stories glasses as "open-ear speakers", and Amazon says its Echo Frames use "open-ear audio".

In research on audio augmented reality, open-ear devices are described as passively acoustically transparent: the ear canal stays open enough for virtual and real sounds to be heard together without any microphone processing. The approach is used in audio-first smart glasses such as Bose Frames, Amazon Echo Frames and the Ray-Ban Meta line, and in VR headsets such as the Valve Index, whose off-ear speakers let the listener's own ears and head shape the sound. The main costs are sound leakage to people nearby, the difficulty of delivering enough loudness and bass, and, for bone conduction, a less even frequency response and weaker spatial cues.

Reviewed 6 October 2026. Checked every cited source (McGill 2020, Stenfelt 2005, Wang 2022, MacDonald 2006, Lindeman 2008, Voong 2019, Sawhney 2000, Albera 2026, Watanabe 2025, Tran 2026, Shokz patent, Valve, Amazon, Bose, Meta, Apple and press pages) against the text, including quotes, dates, prices and DOIs. About review dates.

Definition and terminology

Open-ear audio is defined by what the device does not do: it does not seal, plug or cover the ear. Closed headphones and in-ear earbuds occlude the ear, and some of them use microphones to recreate the outside sound electronically. McGill, Brewster, McGookin and Wilson, in a 2020 CHI paper, separate these into passive acoustic transparency, "where the ear canal is sufficiently open to hear both virtual and real sounds concurrently", and active transparency, in which noise-cancelling headphones or earbuds use microphone arrays to mix selected real-world sound back in. As passive examples they list bone-conduction headsets and directional speakers built into glasses frames, naming Bose Frames and Amazon Echo Frames.

The active alternative has its own research history. In 2004 Aki Härmä and six co-authors described mobile augmented reality audio (MARA), in which binaural microphones are built into stereo earphones and their signals are routed straight to the earphones, giving the user a "pseudoacoustic" copy of the real environment into which virtual sounds are mixed. In a 2008 paper, Robert W. Lindeman, Haruo Noma and Paulo Gonçalves de Barros described two approaches to audio AR that they had introduced earlier. In "Mic-Through AR", real-world sound is captured by two microphones and mixed with computer-generated sound for playback over standard headphones. In "Hear-Through AR", which they present as analogous to optical see-through AR, computer-generated audio is delivered through bone conduction while real-world sound reaches the unoccluded ear canals directly, so that the mixing takes place at the cochlea.

Terminology varies by maker. Meta and Amazon say "open-ear"; Valve calls the Valve Index speakers "ultra near-field, full range, off-ear (extra-aural) headphones"; and a 2024 patent assigned to Shenzhen Shokz is titled "Open earphones".

How it works

Air-conduction open-ear speakers

Audio glasses and many VR headsets with built-in audio use small loudspeakers placed near the ear. Bose described the speaker in Bose Frames as "a miniscule, wafer-thin acoustic package" set into the interior of each arm instead of an earbud or attached component. Amazon says that Echo Frames place the audio in the temples and direct sound toward the ears "while keeping your ears uncovered".

Because nothing seals the speaker to the ear, the design problem is to deliver enough sound pressure to the ear canal while radiating as little as possible to everyone else. In Amazon's description of the Echo Frames engineering, "with an open-ear design, sound has to travel farther, and there is less control over direction". Amazon's answer was a dipole speaker configuration: one sound port sits near the ear canal and a second port "cancels unnecessary sound while amping up bass". The team measured leakage with a rotating arch of microphones and moved the speakers closer to the ear to reduce leakage and raise loudness. The Shokz patent describes the same principle. Two sound holes form a dipole sound source, and far-field sound leakage is reduced by the inversion and cancellation of the two sound waves. The patent also notes that the reduction weakens as frequency rises, and that above a certain frequency (it gives about 8000 Hz as an example) a dipole can leak more than a single point source.

Valve reached a similar result with an open-backed driver. Each Valve Index ear speaker is a 37.5 mm Balanced Mode Radiator (BMR) with a stated frequency response of 40 Hz to 24 kHz. Valve explains that the front and rear pressures of an open-backed driver are out of phase, and the driver's own diameter provides some "self-baffling". Below about 3 kHz, where most audio content lies, the cancellation is strong, "preventing sound from bothering people nearby"; above that frequency there is no cancellation. Because the wearer's ear is in the near field, the cancellation is not heard by the user.

Bone conduction

Bone-conduction devices vibrate the skull instead of moving air at the ear. Research systems have placed the transducers at positions including the mastoid, the condyle and the temple. Hearing by skull vibration has been known since the 19th century. In a 2005 review in Otology & Neurotology, Stefan Stenfelt and Richard Goode list five contributing mechanisms: sound radiated into the ear canal, inertia of the middle-ear ossicles, inertia of the cochlear fluids, compression of the cochlear walls, and pressure transmission from the cerebrospinal fluid. Of these, the inertia of the cochlear fluid appears most important. They also note that bone conduction is a less efficient route to the cochlea than air conduction.

The limits matter for spatial audio. Wang and colleagues note that the largest interaural time difference available through bone conduction is about 0.2 ms, against up to about 0.65 ms for air conduction, and that the limited interaural level and time differences make it difficult for listeners to isolate stimulation presented to either side of the skull. Voong and Oehler measured an uneven frequency response for bone-conduction headphones compared with conventional headphones or loudspeakers. McGill and colleagues wrote that bone-conduction headphones "have enabled open-ear acoustically transparent audio for years" but that their fidelity has limited uptake.

History

Wearable open-ear audio for computing predates consumer smart glasses. The MIT Media Lab's Nomadic Radio project, by Nitin Sawhney and Chris Schmandt, used the SoundBeam Neckset, a research prototype patented by Nortel for hands-free telephony. It had two directional speakers mounted on the user's shoulders and a directional microphone on the chest. The authors argued that headphones were not entirely suitable in urban environments where users need to hear traffic, and that body-worn speakers could provide directional sound "without covering the ear". Volume could be set so that the user mainly heard the output while staying within conversational distance of other people.

The table lists notable XR and smart-glasses products and milestones that use open-ear audio.

Date	Product or milestone	Open-ear method	Notes
April 2013	Google Glass Explorer Edition specifications published	Bone conduction	Mono audio through a bone conduction transducer
December 2018	Bose Frames announced	Speakers in the frame arms	US$199; US availability from January 2019; described by Bose as the first commercial product embedded with its Bose AR platform
March 2019	Oculus Rift S announced	Speakers in the headstrap	Uses "the same integrated audio system as Oculus Quest and Oculus Go", plus a headphone jack; Road to VR described it as an open-ear solution replacing the original Rift's on-ear headphones
September 2019	Amazon Echo Frames announced	Speakers in the temples	No camera or display; US$179.99; invite-only Day 1 Editions program
September 2021	Ray-Ban Stories launched	Open-ear speakers in the frame	From US$299
June 2023	Apple Vision Pro announced	Dual-driver audio pods next to each ear	Personalized Spatial Audio based on head and ear geometry
September 2023	Ray-Ban Meta announced (pre-orders from 27 September; retail availability from 17 October 2023)	Open-ear speakers in the frame	New speakers with "improved directional audio that provides reduced audio leakage"
February 2025	Nuance Audio receives FDA clearance	Speakers in the frame arms	EssilorLuxottica's over-the-counter hearing-aid glasses
September 2026	Ray-Ban Meta Audio announced	Speakers behind cut-outs in the temples	Camera-free audio glasses; pre-orders from US$349, shipping 13 October 2026

Bose marketed the Frames as carrying "the world's first audio augmented reality platform". Bose AR used a 9-axis head motion sensor in the glasses and the GPS of the paired phone to determine where the wearer was and which way they were facing. In June 2020 TechCrunch reported that Bose was discontinuing the platform, which it had introduced at SXSW in 2018; a spokesperson said that "Bose AR didn't become what we envisioned".

Applications in VR and AR

VR headsets

Valve published a detailed rationale for open-ear sound in VR in its account of the Valve Index audio design. Valve wrote that sealing the ear with over-ear headphones can trap heat and make a headset feel hotter, that some playtesters felt headphones touching the ear signaled that the coming sound "wasn't going to be real", and that "delivering sound directly into the ear canal bypasses the natural listening process caused by ear and head interacting with real sound waves". It added that a headphone's own coloration can interfere with the head-related transfer function (HRTF) filters that spatial audio depends on for direction. Valve placed the speakers close enough to the ear to work like player-relative stereo headphones for existing VR content, but far enough away to let the ears and head add their own tonal coloration, while also addressing comfort and pressure issues. It chose BMR drivers from Tectonic partly because they reduced coloration when the speaker was slightly mispositioned.

Oculus made a similar change in its PC headsets. Road to VR wrote that one of the main changes from the original Rift to the Rift S "was the removal of the on-ear headphones in favor of an open-ear audio solution using speakers in the headstrap". Its review found the audio lacking, and Facebook's Nate Mitchell said the team was tuning the audio driver software and algorithms to improve bass and overall volume in a later update. On the Apple Vision Pro, Apple says that "flexible straps ensure audio remains close to the user's ears" and that two individually amplified drivers in each audio pod deliver Personalized Spatial Audio.

Smart glasses and audio AR

Audio glasses without a display rely on their speakers for music, calls and voice-assistant responses. Meta said in September 2026 that audio "has been our most popular feature since day one because our glasses give you high-quality sound without closing you off from the world around you". In its 2023 launch announcement for Ray-Ban Meta, the company described new custom speakers with extended bass, higher maximum volume and reduced audio leakage. Head tracking in some glasses supports location-aware audio, as with Bose AR's use of a head motion sensor and phone GPS.

Hearing assistance is a newer use of the same hardware. EssilorLuxottica describes Nuance Audio as "an open-ear hearing solution" built into smart glasses, aimed at people with mild to moderate hearing loss. A 2026 study in Acta Otorhinolaryngologica Italica describes the glasses as integrating a multi-microphone array, a signal processor and miniature speakers into the frame arms, delivering air-conduction amplification without in-ear components. In 32 adults with age-related hearing loss it measured improvements in aided pure-tone thresholds and speech reception thresholds. At Meta Connect 2026, Meta announced hearing enhancement, which it describes as FDA-cleared software for adults with perceived mild to moderate hearing loss, for supported AI glasses. Meta said it would launch in the US later in 2026 at US$149.99 or with a Meta One subscription.

Research

Several studies have tested whether open-ear devices can carry spatial audio and how they change the experience of mixing real and virtual sound.

Study	Devices compared	Main finding
MacDonald, Henry and Letowski (U.S. Army Research Laboratory), International Journal of Audiology, 2006	Stereo headphones and a stereo bone-conduction system, using individualized HRTFs at eight horizontal positions	Localization was "nearly identical" for both, so bone conduction could display spatial information
Lindeman, Noma and Gonçalves de Barros, IEEE Virtual Reality, 2008	Speaker array, headphones and a bone-conduction headset	Speaker array most accurate for stationary sounds; no accuracy difference between the speaker array and bone conduction for moving sounds; both beat headphones for moving sounds
Voong and Oehler, IEEE VR, 2019	Conventional and bone-conduction headphones with best-fitting HRTF profiles chosen by a tournament method	Tournament ratings correlated better with localization for conventional headphones; bone-conduction headphones had an uneven frequency response
McGill, Brewster, McGookin and Wilson, CHI, 2020	Bose Frames and Bose NC700 noise-cancelling headphones, indoors and on a walking route (15 participants)	Differences in presence, realness and externalization for some content types; transparency perceived as safer
Wang et al., Trends in Hearing, 2022	Bilateral bone conduction at five head positions, and air-conduction headphones	Mastoid best and temple worst; mastoid and condyle not significantly different from headphones in localization accuracy
Watanabe et al. (NTT), CHI, 2025	Five wearable audio devices with different shapes and transparency modes	Devices with high transparency were more likely to draw attention to real-world sounds during the audio AR experience, and that experience was rated enjoyable and natural

Lindeman's group also reported that subjects' comments after the experiment supported the performance data. In the 2025 NTT study, two demonstration experiments showed that adding virtual sounds through open-ear earphones to real content could produce effects such as distance enhancement. Voong and Oehler pointed to navigation aids for visually impaired people as one use, since bone-conduction headphones leave the outer ear free to hear environmental sounds.

Limitations

Sound leakage is a social cost of leaving the ear open. In the 2020 McGill study, almost all participants agreed that acoustic transparency would be a key feature in future headwear purchases. Personal safety came up repeatedly, including awareness of cars as pedestrians. Yet after wearing the Bose Frames, just under half of participants were concerned that others could overhear their audio. The same tension appeared two decades earlier in Nomadic Radio, where an officemate overheard synthetic speech playing on a user's neck-worn speakers. A 2026 paper by University of Sydney researchers on everyday audio AR, released as an arXiv preprint, describes leakage from open-ear and bone-conduction designs as a form-factor concern that can project snippets of augmented sound into shared spaces; its participants noted that this undermines the assumed privacy of audio AR.

Volume and bass are the other constraint. Amazon's engineers note that sound must travel farther and is harder to direct, and dipole cancellation, used in several designs to limit leakage, becomes weaker at high frequencies. Road to VR's review of the Rift S found its headstrap speakers too quiet at times, which Facebook planned to address in software. The Valve Index and the Rift S also have a headphone output, so wearers can connect their own headphones.

See also

• 3D audio
• Binaural audio
• Head-related transfer function
• Smart glasses
• Bose Frames
• Amazon Echo Frames
• Ray-Ban Meta Audio
• Valve Index