This article is a science explainer on bone conduction headphones.
1. Working principle
Sound has three basic attributes: loudness, pitch, and timbre. Sound is produced by vibrating objects and propagates as waves through a medium (air, solids, or liquids), which can be perceived by auditory organs.
Bone conduction is a mode of sound transmission that converts sound into mechanical vibrations of various frequencies, which are transmitted through the skull, the bony labyrinth, inner ear fluids, the organ of Corti, and finally to the auditory centers.
Compared with the conventional diaphragm-based air conduction path, bone conduction bypasses many intermediate steps of acoustic transmission. It can reproduce sound more clearly in noisy environments and does not radiate sound into the surrounding air to affect others. Bone conduction technology includes both bone conduction speaker technology and bone conduction microphone technology.
Bone conduction speaker technology is used for playback. Air-conduction speakers convert electrical signals into sound waves (acoustic vibrations) that reach the auditory nerve via the air pathway. Bone conduction speakers convert electrical signals into vibrations that are transmitted directly through bone to the auditory nerve. The transmission media differ.
Bone conduction microphone technology is used for reception, i.e., collecting sound. Air-conduction reception involves sound waves traveling through air to a microphone, whereas bone conduction reception transmits vibrations through bone.
Headphones built with these technologies are called bone conduction headphones, also referred to as bone-guided or bone-sensing headsets.
2. Advantages and disadvantages
Advantages
Safer
Bone conduction headphones rest on the cheekbones in front of the ears, transmitting sound through the skull to the inner ear while keeping both ear canals open. Users can remain aware of ambient sounds while listening, making them suitable for outdoor activities, public transit, and other situations where awareness of the environment improves safety.
More hygienic
Because they do not need to be inserted into the ear canal, bone conduction headphones help maintain hygiene inside the ear, avoiding the heat and potential bacterial buildup associated with in-ear designs. Their smooth external surfaces are easy to clean, whereas in-ear models can accumulate debris and microbes.
Healthier for hearing
The vibration levels delivered by bone conduction devices are generally lower than those from typical headphones, which can reduce damage to cochlear hair cells by roughly 80% according to some estimates. Therefore, bone conduction may be a healthier option for long-term listening compared with conventional headphones.
Protects hearing
Because the transducer's vibrations do not need to pass through the eardrum, they reduce eardrum fatigue and can help protect hearing. The fixed placement on the head also makes them less likely to fall off during exercise, which benefits users who listen while running.
Comfortable to wear
Bone conduction models typically use an ear-hook or behind-the-ear form factor and do not enter the ear canal. This avoids discomfort from prolonged pressure inside the ear and provides secure fit during activity, offering a different comfort profile than in-ear headphones.
Disadvantages
Not suitable for sleeping
The ear-hook design can be uncomfortable or get pressed when lying down, so bone conduction headphones are generally not suitable for wearing while sleeping.
Inferior timbre
Because sound must pass through skin and bone before reaching the ossicles, separation and fidelity can be weaker than with in-ear headphones.
Sound leakage
Bone conduction transducers do not always make perfect contact with the skull, and some energy can convert to airborne vibrations, which may cause audible leakage.
Lack of immersion
Bone conduction releases the ear canals, eliminating the passive isolation or noise reduction that sealed in-ear or over-ear designs provide. In very noisy environments, perceived volume or clarity may be insufficient.
3. Market situation
Data show that in 2022 shipments in China's Bluetooth headphone market fell 18.1% year-on-year, while bone conduction headphone shipments rose 123.6% year-on-year.
In the first quarter of 2023, global shipments of personal smart audio devices (including TWS, wireless over-ear, and wireless neckband products) fell 15% to 86.72 million units. TWS shipments declined 10% to 61.58 million units.
The global bone conduction headphone market has concentrated into a duopoly with two leading vendors, Nank and Shaoyin. Together they hold roughly 35.6% and 33.2% of the market respectively, accounting for nearly 70% of the market.
Bone conduction headphones have created a new growth point through their open fit and wearing comfort, and market sentiment has generally been positive. However, rapid growth can quickly approach a saturation point.
Prices in the bone conduction headphone market are relatively high, generally at or above CNY 1,000.
Recent global market reports indicate that from 2021 to 2022 the bone conduction headphone market increased from 5 billion to 8.9 billion, a 78% year-on-year rise.
Rapid market expansion also moves the category closer to a ceiling. As a niche segment, bone conduction is not the main route for many large manufacturers; it is typically more expensive than mainstream TWS products and lacks clear advantages in sound quality or health benefits. Combined pressure from OWS and TWS products may limit the duration of rapid growth.
