OWS open-back headphones listen to the "core"

Driven by Apple, TWS (Ture Wireless Stereo) true wireless stereo headphones have emerged. From the semi-in-ear AirPods1 launched in 2016, to the in-ear AirPods2 in 2018 and the semi-in-ear AirPods3 in 2021; from semi-in-ear to in-ear, and then to semi-in-ear, it has undergone many generations. The structure of in-ear and semi-in-ear headphones that penetrate deep into the ear canal isolates some noise, and the ANC active noise reduction algorithm technology filters most of the noise, which has certain advantages in noise reduction . Therefore, consumers initially blindly pursued noise reduction effects and liked to use in-ear headphones to isolate external noise as much as possible, but ignored the discomfort of the ears. However, in recent years, "headphone wearing comfort" has attracted more and more attention from consumers, and in 2023 it has become the primary consideration.

Figure. Phoenix.com: Top 10 purchase drivers for true wireless earbuds in 2023

In 2021, Oladance first proposed the concept of OWS (Open Wearable Stereo), or "fully open headphones", at the Global TWS Industry Summit, which can bring a more comfortable experience, bringing new opportunities to the headphone industry. Subsequently, manufacturers such as Sony, Shokz, Cleer, and Huawei joined in and launched their own OWS headphone products, making OWS headphones more and more popular and their market share continues to expand. The "I Love Audio Network" report shows that the frequency of OWS headphone keywords has been steadily increasing every year, and has soared by nearly 153% in the past three years. It is believed that OWS will be a new direction for the true wireless headphone market.

Synergy is a subsidiary of Synergy, which has rich industry experience and professional technical strength in the field of TWS. Simon Huang, senior FAE of AIoT (Artificial Intelligence and Internet of Things) Division of Synergy, said that OWS is another innovative form of headphones after TWS, which has great development potential, but at the same time, OWS headphones have always had technical pain points such as music leakage, call echo and wind noise, and battery life. He recommended Wuqi's WQ7034MX Bluetooth SOC chip, which can greatly optimize these problems.

Simon introduced that Wuqi, as one of the earliest suppliers in China to bring open headphone solutions to the market, has been deeply involved in the true wireless headset (TWS) market for many years, is familiar with the advantages and disadvantages of TWS products in all aspects, and is also the first manufacturer to focus on OWS open headphones. From the early WQ7033MX solution launched to quickly switch from in-ear to open, to the later WQ7034MX upgrade solution launched to further seize this blue ocean, which occupies less memory space, consumes less power, and has richer expansion interfaces, Wuqi has always been at the forefront of the industry. Once the mature WQ7034MX solution was launched, it received widespread acclaim because it can effectively help customers introduce production more quickly and stably. For technical pain points such as music leakage, call echo and wind noise, and battery life, the WQ7034MX series provides a new technical improvement method.

Pain point 1: OWS music leakage

Compared with traditional in-ear headphones, open-ear headphones have greater leakage in the low-frequency part; when the volume is reduced, the auditory gain of the low-frequency part is reduced more; and the WQ7034MX provides a dynamic EQ algorithm, which can maintain the output gain of the low-frequency part (such as 100Hz, the frequency is adjustable) unchanged when the volume is reduced, and has a DSP smoothing processing function to eliminate the POP sound when the EQ is frequently switched.

Due to the limitation of the shape, even if the open-ear headphones are fully loaded in the low-frequency band, their sound quality is still not comparable to that of traditional in-ear headphones. Wuqi has independently developed a virtual bass algorithm for open-ear headphones, which can combine psychoacoustic theory with limited output to make the low-frequency sound of the headphones even better.

Pain point 2: OWS call echo structure

The characteristics of the OWS call echo structure include: short mic-spk spacing, weak acoustic isolation, low signal-to-reply ratio, relatively in-ear, ERL is nearly 20dB small, and the call echo and double-talk effect are poor. Wuqi WQ7034MX provides advanced recurrent neural networks and convolutional neural networks, which are trained with a large amount of data (40G) and are not limited by the type of noise, and are suitable for many call scenarios; LMS+KLM dual filter structure, linear echo suppression capability of 30dB, nonlinear residual echo introduced AI processing, OWS single-talk and double-talk calls are clear and echo-free.

Pain point 3: OWS call wind noise

OWS earphones have always had problems such as residual wind noise, severe voice damage, and low call intelligibility during calls. In response to this, Wuqi WQ7034MX provides multi-microphone technology + neural network algorithm, and trains the AI ​​model through a large amount of wind noise data (8G). Based on the human ear hearing mechanism, it protects voice and achieves the effect of less residual wind noise, stable voice, less damage, and high intelligibility.

Pain point 4: OWS battery life

The spatial sense of sound is mainly affected by the time difference of sound waves reaching the two ears; the sound pressure difference perceived by the two ears (the sound pressure difference perceived by the human ear is different when facing the sound source and facing away from the sound source); and the difference in timbre sound waves reaching the human ear (timbre sound waves reach the human ear through a certain angle, and are affected by the head and torso, which will produce attenuation of different frequencies and cause differences in front, back, up, and down directions).

WQ7034MX provides a way to expand two-channel stereo sound into virtual multi-channel sound through virtual surround algorithm processing, and then downmix it to stereo sound, making the sound field more open in terms of listening experience.

By simulating a theater space, the algorithm supports processing sounds from multiple directions and outputs stereo sound during music and movie playback. At the same time, it runs independently on the chip, does not limit the source APP, and supports Bluetooth devices on all platforms. After turning on the Spatial Audio function, the DSP only increases by 9 MCPS, and the power consumption increases by about 0.22 mA (based on the average of multiple measurements), which relatively increases the battery life and reduces the battery capacity.

Summarize

In recent years, with the development of TWS true wireless stereo headphones, OWS (Open-Ear Wireless Stereo) open headphones that focus more on comfortable experience have developed rapidly. However, this type of product currently has technical pain points and difficulties such as music leakage, call echo and wind noise, and battery life. In this regard, Synergy Shihui recommends the WQ7034MX Bluetooth SOC chip from Wuqi, which can greatly optimize such problems and has excellent features such as smaller memory space, lower power consumption, and richer expansion interfaces. Synergy Shihui will work with Wuqi to provide complete solutions and professional technical support for domestic and foreign manufacturers to help customers promote new products.