Fraunhofer Cingo®

An immersive listening experience for mobile devices

With Fraunhofer Cingo®, your mobile devices become true multidimensional sound theaters. Plug in your earphones or use the built-in stereo speakers for enveloping surround sound and 3D audio when enjoying your movies or music library.

But Cingo does more than enable an excellent surround sound listening experience over stereo speakers or headphones; it also provides existing stereo content with a more natural, clearer sound, and includes loudness optimization for listening in noisy environments. In addition to the existing stereo or surround content, Fraunhofer Cingo supports rendering of 3D audio content with formats that add a height dimension to the sound image.

Due to this unique combination of latest developments in audio technology, Fraunhofer Cingo delivers an exceptional level of audio quality, unmatched on mobile devices.

The powerful and innovative underlying signal processing was developed by the audio experts at Fraunhofer IIS, the home of mp3 and AAC.

How Cingo works

On its way from the loudspeakers to our ears, sound is altered in several important ways. By the time it reaches us, it contains information about the listening environment as well as the actual musical or speech content. In addition, sound waves that arrive from different directions are shaped by our head and outer ear. Collectively, this information helps us to identify the distance and direction of a sound source.

When using headphones, this information is absent because the audio content is played back almost directly at our eardrums and therefore appears as if the sound is 'in' our head. This can lead to considerable discomfort during extended periods of listening.

But researchers have discovered that these changes in sound waves can be measured and modelled by digital filters. By applying those filters to audio signals when listening on small devices or headphones, we can achieve a spatial sound impression close to the one achieved with 'real' loudspeaker playback. This technology is called binaural audio processing and is just one feature of Fraunhofer Cingo.

Fraunhofer Cingo creates an immersive surround sound experience reminiscent of the one we all know and love from the cinema. Flexible and convenient, the technology works with any pair of regular headphones or built-in stereo speakers.


Virtual surround sound for headphones

With Cingo, each audio channel can be presented as a virtual sound source, for instance as a loudspeaker in a listening room, in such a way that it is heard from a specific location and distance. The sound appears to come from “outside the head” and from outside the headphones. As a result, when using Cingo, the listener is always sitting in the sweet spot.


Virtual surround sound for stereo loudspeakers

Dedicated speaker processing enables the virtual surround feature even when sound is played back over stereo loudspeakers, such as from a laptop, tablet or larger smartphone. In these instances, the sound appears to come from outside the device and feels bigger and more spatial. The result is an engaging and compelling immersive experience that brings the listener completely into the acoustic environment.

Head tracking

More and more smartphones, tablets and headphones have built-in sensors to determine the listener’s head position. With the help of this sensor data, Cingo can dynamically and efficiently adjust the acoustic space so that the sound image doesn’t rotate when the listener’s head turns, but remains stable just as it would in real life. As a result, the sound image adapts naturally to the listener’s head orientation, significantly improving the 3D feeling and spatial precision.

Loudness optimization

Within a noisy environment, such as the subway or a bus, or with devices where the loudspeakers or headphones simply cannot output sufficient volume, loudness processing can be tremendously beneficial. The loudness optimization feature of Cingo delivers a natural and clear sound even in the most challenging situations while preventing unpleasant distortion or any clipping which would lead to reduced audio quality. It is particularly useful for content that is very soft or of high dynamic range.


Device-specific equalization

The quality of headphones and loudspeakers can significantly limit the user’s audio experience.The equalization feature of Cingo, compensates for the lack of bass usually encountered with smartphones and tablets, and corrects any unpleasant resonance frequencies by optimizing your audio on-the-move. The innovative techniques involved were developed by studying and measuring the performance of a variety of different headphone models and loudspeakers on mobile devices.

3D immersive audio

In addition to the existing stereo or surround content, Fraunhofer Cingo supports rendering of 3D audio content with formats that add a height dimension to the sound image, such as 5.1+4 and 7.1+4. It even provides the option of placing an arbitrary number of sound objects anywhere in a virtual space around the listener. As a result, the listener can perceive sound elements in the front, behind, from above or below, and be truly immersed in a movie or a musical piece. The stunning level of reality creates an experience of “being there”.

MPEG-H Audio support

Cingo works with all channel-based formats, from stereo and 5.1 surround to immersive formats such as 5.1+4 or 7.1+4. It also supports direct rendering of audio objects with associated position metadata such as azimuth, elevation, distance and spread.

All necessary channel and object metadata can be transmitted using a modern codec, such as MPEG-H Audio. Thanks to close cooperation with the codec developers, the Cingo–MPEG-H Audio decoder interfaces for this metadata have been engineered to optimize the sound experience for MPEG-H content on mobile devices.


Where to experience Cingo

Original equipment manufacturers


Cingo has been integrated into the built in Fire TV operating system of the Rear Seat Entertainment Experience, which is now available across all models of the BMW 7 Series. 

Cingo provides headphone playback of stereo and 5.1 surround sound for streamed content on apps like Amazon Prime, Hulu, Netflix and YouTube.

Google Fraunhofer Cingo delivers an unrivaled surround sound experience to the users of the Nexus and Pixel device family.

Service providers

Youku The Chinese video hosting service provides premium users with compelling and immersive sound on iOS and Android – all thanks to Cingo.


Cingo‘s floating- and fixed-point libraries are available for mobile (iOS, Android) and desktop (Windows, Mac, Linux) platforms, as well as embedded Audio DSP platforms. Thanks to its minimal resource footprint and an optimized fixed-point version, the algorithm even runs on established headphone processors.
Available for popular audio development platforms for a seamless embedded integration. A custom platform integration can be realized upon request.

OS integration

For device manufacturers, integrating Cingo into an operating system, such as in an available media framework, is the recommended integration method. Depending on the device target platform, there are implementations available through one of our partners or through Fraunhofer directly.

App integration

Content service providers can use Cingo by directly integrating it into their client applications. Direct integration of Cingo is possible both for applications that use natively available player architecture (extractors, decoders, etc.) as well as player applications that service providers have developed in-house.

Headphone DSP integration

Cingo can render spatial audio directly on established headphone DSP's (Digital Signal Processor). This reduces head-tracking latency even below perceivable thresholds and independent of wireless transmission latency. It enables manufacturers to deliver dynamic spatial audio that works consistently across any audio source device.

More Information

Interested in Cingo?

To learn how we can adapt the Cingo software to your needs, as well as to obtain licensing information:

Video: Introducing Fraunhofer Cingo®

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