MobiSound is a set of digital audio manipulation and enhancement algorithms based on the theories of 3-dimensional spatial audio processing and human hearing/psychoacoustics.

MobiSound is specially designed for mobile devices to restore the natural sound by relieving the physical constraints imposed by headphones and loudspeakers on sound reproduction. These physical constraints include closely-spaced loudspeakers; headphone pressed at the ears; sound intensity limitation; low-frequency loss of small speakers; and mono or stereo recording of 3-dimensional sound events.

MobiSound currently consists of WideSound, OpenSound, DynaBass and MotionSound (More component technologies to be added.) Depending on applications and playback means (loudspeakers or headphone), different component technologies can be combined. Common features of MobiSound technologies are:

• Audio input: mono or stereo audio signal.
• Audio output: 2-channel audio signal (DynaBass applies to 1- or 2-channel output.)
• Sampling rates: 8/10/11.025/12/16/22.05/32/44.1/48 KHz.
• I/O format: 16 bit/sample linear PCM.
• Reference C code: 16-bit integer C code.

WideSound [for stereo loudspeakers]

WideSound broadens the sound field produced by closely-spaced speakers to much wider for significantly better stereophonic effect, while still preserving the clarity of vocals and dialogue. WideSound is especially useful for presenting spatially-dynamic audio contents such as from games, movies, TV or live broadcast. WideSound works even for extremely narrow speaker spacing, e.g., 2cm center-to-center for mobile phones.

WideSound allows user to optimize sound widening effect for specific applications, from mobilephone to home TV. This is achieved by user-controllable parameters - distance between speakers; distance from user to speakers; and desired widening angle.

To illustrate WideSound effect, a small device shown in the picture below would have produced narrow-field sound, but with WideSound, it would produce wide-field sound like the audio signals actually come from two wide-spaced speakers on both sides of the small device.

WideSound applications include game devices, portable DVD player, mobile phones, MP3/MP4/PMP players, laptop/netbook PCs, portable TV/automobile TV/home TV, LCD monitors with stereo speakers, AV display/advertisement, picture/video frames, HD radio, learning devices, etc.

Technical specifications: With stereo audio input, at 44.1KHz sample rate, MIPS=10.6, RAM=4KB, ROM (data)=0.8KB. At 16KHz sample rate, MIPS=3.25, RAM=2.6KB, ROM (data)=0.8KB.

OpenSound [for stereo headphone]

OpenSound converts plain audio signal into rich, immersive sound with significantly wider perceived sound field. OpenSound manipulates the headphone sound so that even if the sound is played with the headphone pressed at the ears, the listener's perception is as if the sound comes from virtual speakers away from the ears. OpenSound creates wider-field and immersive sound (as shown by the spherical sound zone below,) and reduces listening fatigue by relieving headphone oppression for much more comfortable, relaxed listening.

OpenSound applications include MP3/MP4/PMP players, mobile phone/smart phone/PDA, stereo Bluetooth headset, laptop/netbook PCs, portable DVD players, game devices, learning devices, mobile TV, and so on.

Technical specifications: With stereo audio input, at 44.1KHz sample rate, MIPS=9.5, RAM=4.4KB, ROM (data)=0.6KB. At 16KHz sample rate, MIPS=3.2, RAM=2.8KB, ROM (data)=0.6KB.

DynaBass [for mono or stereo headphone/loudspeakers]

DynaBass dynamically generates "virtual" bass signal to significantly enhance bass perception for micro-speakers typically used in handheld devices. These small speakers lack low-frequency gains and that cannot be corrected by simple power-boosting of the low-frequency spectrum. DynaBass enhance bass perception without increasing power consumption.

MotionSound [for stereo headphone/loudspeakers]

MotionSound renders dynamic, moving audio scenes that emulate a real three-dimensional sound environment. The audio scene can be pre-determined by following a script or the audio scene can change dynamically as event-triggered (such as by user's input or game logic in a video game). By placing stationary sound segments in any time sequence, sequentially or simultaneously, at any position or on a trajectory in the 3D space around a listener's head, MotionSound is able to create very interesting perceptual effect.

MotionSound applications include interactive games, educational devices, children books, virtual tours, 3D audio presentation, and other 3D virtual reality applications.