Because laptop speakers are so close to each other, they can’t deliver the stereo that consumers are increasingly accustomed to. Apple’s patent covered a virtual acoustic audio system that’s supposed to address that issue. Rather than simply emitting sound from its speakers, a MacBook equipped with this technology would be able to make it seem like the sound came from elsewhere. Apple said in the filing:
“A virtual acoustic system is one that gives the user the illusion that sound is emanating from elsewhere in an indoor or outdoor space than directly from a loudspeaker (e.g., one that is placed in a room, one that is built into a laptop computer, etc. Audio signal processing for virtual acoustics can greatly enhance a movie, a sports even, a videogame or other screen viewing experience, adding to the feeling of “being there”. Various known audio processing algorithms, executed by digital processors, modify one or more recorded, synthesized, mixed or otherwise produced digital audio signals in such a way as to position a virtual source according to modeling that is based on human perception of sound, including the role of ear acoustics, other reflecting and absorbing surfaces, distance and angle of source, and other factors.”
Apple goes on to say its virtual acoustic audio system will use a crosstalk canceler and multiple audio signals:
“A processor-based method of audio processing, comprising: splitting an audio signal, representing a virtual sound source, to a first processing path, a second processing path and a third processing path; in the first processing path, operating with a direct gain and a direct virtual source algorithm on the audio signal in the first processing path; in the second processing path, operating with a plurality of early reflection gains on the audio signal in the second processing path and producing a plurality of early reflections respectively, each having an adjustable delay, and processing the plurality of early reflections according to an early reflections virtual source algorithm; in the third processing path, operating with a reverb gain and binaural reverb filters on the audio signal in the third processing path, and crosstalk canceling upon outputs of the binaural reverb filters; and combining left and right channel outputs of each of the first, second and third processing paths, to produce a left loudspeaker signal and a right loudspeaker signal.”
The patent covered numerous configurations of this virtual acoustic system that change how the crosstalk canceler is used–or if it’s used at all–and how each of the paths are utilized. Check out the patent for more information on how Apple conceived of the system and what forms it might take in a real product.
Apple filed the patent application, titled “System to move a virtual sound away from a listener using a crosstalk canceler,” in August 2018. USPTO granted the patent on New Year’s Eve. That means it could be a while before this system appears in a MacBook–assuming that Apple plans to continue developing it at all.