Apple continues to work on improving the sound quality of speakers, especially those on MacBook Pro or similar laptops. In a new patent application, the company describes how an audio track can be treated so that it seems to originate “elsewhere in an indoor outdoor space [rather] only directly from a speaker. “
“Audio signal processing for virtual audio can greatly improve a movie, even a sport, a video game or other screen viewing experience, adding to the feeling of being there,” Apple said in the request. No. 10,524,080, entitled “System for moving a virtual sound away from a listener using a crosstalk canceller.”
“Various known audio processing algorithms, executed by digital processors, modify one or more digital audio signals recorded, synthesized, mixed or otherwise produced”, he continues, so as to position a virtual source according to a modeling based on human perception of the sound, including the role of ear acoustics, other reflective and absorbent surfaces, distance and source angle, and other factors. “
While the majority of the literature describes laptop speakers, Apple claims that this patent covers virtual sound from any audio source, including headphones.
“In the case of headphones, specially processed audio signals (binaural rendering) are sent to the left and right ears of a listener without the crosstalk that is inevitably received by the ears when listening to stereo speakers” he says.
Apple says that by using “the cancellation of sound waves in the air surrounding the listener,” the audio can be controlled.
“For viewers and listeners who prefer the speakers, for example those which can be integrated in a portable computer, a crosstalk suppressor is used in certain virtual acoustic systems to produce sounds starting from several speakers of such so that for exle a “left” audio signal is mainly heard only in the listener’s left ear, and a “right” audio signal is mainly heard only in the listener’s right ear, “he says.
“This allows the left and right audio signals to contain spatial cues that allow virtual sound to be” positioned “at a desired location between the speakers.”
The six inventors credited with this work have close to 50 prior patents in related fields, mainly for Apple but also for Sennheiser Electronics. Martin E. Johnson alone has 38 prior patents, ranging from “correction of unknown audio content” to “Method and aparatis for estimating speaker distance”.
This latest patent, filed on December 31, 2019, follows two in November which aim to convert headphones to speakers and offer better sound insulation.
Apple has also recently filed a patent for headphones that can detect the ear they are placed on, which would affect how the left and right audio channels are routed.