Improving audio is obviously on the collective mind at Apple. Following the granting of a patent that hints at iMacs and Thunderbolt Displays with surround sound, the tech giant has filed for a patent (number 20170230772) regarding a method for “creating a virtual acoustic system with an undistorted acoustic center.”
Apple says the invention could involve such audio sources as a desktop computer, a laptop computer, a tablet computer, a home theater receiver, a television, a set-top box, a personal video player, a DVD player, a Blu-ray player, a gaming system, and/or a mobile device (e.g., a smartphone).
In the patent filing, Apple notes that a single loudspeaker may create sound at both ears of a listener. For example, a loudspeaker on the left side of a listener will still generate some sound at the right ear of the listener along with sound, as intended, at the left ear of the listener. The objective of a crosstalk canceler is to allow production of sound from a corresponding loudspeaker at one of the listener's ears without generating sound at the other ear.
This isolation allows any arbitrary sound to be generated at one ear without bleeding to the other ear. Controlling sound at each ear independently can be used to create the impression that the sound is coming from a location away from the physical loudspeaker (i.e., a virtual loudspeaker/sound source).
Here’s Apple’s (tech speak-heavy) summary of the invention: “A system and method are described for transforming stereo signals into mid and side components xm and xs to apply processing to only the side-component xs and avoid processing the mid-component. By avoiding alteration to the mid-component XM, the system and method may reduce the effects of ill-conditioning, such as coloration that may be caused by processing a problematic mid component x.sub.M while still performing crosstalk cancellation and/or generating virtual sound sources. Additional processing may be separately applied to the mid and side components x.sub.M and xs and/or particular frequency bands of the original stereo signals to further reduce ill-conditioning.”
Of course, Apple files for — and is granted — lots of patents by the U.S. Patent & Trademark Office. Many are for inventions that never see the light of day. However, you never can tell which ones will materialize in a real product.