Apple has been granted a patent (number 10,264,383) for a “multi-listener stereo image array” that hints at what I like to call the HomePod Theater — a high end (higher end?) HomePod designed as a sound system for use with an HDTV.
In the patent filing, Apple notes that stereo sound system drivers are often positioned with respect to a design position of the listener, so that a driver configured to provide a “left” channel is positioned to the listener’s left, and another driver configured to provide a “right” channel is positioned to the listener’s right.
Collectively the drivers can provide a virtual stereo sound stage, or “stereo image,”for the listener where the listener can perceive certain sounds as emanating from various directions, including from virtual sound sources. Sounds intended to be heard from the left end of the sound stage can be preferentially provided via a left driver, so that the listener perceives the sounds as emanating from a sound source to the left of the listener, and sounds intended to be heard from the right end of the sound stage can be preferentially provided via a right driver, so that the listener perceives the sounds as emanating from a sound source to the right of the listener.
What’s more, sounds intended to be heard from the center of the sound stage can be provided equally via both a right and left driver, so that the listener perceives the sounds as emanating from a virtual sound source positioned between the drivers.
However, in some cases, a listener is not positioned symmetrically between two drivers that are configured to provide a stereo experience. As a result, the listener may perceive sounds generated by one driver more intensely and earlier, relative to sounds generated by another driver, and the stereo sound stage experience can be less than ideal. Such positioning can further occur where multiple listeners are positioned to receive audio content from a stereo sound stage system.
Apple says that because at least one of the listeners may not be positioned symmetrically relative to all of the drivers providing the stereo sound stage experience, the listener’s experience of the stereo sound stage “can be less than ideal.” The company wants to change this.
Here’s Apple’s summary of the invention: “Some embodiments provide a multi-listener stereo image array which provides multiple separate stereo images of audio content to each of multiple listeners while mitigating interference of audio signals which provide separate stereo images to separate listeners.
“The array can include sensors which can monitor the environment and can identify relative positions of various listeners and can further control the audio signal patterns generated by the drivers of the array to propagate towards positions associated with particular listeners and be at least partially restricted from propagating towards positions associated with other listeners.”
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.