Originally Posted by sdurani
It would be weird if the did the latter, since legacy soundtracks don't contain any intended height content.
There's the much-mentioned M&C footsteps, which by accident or design image overhead.
Speaking of the latter, why don't they just apply height cue processing like Atmos (see below) to 5.1 and 7.1?
Originally Posted by noah katz View Post
There's nothing I can see about the Atmos speakers that tries to get around the physics of speaker directivity, and all Andrew said in response to Scott's question about what prevents listeners from hearing the direct sound from the increasingly omnidirectional lower frequencies was that there's a "secret sauce" that NDA prohibited him from sharing.
My guess that this is processing yhe signal electronically with HRTF and/or the type of processing SRS and similar use to fool our ear/brains into hearing sounds come from directions other than where the speaker is.
If that's the case any speaker may work, but a coaxial would be best, the bigger the better to increase directivity down to lower freq.
Originally Posted by Roger Dressler
You have very good sense of the processing required. Here's how Dolby describes it in their patent application
In an embodiment, the adaptive audio system utilizes upward-firing drivers to provide the height element. In general, it has been shown that incorporating signal processing to introduce perceptual height cues into the audio signal being fed to the upward-firing drivers improves the positioning and perceived quality of the virtual height signal. For example, a parametric perceptual binaural hearing model has been developed to create a height cue filter, which when used to process audio being reproduced by an upward-firing driver, improves that perceived quality of the reproduction. In an embodiment, the height cue filter is derived from the both the physical speaker location (approximately level with the listener) and the reflected speaker location (above the listener). For the physical speaker location, a directional filter is determined based on a model of the outer ear (or pinna). An inverse of this filter is next determined and used to remove the height cues from the physical speaker. Next, for the reflected speaker location, a second directional filter is determined, using the same model of the outer ear. This filter is applied directly, essentially reproducing the cues the ear would receive if the sound were above the listener. In practice, these filters may be combined in a way that allows for a single filter that both (1) removes the height cue from the physical speaker location, and (2) inserts the height cue from the reflected speaker location.