There are 7 tweeters in each Pod. Not only does a single Pod do stereo, it will analyse the surroundings to make use of walls etc to make wider stereo than it could just do by naively choosing a side speaker.
Stereo requires two horizontally displaced time-coherent sources. There is no other meaning.
If you're bouncing audio off walls you may get ambience, but you're not going to get a clean stereo image.
Also, the KEF speakers are hardly world beaters. They have a good reputation as PC speakers, but that's not setting the bar very high.
Professional speaker manufacturers like Genelec use a similar adaptive tuning system, and you can buy a microphone and software add-on to flatten the response of any speaker.
The limitations are well known. The correction curve is level-dependent, because room resonance is a time domain phenomenon created by physical standing waves in a 3D space that includes damping elements, and you can't truly correct it with a frequency domain solution.
You can approximate a time-domain correction with convolution and some assumptions about the room geometry and acoustics, but it's never going to be perfect.
Bottom line: I'm sure the Homepod sounds very nice, and - as usual - it's innovating with technology that's been available elsewhere for a while, and made much easier to use.
But it's not magic, and it's not going to sound hugely better than a much more expensive true stereo system.
Of course that'll do just fine for a lot of buyers.
"Stereophonic sound or, more commonly, stereo, is a method of sound reproduction that creates an illusion of multi-directional audible perspective. This is usually achieved by using two or more independent audio channels through a configuration of two or more loudspeakers (or stereo headphones) in such a way as to create the impression of sound heard from various directions, as in natural hearing.[1]"
I'm inferring from that there are other methods to create an illusion of multi-directional audible perspective.
So, I guess it determines which direction to use for the left and which for the right channel based on closeness to the wall. If so, what does it do when in the center of a symmetrical room? Is there a weird border case where it starts oscillating between multiple states?
If you're bouncing audio off walls you may get ambience, but you're not going to get a clean stereo image.
Also, the KEF speakers are hardly world beaters. They have a good reputation as PC speakers, but that's not setting the bar very high.
Professional speaker manufacturers like Genelec use a similar adaptive tuning system, and you can buy a microphone and software add-on to flatten the response of any speaker.
https://www.sonarworks.com/reference
The limitations are well known. The correction curve is level-dependent, because room resonance is a time domain phenomenon created by physical standing waves in a 3D space that includes damping elements, and you can't truly correct it with a frequency domain solution.
You can approximate a time-domain correction with convolution and some assumptions about the room geometry and acoustics, but it's never going to be perfect.
Bottom line: I'm sure the Homepod sounds very nice, and - as usual - it's innovating with technology that's been available elsewhere for a while, and made much easier to use.
But it's not magic, and it's not going to sound hugely better than a much more expensive true stereo system.
Of course that'll do just fine for a lot of buyers.