From a Reddit thread on /r/audiophile, discussing HomePod:
They’re using some form of dynamic modeling, and likely also current sensing that allows them to have a p-p excursion of 20 mm in a 4″ driver. This is completely unheard of in the home market.
The practical upshot is that that 4″ driver can go louder than larger drivers, and with significantly less distortion. It’s also stuff you typically find in speakers with five-figure price tags (The Beolab 90 does this, and I also suspect that the Kii Three does). It’s a quantum leap over what a typical passive speaker does, and you don’t really even find it in higher-end powered speakers
The speaker uses six integrated beamforming microphones to probe the room dimensions, and alter its output so it sounds its best wherever it is placed in the room. It’ll know how large the room is, and where in the room it is placed.
The room correction applied after probing its own position isn’t simplistic DSP of frequency response, as the speaker has seven drivers that are used to create a beamforming speaker array,. so they can direct specific sound in specific directions. The only other speakers that do this is the Beolab 90, and Lexicon SL-1. The Beolab 90 is $85,000/pair, and no price tag is set for the Lexicon, but the expectation in the industry is “astronomical”.
Lots of people online are calling it overpriced because they think Apple just slapped a bunch of speakers in a circular configuration and added Siri, but the engineering behind it is extremely audiophile niche stuff. And it does this all automatically with no acoustical set up or technical know how.
One comment I’ve seen over and over is the fact that the HomePod is not stereo. From Apple’s official HomePod page:
Place HomePod anywhere in the room. It automatically analyzes the acoustics, adjusts the sound based on the speaker’s location, and separates the music into direct and ambient sound. Direct sound is beamed to the middle of the room, while ambient sound is diffused into left and right channels and bounced off the wall.
While you can add a second HomePod to get true stereo, there’s more going on here than simple mono sound. And I’ve long been used to Bluetooth speakers from high end companies such as Bose that fill a room with sound using a single speaker, frequently priced around $300.
To me, HomePod is a step up in audio quality and in functionality. Looking forward to February 9th. I’ll definitely let you know if it was money well spent.