All the assets shared by other posters agree that there are NO woofers in the second row doors. In the overhead view diagram with the red lettered speaker locations, the woofers are the D size in the front door. In the part number schematic shows clearly the big speaker in the second row is only for the '10SP' option. There is no part identified for that spot in the 21SP config. This is clearly the physical design for some reason, but good grief, it does seem like a terrible design choice. I've got a little north of 3K miles on my OT+, and don't really notice an improvement after breaking-in. This system does sound better than my 2017 4runner, but I attribute a lot of that to the dramatically quieter cabin. I'd say it sounds on par with my wife's 2018 Sienna system....fine, but nothing like premium, and definitely not like a paid upgrade.
The fact that there have been recommendations to disable features to improve the sound does seem to point to a software problem that might be addressable in an update though. I don't notice much quality difference with surround sound and auto-sound-leveling turned off though personally. I also don't notice much difference between surround sound being on and off just in general. The presence of a 'surround sound' option at all make it seem like the system should be able to handle Apple's Spatial Audio, or dolby's atmos, or some kind of surround input, but I can't hear it if that is what's happening.
Def bummed out by this aspect of the vehicle, and hope there's something that can be done in a software update. Eager to hear what
georgeciobanu finds out