Hi 10basetom
Your question regarding stereo separation and immersion when playing DVD are really at opposites to each other. The Playbase, Playbar and Beam are first designed for TV enhancement over its built-in speakers. The next step for those speakers is to build a DD5.1 (or any combination in between) Sonos home theater setup with those speakers handling L/C/R channels.
IMO the Playbar to fill a large room provides the best acoustic for TV enhancement performance. However, I find all three add a bit of coloration to music just by design (just as any other soundbar would IMHO). All three will perform to their best with a Sonos sub in the mix to handle the low-end. The differences between the Playbar and Playbase IMO are slight with the latter a consideration for space requirements.
The Beam IMO is not an option based on your room size. Although it is more feature rich than the Playbar and/or the Playbase which do not natively offer Airplay2, HDMI-ARC, Alexa voice assistant.
If you are looking for pure stereo separation (primarily for music) your choices are Play 5 , Sonos One (Gen1 & Gen2) and the Play:1. Each of those speakers would be purchased in pairs.
Here's the caveat...The Playbase, Playbar and Beam can be used for music but they will not produce the Stereo separation achieved by the Play 5 , Sonos One (Gen1 & Gen2) and the Play:1 in pairs. Also, the latter three cannot be mixed to create stereo pairs with the exception of the Sonos One (Gen1 & Gen2).
Click the link for a Sonos speaker comparison chart: https://en.community.sonos.com/what-to-get-228989/sonos-speaker-comparison-charts-6821929
Feel free to post back with additional questions. Cheers!
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