DOSS - SoundBox XL (Base Model)

I have this and it's quite capable. Bluetooth, 3.5 mm and micro SD card!! And the footprint is fairly small width/depth, it's just a little taller. https://www.amazon.com/dp/B071JN4FW6?ref=ppx_pop_mob_ap_share

https://a.co/d/hMdyQyE Ive used this but not sure if it would be too large for you 11.8"D x 2.64"W x 5.2"H. It fit in my small messenger bag. Sound is good and has a 3.5mm in the back and is currently on sale.

Denon envaya 150/200/250, Sony srs x55, x77, Harman Kardon Onyx 3,4, Xiaomi Sound Move, Créative Sound Blaster Road 2, Marshall Stockwell, Marshall Emberton 2, Harman Kardon Go + play (the one from 2016), Riva S, Riva Festival, Bose SoundLink Max, Bogasing S8 Pro Max, soundcore x600, Doss soundbox XL, Jambox, Sony srs xb33. I made "widest immersive stéréo imaging soundstage" one of my first point when i buy a speaker, and i like to try the most possible. they have all différents sizes, from différents years ,but all of them have insane soundstage with great stéréo separation for the size. Seems that older bluetooths speakers was better on point than recents ones (except for somes).

I’ve had the Doss Soundbox XL for years now. Awesome bass for the size/price of it.

Get a bigger speaker if you want "sub bass". I have a Motion + and it is great for it's size but not going to thump any sub woofer frequencies. The Soundcore Motion Boom/Select Pro put out much better bass. (I have a Mifa Wildbox that is very similar the soundcore Motion Boom in bass output). Had a few of the Soundcore Booms and they had great bass but it did not extend into the sub-bass region. Eons ago I had a compact Doss XL that Oluv was a big fan of and it had amazing low bass for the size but developed some rattles at high output and now living at work. I had heavyass Tribit Blast that could really rumble but at 12lbs was not that "portable". (Almost too much bass indoors !) Gave the Tribit Blast to a friend and going to try out the newer & cheaper and lighter Earfun Uboom X. Might want to check out the Harmon Kardon Studio speakers if you like the HIFI sound and from my memory did a grat job with sub-bass. I never grabbed a Uboom L because I had Motion + but I think most reviewers thought the bass was better and more extended on the U-boom L.

Nearly any decent Bluetooth speaker has stereo (or more) pairing now. I have experience with many speakers, but to name a few - some inexpensive Maio BT speakers that outclass far more expensive UE Boom speakers that I own, both do wireless stereo pairing. I also have a Doss soundbox that kills it in audio quality... no wireless pairing since it's like a stereo boombox, but I can expand it via aux cord. I also have an Edifier S300 which is big and boomy (but can be EQ'd nicely) and that also wirelessly stereo pairs. It does wifi streaming losslessly as well so points there. The point is there are tons of options now, some better than others but many can do stereo pairing so that compromise is mostly nullified. Many do wifi streaming and lossless codecs. The gap is narrowing.