So did some more listening to my Mavin Air-XR.
They are a slightly L-shaped signature, quality bass and it reaches deep. Fortunately it is not muddy sounding and does not bleed into the mids. Despite the slightly elevated bass quantity, it is quality and enjoyable. I prefer a more balanced signature and after burn in, this is very good. The mids and highs are also very good and aren't too far back due to the slightly elevated bass, no sibilance and vocals are good.
The overall detail and sound is a good step ahead of the Tronsmart Spunky Beats. Battery life for me is around 5.5-6hrs APT-X, 6hrs AAC & SBC on an Android phone.
I also got some foam tips that fit correctly, as I prefer foam and fortunately they fit the case too.
Link's here:
https://www.head-fi.org/threads/best-iem-tips.626895/post-15454166
Note: I do use EQ and bring 31/62hz -4db and 125hz -2db and that makes them keepers for me.
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Also I've done some mods on my X12 Pro's, figured I'd share here.
I reshaped my X12 pro's for a better fit (for me), using a file. Hard to photograph but I kind of un-shroud the main opening and give it a larger radius. This lets it sit a little more forward and takes enough pressure off that I'm no longer feeling a hotspot in my ear canals. I also use a small razor around the small openings to give it a bevel.
I previously posted this but I do use them with earbud foams that I mod with a hole I make using a 3mm punch. Keeps more bass in and makes it a more stable fit, without needing to use the provided 'wings' that do not fit the charging case. The foams do fit fine in the case, just have to lightly press the earpieces into place.
I spent some time today modding my 'brand-used' X12 Pro case with the Qi wireless charger taken from a bad E12 set.
The X12 & E12 have different circuit boards and retainers as the charging posts are aligned differently. You can't use an X12 in an E12 case and vise versa.
Once I had the cases apart I saw the circuit board had the input provision to for the wireless charger.
It was necessary to remove the original thicker double sided foam from between the battery and circuit board holder. That was replaced with 3m double sided foam, the automotive stuff that is grey. I actually stretch it so it's thinner as well.
To fit everything I filed the bottom of the cupped areas that the earbuds point down into for a little more room inside.
The Qi coil from the E12 also uses a thicker double sided black foam, which I replaced with the stretched grey 3m stuff as well. The E12 case has more room inside as the cups are not as deep. No idea why as the X12 is a much shallower fit.