Actually since I noticed I had bunch of dumpers I decided to remove the stock one, it had 2 layers of dumper, one layer of fabric(paper-tape-like) filter and, another very congested small and conjested iron dumper, I basically find those iron with small outlets unjustifiable for acoustic tuning, so I removed.
OK, trebles got bit boost, but as the nature of pure-beryllium (light thin and elastic), treble boost doesn’t bother my ear, not like those BA or CNT dynamic driver’s screams. bass floor is lowered with more “direct raw sound”. I feel I need a bit more bass, so I may play with some tips/cables/dumpers.
[update]
added moondrop Starfield dumper filter.
Slightly better and cleaner than original, bass still sounds foggy 🌫.
will switch dump filter to find a better match.
Moondrop blessing2 filter:
Yes, only a slightest treble tame + bass floor raise, by only tiny bit. I will settle with this dumper
Final settlement: XELASTEC L & raw nozzle
Tried various tips, foams, final E, spiral dots, spinfits, UM, bass boost, all sort of tips and concluded for LCP & pure beryllium, AZLA xelastec works the best in taking maximum benefit of those drivers. The bass is uninterrupted, yet slightly lacking the quantity to my liking but I can live with this level of KBEar Lark level of almost flat bass.
Guitar picking and bass slapping is one of the best sounding on Believe, “elastic “ is an appropriate word I can think of , it bounced well with speed and punch, which BA drivers has the speed but no punch, other dynamic drivers has the punch but it blows slow. I found LCP drivers such as Moondrop Aria is more leaning toward CNT side, and Believe’s pure-Beryllium is toward BA side of tonality, means pure-beryllium has higher resolution and speed. Not huge but distinguishable one.