The Dual Dynamic Drivers on the Blessing 3 are incredibly capable. Such a shame that they're not being put to good use, since the IEMs can actually handle a monstrous amount of additional sub bass, without any perceivable distortion (around an additional 6db of sub bass). Just fiddling around with wavelet, I was actually surprised the IEM could handle the default "bass boost" preset without any limiter. That's a bass shelf of around +6db on the sub bass, and absolutely no changes elsewhere. Why are they designing the drivers this way when they're not gunning for bassheads ? With this tuning, the Blessing 3 can outperform many of the bass focused IEMs in delivering clean and impactful bass, and yet the default tuning is the most conservative I have ever seen for a product of this class. All that additional bass is handled so beautifully on the Blessing 3 that it sounds like a completely different IEM. It is clean, rumbly, and doesn't cause excessive bloat on the other frequencies. Side note: for some reason, only using the IEMs wired and in legacy mode on wavelet produces distortion free sound. Enhanced session detection/running over bluetooth LDAC destroys bass completely.
Just because the driver is “capable” of it, doesn’t mean it’s ideal. There’s many reasons they might choose not to bump it up 6 or more dB. The consequences on the mids/highs get messy, the cost of components to compensate in the crossover can go up or become impractically large physically, the thd consequences can be substantial, the phasing related consequences of aggressive analogue filtering can cause audible artifacts, the list goes on.
Companies aren’t stupid, there’s a lot that goes into designing iems. Source: it’s a large part of my job. (Not at moondrop, unaffiliated)
Other than bass, is there any advantage to dual opposed 10mm drivers ? I know in the B3 they are responsible for low end but I have heard a similar low end in single DD setups. They must be doing something to be present, because the only other possible explanation I can think of is that they exist for the Blessing 3 dusk. I have seen a few tuned IEMs have very modest EQ enhancements like an additional 3 db bass, not extreme like 6db (except HBB & FatFreq) since it would not be to everyone's taste.
I wouldn’t assume theres always reason features are present, especially in audio where marketing hype and snake oil run so rampant. Like dipping all your screws in liquid nitrogen before assembling your speakers… lol. I’d say right now the biggest reason is just the hype train, that’s what’s in right now. From a technical perspective you get a little better power handling/output level without increasing thd. That’s essentially all, aside from it just being geometrically convenient to put them close together. As far as effects other than bass, there really aren’t any. One could argue that it makes the iem slightly more efficient because by acoustically increasing the output of the bass driver you don’t have to attenuate the high frequencies as much to get a bass shelf, but that’s not a huge improvement.
They could be leaving some headroom for the dusk as you mentioned, but I would argue there’s nothing meaningful outside of thd that a second dynamic would give you that you couldn’t pull off with a single. If that’s the case then that would be a small improvement to thd, but potentially a meaningful one.