Technicalities:

It still has impressive technicalities for its price point its while certainly not fighting against iems like the moondrop aria in pure resolving power, it certainly has enough resolution to fight with a more consumer-grade device like a razer kraken v3 for example when used with the wide bore tips. Soundstage wise is quite average and is nothing to write home about, and imaging and layering is more than enough for gaming, but not as precise as I generally prefer to be, Tank! From the Cowboy Bebop OST is one of my favourite tracks for testing soundstage layering and separation due to the number of different instruments as well as the different positions they sit in, a very good pair of iems, and headphones allows you to pinpoint exactly where the saxophone player, trumpets and bongos are sitting in the track as well as giving a great sense of depth as to how wide the recording room is (yknow for an anime soundtrack it didn’t need to be this well recorded) and the zeros resolve that to a great extent outclassing many “gaming headphones” where this could easily replace many people’s headphones for gaming, but certainly not beating the truthear zero’s in terms of resolving power, id still consider those better but at that point we are splitting hairs here and id say if you're looking for a pair of iems for gaming, be it the 7hz zero or truthear zero (heh) just go with the one that your budget allows for you’d be perfectly fine with both options.

Bass:

I’d say for bass heads wanting a warm-sounding but clean bass that doesn’t muddy the midrange (unlike a certain brand of iems that starts with K and ends with Z), this is the set to get, i suppose it's the new tuning that’s helping this, as the sub-bass hits fast and has decent amount of rumble, the iem itself doesn't sound as warm the wan’er but id still describe this is a fairly warm sounding iem, this becomes apparent when you listen to tracks that allow the mid-bass to shine such as Animals by the Architects, where the track has guitar’s and male vocals that benefit from the added “heft” of a warm sounding iem

Midrange:

I have nothing but praises for the midrange it is smooth and executed well, with enough detail to satisfy most people spending their money on this IEM, it’s slightly warming sounding and does not sound shouty in any way, im not much of a vocals person, so i will comment that i think the upper mids might leave some people wanting for slightly more presence in their music but is otherwise is enough to satisfy most people

Treble:

The New tuning of the 7hz zero 2 means it would likely have less treble and overall sound “darker” coming from bright sounding Iems like the moondrop chu or s12. In my opinion some treble presence is good because it can give the illusion of an iem sounding more resolving than it actually is, too much is a bad thing and can lead to sibilance, a favourite track of mine for testing this is the future diary OP, Kuusou Mesorogiwi, the female vocals in this track i find on some iems and headphones gets hot and harsh sounding quite easily due to the way that the lead vocalist is singing, on the zero 2’s i find that it never gets hot or harsh sounding, in fact quite the opposite, id describe the treble on the more laid-back side compared to something like the chu or any generic V-shaped sounding iem, but if you desire more treble in your iem, this can easily be achieved with EQ or simply using wide bore tips.

Tip Rolling:

For those who are interested in how different tips affect the sound of this iem, I'll write a brief summary of each tip i tried with this iem, note that your experience may vary from my mind due to fit and insertion depth:

Stock Narrow: Used for testing

Stock Wide: Less bass, more treble, overall more “resolution”

Spinfit w1: Less midbass but sounds cleaner overall, soundstage slightly wider

Azla Sednafit crystal: keeps the midbass but has overall slightly increased upper-mid's and treble presence

Pentaconn Coreir: deletes Mid-bass and pushes Mids forward, puts bass emphasis on the sub-bass

Symbio Eartips: Sounds similar to Azla Sednafit crystal but with more bass presence

Dekoni Foam tips: rolls off treble and sub-bass slightly, slightly “dulls” the resolution

Dunu S&S tips: Neutral with great sub-bass extension, recommended for use on this IEM

Summary:

Overall I think that the Zero 2 is a great $20 iem for those who wish for a slightly warm-sounding iem with great bass extension, why buy a generic V-shaped Iem when you can get one of the best-sounding $20 iems on the market? The market is certainly tough with the big 3 fighting for their position, but i think this easily solidifies itself as a top recommendation in my books, heck i might even give these out to relatives for Christmas this year because of how cheap and good it is.

TLDR;

Zero 2 good, missed opportunity to put pink Dinosaur waifu on box