I wasn't going to write, because I simply lack knowledge, but since you apparently got a lot of motoring replies instead of information, then I guess I might try and throw in something which could be (perhaps? maybe?) somewhat relevant or at least entertain more knowledgeable people with my foolery.

I don't know if those serrations are like that, but in loudspeakers membrane can be ribbed which is done in order to delay distortion on that specific part. With increase of power membrane will start distorting, but it is not distorting whole, rather certain areas which are responsible for different frequencies start distorting earlier while some later. As such you can increase power handling of the membrane by ribbing it, even just partially. Tonally ribbed membrane is usually darker, while straight/smooth of the same material and dimensions is brighter. However membranes can be made of different materials, for example paper or kapton, and aside size can have different thickness, density, stiffness, they can be soaked or coated in some additional substances, and all will affect both sound as well as power handling properties.

The diagonal angling of those serrations actually look like it might be used to stop the wave from traveling along the membrane, something like wing fences on Mig-15 :P If I recall it right the sound actually travels along the ridge of the speaker and even come to play with the baffle.

Headphone drivers are mystery for me as well, the fight is against the size limitations so there is a lot of witchery like this going on.

Indeed, my bad - its PCM1794 instead of CS4398.

Although personally usually I can't identify chips by sound differences nor tell if the difference is in the chip or implementation of it. The Z is the first time since I've stopped using X-Fi where everything sounds properly, flat/no issues with tonality. I did look for ZxR prior, but it is a hard find, and I just came across Z for $39 from a friend. I do like it to the point Ive stopped feeling like I need to upgrade/buy something further... and I do feel like I wasted time and money with all those external solutions.

Sound Blaster Z > G6

I actually switched to Z from G6 just recently, such an improvement. The Z and ZxR differentiate in amp with ZxR using TPA6120 instead of JRC 2114. The chips configuration of ZxR is actually similar to my FX-Audio X6.

Only Z combined with an amp made my current production HD600 enjoyable. Neither G6, X6 or cheap dongles managed that.

The soundstage is bigger than in more direct sounding earphones like Vido, Monk+, KBear Stellar or EMX500, but not extremely big. It actually is similar in size to Snow-Lotus 1.0, but like with a tiny bit of reverb added so it sounds more spacious than it. Reverb/echo is not a soundstage, it will sound spacious, but instruments/soundsources can't be placed there. As for positioning sounds in space I personally found everything mentioned above to be about the same. Like there is no actual difference in accuracy if you try to locate a sound source in 3D gaming. They all do 360 somewhat ok, but all fail at distance.

Paiaudio PR1 does improve that, despite it being slightly warmer and lacking in details, the soundstage is fairly big, and more accurate, you can tell which room say enemy in fps is, but accuracy is still like within several meters, so you can't tell where exactly in that room, can't just fire at specific spot.

Currently I'm trying out Qigom S300 White Lotus, it does sound most spacious, I think it has the biggest soundstage + a bit of that reverb. It is the most accurate when it comes to distance as well. Sorry for using gaming as example, but in their case I can play more or less normally, get a good grasp on distance on sounds that are gradually closing in to get a good timing when to react/prefire and such. It is not yet a tournament grade, not on par with good more expensive headphones, not a wallhack, but first among the budget earphones where I don't feel like I'm really being hold back.

I'm recommending cheap FAAEALs almost everyday :P

Personally I like FAAEAL Snow-Lotus 1.0 more (also have SPC version, no difference), because I find Rosemary's treble to be a bit piercing and fatiguing, although Rosemary is killing it when it comes to details in the price range. Snow-Lotus is a bit calmer, slightly less reverberating, if there is a space between the sounds it feels completely empty. So I kind of like them as a daily driver at PC, next to HD600.

Aside that I'm using Iris Ancestor as a headset for mobile, I do have Iris 2.0, it's the same sound, I like 3 button remote of 2.0 more, but simple straight cable of Ancestor more :P

btw. recently been discovering Qigom S300 White Lotus (300Ohm 109dB/mW). It sounds bright, but not piercing and is not fatiguing, so I just started listening to them and got used to it. Soundstage might be the best for the price, not just bigger than Paiaudio PR1, but also better imagining when it comes to distance. They are currently my choice for comfortable fps gaming (but they are not "tournament grade"). One qualm though, they are particularly good with Sevenhertz 71 (AK4377), but with CX-Pro CX31993 I did feel some fatigue - it is just that one dongle, all the other sources I have are fine. There is also S300 Black Lotus which is said to be more balanced version, so I'm thinking about testing it as well.

HD555, HD558, HD595, HD598, HD599, HD600 and more

In the price range crappy SR850 or actually good, used HD430. Even some gaming headsets like crap from Plantronics.

Cheaper I guess even crappy Koss KPH7 which plays with only a narrow band of midrange or, I'm even scared to mention, boxy sounding $3 Shini S-520 seem better. Koss Porta Pro might be the worst one I have ever owned in that regard, although for just "tried" there might be some competition (HD201, Barracuda HP1, cheapest circumaural Philips).

Not to mention earphones, not only cheaper Qigom S300 White Lotus or Paiaudio PR1 destroy it, but even $9 FAAEAL Snow-Lotus 1.0 or $6 Iris Ancestor.

I will give Koss Porta Pro a really nice velvety low end which is usually unavailable for the price, and also low clamp force, but thats it (well treble are actually quite decent when there isn't anything else to interfere), certainly not imagining or soundstage.

I don't know about KSC75, but Koss Porta Pro are beyond bad when it comes to soundstage and imagining :P

I have another ones, angled, for like $59 or $69 in like 2007. Felt like they were very overpriced and didn't sound better than cheap ones. I might try them again if I find a missing tip somewhere (unless it was eaten by a vacuum :P). Their cable was deteriorating the sound though, it was detachable for splitter mounted 3.5mm so I tried using it as an extender for Sennheiser earphones and found that out, but I guess this also mean I can just use another one.

There are 2 small issues here.

1st is whether you actually have ALC1200 or ALC1220 as there is a big difference between them. ALC1200 is capable of only 1V 30mW at 32Ohm, while ALC1220 is capable of 2V (don't know the power).

2nd is the MSI implementation of it. My MSI Z690-A has only 3.2mW out of ALC897 (a $229 board with low end chip...) and it has 80Ohm output impedance at that. I don't know how powerful the ALC897 can get, but certainly that board is much quieter than than my other Gigabyte board using ALC892 (the same chip, ALC897 is a refresh). I recall multiple posts of people at HeadphoneAdvice complaining on low output of their MSI onboards, at least 2 of MAG Mortart series on B series AMD chipsets.

That said DT770 are an entry level closed backs and you simply might not like their sound.