Got my Isurus in the mail today:
I've sold or broken every IEM I've ever owned except for the Monoprice 8320s, so I'll only be comparing against those.
Detailing is decent, definitely good for $20. The sibilance, though -- these are very hissy things, these things hiss much worse than any Beyerdynamic headphone I've ever heard! In some parts of songs, the sibilance just absolutely takes over the entire song at parts. I sadly have no other tips to swap in besides the provided tips, since IEMs just have not been my thing, but there's something definitely being very emphasized with the treble in the 5-8khz region. My biggest complaint is that the highs just don't work for me on songs where the sibilance is super apparent, if I can find a different set of tips I'll try them later, but the sibilance is a borderline deal breaker for me. One thing I noticed was that, even though the Tts had way more treble from those areas, the upper treble past 10khz was only a touch louder than the Monoprices -- the Monoprices brought out the odd high frequency touches that color Holiday by Swimming with Dolphins almost as much as the Tts. Right now, I honestly feel like the Monoprices only have a little less roll off the upper treble compared to the Tts. I honestly like the treble presentation of the Monoprices more than the Tt due to the lack of sibilance and similar amounts of upper treble, but I think the Tts had better definition of the highs.
Bass slam is definitely better than the Monoprice 8320. I feel like there's a decent mid-bass hump, but I really like the bass presentation on the whole. They can hit sub-bass frequencies pretty well -- I ran them through sinegen and it could hit 20hz. Very nice bass for the price. Overall, the bass is quick enough, quick enough to decently render Zabava by EnichKin's bass line. It's a runaway victory for the Tts for the bass.
Mids overall feel fuller than the Monoprices and more detailed. I feel like the mids falls behind the treble and bass, though, on the Tts and is more recessed. I don't have any real ground breaking things to say about this.
Solid isolation, better than the Monoprice 8320s. Soundstage is pretty good, but nothing to write home about, though. Cable is far less microphonic and less prone to tangling. If it wasn't for the sibilance issue I have with them, I'd mark the down for beating the Monoprices on every field, but those absolutely spoil the treble for me in some songs. For most songs, the Tts get my vote, but for the particularly sibilant ones I'd have to reach for the Monoprices.
I can't run these things out of my computer yet, because I broke my Fiio E6 somehow and I'm waiting on my O2 amp to get built and shipped -- the mid-bass hump is insane if I run them off of the computer.. Once that is done, I'll have some information about equalizing these things. Edit: For clarification, I've been driving them out of my iPod for now.
Just for grins, I also compared them against my Superlux HD681s -- as far as I'm concerned, those things and the Monoprices are the two best bang for your buck audio purchases I've ever made. Simply put, the $36 headphones beat the $20 Tts in pretty much across the board. I use the song "Be Calm" at 1:30 as my main test of instrument separation because it has so much going on during that part, and the Tts needed a pretty significant volume advantage for me to recognize all the sounds as well. The sizzling highs on cymbals or triangles sounded better defined on the Superluxes and their sibilance was not as bad as the Tts, but both had pretty high power brightness. The mids were definitely more recessed on the Superluxes, but I felt they won in overall mids clarity BARELY, although that was a pretty close fight -- if I were to test it more, I'm sure that would swing either way. It should come as no surprise that I felt the large headphone driver in the Superlux beat the large IEM driver in the Tts in bass impact.
With stock tips, I'd have to say that the Tts are a nice value at $20, but they weren't the absolute king of value that I expected, but they still get a recommendation from me. When you consider that the other things in the $20 bracket are the really cheap MEElecs and headphones like the Sennheiser HD202, the Tts look really good. Between the Monoprices and the Tts, I think it's hard to suggest the MEElec series of IEMs in the budget-fi bracket.