Alright, since more than a couple of you guys is enjoying "power amp Alpha". I will go ahead and details what I have found.
Poweramp alpha solved 2 biggest problems within the Zx2: upper mid/lower trebles regions and slight background noises, these were not well played out in Stock player, disabled sound enhancement did bring them out to be better and more details. Onkyo Hf player app and Gonemad app also did bring these details out, but there would be some "background noises" for all of these above solutions. However, while we were stuck with it, Zx2 were still a good performer with TRRS anyways. Yet, I was still not quiet satisfied, and continue to seek for something better in these 2 reasons "lower-trebles energies, and background noises"
Voila, then I found Poweramp Alpha "this version is totally different than the one in the Google market place now" alpha is a test version but newest and being developed on. This alpha had new algorithms (audio engine). It captured my moments, attentions, right immediately, which none of the above apps did, and if you have notice...it took me a while to have found those solutions for the above "temporary fix". Yes, the lower-trebles energies were presenting, strongly, very defined, bold, and stand out....next up were the Insturments pace, each of the instruments now have an almost "perfect" pace, timing, and is well defined within each of their own space....next up were the soundstage, yes expansive and immersive, fully immerse me inside a "spherical scape" in a total 3rd dimensional of X-Y-Z and the flows of each effects running within this space is "fluid" and see no hesitation at all.
Better yet, I enabled my sound adjustment app, and turned on DSEE HX....my jaws dropped once again, this tiny, little, details of the lower-trebles energies and the instruments that dwell within this regions "pop" with "emotions" and "rhythm"...I am talking about those little hand shake devices, little hand held hi-hat and cymbals.....magically though, the "noises" that I heard before and was very ugly to me.....Gone! I told myself "what da fun ?" I thought these noises and slight "hiss" were from Zx2 "hardware" ? Perhap class D amp weakness ? but now it is gone !
In replacement of those noises were these beautiful "rhythm , details, clarity, tonal body, space" of these little instruments devices which lay within the lower treble spectrum and upper mid spectrum....these were messy before, and created these noises (were not properly decoded by the app). Luckily my Zx2 had no noises when plugged in headphones without playing anything, even if I open app, run apps on it....so I was very sure to myself that these were noises while playing music. Here I found the reason, and I found a solution for it.
Enjoy guys, this is the definitive solution to bring Zx2 into another level of musicality experiences: all the missing details you never heard before, or you thought it was lacking, the noises, the uses of DSEE HX technologies. Finally are all pieces and puzzled together. Again. Ironically....wasn't Sony who fixed it....but Poweramp team. I actually "smirked" as I realized how Sony had thought of this before about android, development of 3rd party apps, and they need not lifting a finger to improve their Zx2....lol...while other DAPs including Onkyo newest DP-X1 is not so friendly and welcome 3rd party app.
Check this post to get this app onto your Zx2, just over the air download and install it directly onto zx2...make sure to allow unknown sources by going to setting and check the box option
http://www.head-fi.org/t/742609/sony-nw-zx2-hi-end-dap/10080#post_12256619