To the OP, lets face some cold hard facts
(1) The quality of the audio medium varies widely - choose wisely ...
-- All mp3 or even mp3 360 quality recordings (compressed format) have a crap Resulting washed audio signature with a truncated rolled-off top-end and chopped off bass response from the crap file format compression. Sure .... They DO SUCK comparitively to CD quality at 16 bit / 44.1 kHz digital recording format .... or better. So go hi-Rez..,, full-stop.
(2) the quality of the audio player hardware and its build components
IiPhones only have an internal built-in crap quality "as-cheap-as-you-can-g0" internal DAC that is chewing gum price-build , so accordingly that intuitively dekuvers on,y very very low audio quality performer at best because it is produced at an ultra minimal component quality price-point in lockstep...
.pits just a mass marketed PHONE in stock form .... and it’s not any high-end player in stock form . It was never designed to be one and it won’t play hi-Rez so don’t expect it to produce above low-fi performance.
so mod the kit herein .... hence the workaround for hifi.
I suggest two things:
(A) Read more reviews in the first part , and then personally physically go audition the subject piece first to get a meaningful appreciation --pro or con -- before forming an biased opinion based on an uninformed pure hear-say experience.
To imply that the addition of a quality AQ microDAC / headphone amp is just more useless crap and somehow deliver only a sliver above a total suck-out in audio performance could not be farther from the truth .... the microDACs/ headphone amps (with quality-build cans or in-ear monitors) bridge the IPhone hardware shortfall nicely
The following us just a sampler of the many reviews with a common theme: the AQ and its whole genre work great performance wise and none of the reviews imply that the units still suck, Rather it is the opposite.http://www.wifihifi.ca/LatestNewsHeadlines/Hands-OnReview:AudioQuestDragonFlyBlack1.5/Red.htmlhttp://www.whathifi.com/audioquest/dragonfly-red/reviewhttp://www.stereophile.com/content/audioquest-dragonfly-red-black-usb-da-headphone-amplifiershttps://headmania.org/2016/10/05/audioquest-dragonfly-red-review/
Quality build Headphones - a bona fide critical necessity
You don’t want to wear brown shoes or $15 running shoes with a tuxedo . Scrap the crap quality 25-cent earbuds and bypass any temptation to fake it via the cheapo POS "gonna chintz it and try and fake it " kit
Gi invest in decent audiophile quality mobile headphones -- say .... roughly for discussion purposes .... at $400-ish and up ... (in-ear monitors, on-ear or over-ear) .... you only get what you pay for ... again full stop.
If you chintz it here, the rest of any improvements won’t get you to OZ. The degree of improvement will be an epic quantum leap .... full stop repeated.
MicroDac/ headphone amp -a bypass of the 25-Cent internal DAC in the iPhone is a BIG BIG audio performance upgrade
I have the AQ Dragonfly for my iPhone and my laptop and I also have a "higher" mobile headphone amp/ TEAC DAC (3X price of the AQ) . The latter is a bit better but they both sound and work great and the AQ is a marvel at its pricepoint .
Scrap the internal crap iPhone audio player app and go get a proper hi-Rez format player capable one
in order to play hi-Rez on an iPhone (it won’t in stock format ) it is important to bypass it and go get the ONKYO HF hi-Rez app player in the App Store...cheap at $14-ish. The player plays hi-Rez and even at a 24/96 file format medium with the external microDAC , it sounds impressive now.
the iPhone hardware shortcomings and like result from the POS cheap stock ear-buds or cheapo crap headphones form limitations using the iPhine as an audio player that "suck" in stock form
The limitations have been by-passed by quality add-ins and you can now play audiophile hi-Rez at 24/96 streaming on TIDAL or go download 25/96 and be prepared to be summarily impressed