So, whats the problem? I can tell you, some of us bought mx4 pro as music device because of high fidelity DAC from sabre - which is Sabre ES9018, and headphone amplifier from texas instruments - which is OPA1612 opamp. So it’s really good device if combined with pair of good headphones. Problem starts when you are using music streaming service, like spotify and tidal for example, or some third party apps like poweramp. And here are 2 kinds of people:
You may noticed, that music quality and power on headphones is significantly deacreased on those, compared to stock music player.
Thats because hifi feature is disabled on those apps, you are not using your sabre and amplifier anymore. There are some apps that can use hifi components on stock (besides flyme music player), like ttpod for example, but not too many. It’s probably set that way, because sabre+opamp drains more battery, but not much more i can say.
You are listening on earphones which doesn’t need too much amplification, and you didn’t noticed any difference. It does not mean you are deaf. Because as a alternative meizu is using wolfson wm8998 which is also very good dac - so sound quality is still amazing, and your earphones are driven correctly - so you don’t hear any lack of punch or something. But even there, you could noticed that hifi feature on phone settings doesn’t work at all. There is no difference if you change gain from low to high, or line out.
HIFI on kitkat works everywhere so there is no need to change anything,
but how do i enable it on lollipop? In any app that i want? —>
OFC you need to have root, and some root explorer.
Go to system -> etc -> audio_hifi.conf. Open it with text editor.
Here is your list, you just need to add your app on the list. You can find full names of apps in data -> app.
for example, spotify line should look that way: package com.spotify.music
Save and make sure that permissions of that file are 0664 (rw–r–r). If not, make them right.
Reboot your phone.