Always, much better than Dolby, AudioFX and others that I tested.
The "codecs" most important is DDC/Kernel (.vdc and .irs).
When I install them in 2019 liked ClearPlus HD.irs and V4ARISE.vdc.
It's a little hard to set up (Viper and set presets) but when you learn is easy do the same for all headphones.
Maybe it could help.
I recommend you remove that older process installation because you don't need to change SELinux from Enforcing to Permissive (insecure).
In Magisk
1. Install Audio Compatibility Patch (v2.3)
2. Options: Yes, Up, Yes, Up, Yes, No, Reboot.
3. Install Audio Modification Library (v4.0), reboot.
4. Install Viper4Android FX v2.7.2.1 (driver v2.5.0.4)
NOTE: Viper FX will install the latest app, finish installing Driver v2.5.0.4 on it and running (do some test to confirm).
Afterwards, remove the latest app and install the v2.6.0.6 app.
Install Viper4Android FX app (v2.6.0.6, Jan/2019), required download via github or backup.
Choose driver 2.5.0.4, install, restart.
So open the player.
Open Viper4Android FX app, try to apply some profile. Close and open the app if necessary.
Your Headphone need to be plugged.
NOTE: Don't forget to disable other features sound installed on your ROM like stock equalizer (AudioFX, Dolby and other).
To work correctly the Driver Status screen must be:
Driver Version: 2.5.0.4
NEON Enable: Yes
Enable: Yes
Status: Normal
Audio Format: Supported
Processing: Yes
Sampling Rate: 48000
NOTE2: The Viper4Android folder saves the profiles in the root of the internal memory and they need to be replaced in case of Internal Storage formatting.
I upload the files (older .apk and DDCs/Kernel) on my Mega
mega.nz
There is some perfis that I did for my headphones (JBL, Xiaomi, Bluedio, Phillips). You can try them and use it as based to fix all what you need.
Change it to others device you will need just set "Master Gate (limiter)" to 0dB on Alioth.
All them was set for Gemini (this need to be Output Gain -8.0 db).
NOTE3: I prefer the older version and older design. Just the older design app works with the folder "Profile" on .zip. The new layout migrates the folder "Profile" to "Preset" on new material design. This is not compatible.
As I said, you don't need to alter SELinux permissions.
There is a method that you don't modify that.