Viper4Android FX is an audio mod for rooted devices that enchances audio using the following FX:

FX Settings Explained
< Headset >
1. Master Power. This option defines whether to enable V4A headset sound effects, also known as main switch.

2. Playback Gain Control. It is mainly used to dynamically control the audio volume, to amplify or to attenuate.

3. FIR Equalizer. 511-order 10 bands FIR linear equalizer.

4. Convolver
When an impulse response(IR) sample is loaded, music will show the same characteristics of the loaded sample, for example equalizer, surround, reverberation, tube etc.
Make sure SD Card has /ViPER4Android/Kernel/ folder, IR samples will be located there. If folder not exists, you can download latest V4A FX and extract SDCard_V4A.zip.

5. Field Surround. It is mainly used to create sound field surround effects. The sound field can be understood as mono field or stereo field.

6. Differential Surround also known as Haas effect.

7. Headphone Surround +. Virtual Headphone Surround effect.

7. Reverberation. It uses mathematical methods to simulate the environmental feeling sensation. Example a song can be felt playing inside the auditorium, living room, bathroom, and so on.

8. Dynamic System. It handles the dynamic range of the sound. In other words the bass, treble, and limiting.

9. Fidelity Control. It’s a substitution for XHiFi’s Audio Reconstruction. It handles bass and clarity of the sound.

10. Auditory System Protection. Protects auditory system.

11. Master Gate(Limiter). This option is V4A output limiter, its used to prevent overloud clipping distortion.

Viper4Android link: https://drive.google.com/file/d/1eE_JjRjSDus_WkAo0S_mD8zdOeJYSmYh/view?usp=drivesdk

My preset down link: https://drive.google.com/file/d/1pdm5XsJDB5iWnf4wDDLK_zomGCTxEk2Q/view?usp=drivesdk