[Samsung Galaxy Player 4.0, 5.0] Windows X:
I'm building a new ROM for my new Xperia Z right now mainly for even better audio quality. However, it'll take a while as I plan to try rebuilding audio driver library file for lower latency. Right now I'm on vacation staying at my parents' house so I decided to build this sound mod for Samsung WM8994 devices instead since I have good chance to reunite with all of them right now.

FidelityXAudio is based from PureXAudio for Xperia Z/ZL made by ZeroInfinity. I asked him for permission to derive his works with mine for all-in-one sound mod I plan to release for various devices that support Alsa driver. For this first release, it'll support Nexus S, Galaxy S, Galaxy Tab and Galaxy Tab 10.1 and all variants. Installing this mod will give you the following features below.

Features:

Rooted & Busyboxed - This will replace current root and Busybox with latest SuperSu and Busybox. Since most root access for Xperia Z I tested are so unreliable getting bootloop after mounting system rw, I'll force better ones in this package to avoid that problem.

exFAT support - If you're using Android JellyBean ROM but still not have exFAT support yet, this may help you getting one. It works for Xperia Z/ZL but haven't tested for others yet.

init.d support - This isn't cheap recovery flash init.d script. It'll execute init.d script with root access from hardware boot script level so it works far better than conventional ones for locked bootloader running stock kernel.

Xperia Fidelity script - It's ultimate sound quality mod script I've been developing for years. Not only get you better sound reproduction but also make your system smoother as well.

PureXAudio engine - As FidelityXAudio is based on PureXAudio mod, most PureXAudio features are availble except audio effects and specific sound card stuff. I may consider adding them back later though.

Low latency tweaks - My tweaks inside PureXAudio for lower latency Alsa configuration. Not sure how much of it works though as real measured hardware latency won't change without modifying driver.

Mastering 64-bit quantization - The most accurate 64-bit floating point quantization in Android. I usually end it with 32-bit integer mode but this sounds better for crazy upsampling level.

DSD128 audio processing at 5.6MHz - This will give you high resolution audio simulation. The real sampling rate will still be 44.1KHz but with 128x upsampling for audio processing before downmixing is really something.

Fidelity nVIDIA audio configuration - Optimized for more direct bitstream with lower latency. Only for Tegra devices though.

Removed DSPManager for more solid audio performance - This mod breaks DSPManager in CM ROM so no point in keeping it and you probably won't need it anyway after hearing sound with this mod.

Download: PureXAudio v1

You can't flash this on other devices as it can break audio with incompatible sound card configuration. I tested on my Nexus S, Galaxy S, Galaxy Tab and Galaxy Tab 10.1 and they're all working fine. Guess not many people still use them nowadays but they're great ones for sound quality wise. I'll update again for APQ8064 based devices in next version after releasing new Xperia Z ROM.