I've been looking for a mod to increase the headphones volume of my Z1C. I've found a lot, for various Xperias, Android versions, with various settings. Some where over-increasing the volume, to the point of distorting it. Having in mind that using a mod for another Xperia (even similar with Z1C) or another Android version, might have a negative impact to other aspects of the devices audio, I decided to make my own tweak!
So, after a lot of search and testing, I tweaked and modded my mixer_paths.xml from the last Z1C firmware (.236), to have the max possible headphones volume with no audio distortion at all. That is accomplished by raising the values of HPHs to the max (20), while the values of RXs were slightly raised only by 3 (to 85, which is the max value for no distortion I think). The result is awesome! No, other sound mods needed! Just the Sony sound enhancements, which I think are the best out there, having in mind Sony's experience on sound systems. Boom bass and crystal clear tremble! Just try and see!
More technical detail can be found here:
[Guide + Technical Explanation] Boost the headset volume without losing qualit by Elements1984
A big thanks to Elements1984
for this great guide!
To the point now. How to install:
1. Take a backup of the existing mixed_paths.xml file in system/etc folder!
2. Replace it with the attached one.
3. If necessary, set its permissions to 644.
5. Enjoy and don't forget to hit "Thanks"!!!
P.S.1 This will probably be suitable for Z1 too, since they are (almost?) hardware identical. May work with other Xperias or Android versions too, but try it at your own risk!
. After all, there's not much risk if you take a backup of your mixer_paths.xml.
P.S.2 Have in mind that volume and overall sound has to do a lot with the headphones quality.