[Xperia Z1 Themes and Apps] Elements1984:
Guide + Technical Explanation

Thank you Barkohba for this great explanation, this is the way people should be setting their sound.

I have been working as professional DJ and sound engineer for serious gigs since 15 years and I would like to clarify what was already wonderfully well explained by Barkohba, so here are the facts:

HPH (amplifier/electric output) vs RX (digital/signal):

HPH: Basically, the best way to get a volume boost without decreasing the sound quality is to increase the amount of electric power that your device outputs, this will have the effect of feeding your headphones with more power which will generate more acoustic pressure (DeciBels/db) without degrading the quality (provided you didn't reach the limits of your headset). To do this, just set your HPHR to 20 and HPHL to 20

Rx: This is somehow the input signal of your sound, increasing this value will boost the source signal which will create distortion and saturation, this will result in a sound that will feel louder because of the generated compression, but the cost is a loss in dynamics and quality, the loss is proportional to the increase in the signal. In other words, increasing the RX value will distort and saturate the sound, you will have a louder but poor sound quality with a huge loss of bass and a flat sound, with the possibility that

this will fry/damage your phone sound card and/or headphones at high volumes because of the saturation generating constant electric current which could overheat the wires/transistors beyond what they were designed to take

. Add to this a higher risk to internal ear damages.

My advice is to start increasing the HPH value to 20 first, save the file, reboot and see if the sound boost is high enough for you. If that was not loud enough, then try increasing the RX value by +3 (or to 85), save. restart and try again.

Facts: The

loudness doubles at every +3 db

, which means

RX 85 should be 2 times louder than RX 82

Conclusion: The first step to boosting your sound is to increase the HPHR to 20 and HPHL to 20. If more loudness is needed, increase the RX value gradually by +2 or +3 until you reach the desired loudness (RX 85 is a good balance, I wouldn't recommend going beyond RX 87). Keep in mind that too much increase in RX will make you lose bass and sound quality, at that point don't expect the equalizer (EQ) of your music player to give you more bass or improve your sound quality because you have saturated/damaged the sound at its origins.

I hope this will help you set your sound at the desired levels without damaging your sound quality or devices or headphones or ears.

Note: I am using these settings on my Xperia Z1 with my Sony MH1C headset, these values should work for the Xperia Z1 Compact because it has a similar hardware. Theorically, this guide is universal and can be adapted to work with any android device, the values in mixer_paths.xml might be different on other devices but the boosting principle is the same.

More infos:

HPHR = Right output and HPHL = Left output

People with impaired hearing can set up these 2 values differently. HPH? 20 should be for the weak ear, set the value for the strong ear at anything below 20 until you reach the balance between the 2 ears.