The open-source Android ecosystem beholds a slew of tweaks up its sleeves, one among which is the ability to improve the headphone/call sound quality by editing the mixer_paths.xml. But why is this required in the first place? Well, the OEM intentionally trims down the sound quality of its various components, including the in-call sound as well as the earphones.
While this might be done to preserve the quality and experience of the audio in the long run, however, this justification doesn’t seem to fit well in the dictionary of many users. And that is completely understandable. According to them, they should have complete control over their device and should be able to tweak them at their convenience. If you also echo the same thought process, especially with regard to the audio domain, then this guide is here to help you out.
Table of Contents
How to edit mixer_paths.xml to improve headphone/call sound quality
- To begin with, root your device via Magisk.
- Then mount the system partition read/write.
- After that, install a root-supported file explorer.
- Then go to the system > vendor > etc directory.
- You might get a magisk request, tap on Grant.
- You should now see the mixer_paths.xml file.
- Open it and then tweak it at your convenience.
- Once done, hit the save icon to save the changes.
That’s it. These were the steps to improve the headphone/call sound quality by editing the mixer_paths.xml file. If you have any queries concerning the aforementioned steps, do let us know in the comments. We will get back to you with a solution at the earliest. Let’s now get into the technicalities of The entire credits for the below explanation go to XDA Senior Member Elements 1984.
HPH vs RX: Simple Explanation
If you increase the RX volumes, you will get a digital boost. What that means is basically you WILL get a volume boost, but that boost comes with the cost of quality, and will clearly deteriorate the sound, making the sound feel very uncontrolled and distorted.
That is not normal at these volume levels with the headsets that I use, due to the fact that when I connect them to an iMac (which has a much more powerful and higher volume than what can be achieved on a smartphone/mp3 player due to its high-quality sound card) the sound keeps all of its details intact, with NO distortion.
The HPH (L/R) is what you’re after. This increases the analog volume (aka true volume), which raises all of the frequencies equally, giving you a real volume boost, without distorting the sound (if you have a low-end headset, at high volumes the sound could sound distorted not due to the phone, but because of the headset drivers/quality).
HPH (Amplifier/Electric Output) vs RX (Digital/Signal): Technical Explanation
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 and HPHL to as high as your device allows.
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 a constant electric current which could overheat the wires/transistors beyond what they were designed to take. Add to this a higher risk of internal ear damage.
Recommendations
My advice is to start increasing the HPH value to the highest possible value 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, save, restart, and try again. Basically, for me, with the aforementioned headset, the best settings are HPH-20 (both), and RX-85 (both).
You can feel free to play around with these settings, but the bottom line is, for most headsets, especially the in-ear ones that come bundled and other low or mid-range headsets, the best setting is increasing the HPH volumes up to 20 (or less if at max volume the headsets give out uncontrolled and distorted sound), and completely leaving the RX alone, as increasing it to levels above 85 basically destroys the sound quality, and we don’t want that.
For reasons I can not explain, raising the value above 20 (I actually tried it with 23 and 25, but I have the feeling even at 21 the same thing happens, though you are free to try and report on your findings) makes the volume drop way below standard. So what you want to do is increase both HPH levels to 20!
Facts: The loudness doubles at every +3 db, which means RX 85 should be 2 times louder than RX 82
