Unlike the Nexus 6P, the LG-made Nexus 5X only comes with a single front-facing mono speaker. While this is still better than the majority of other phones that feature either a rear or a downward facing speaker, it is still no match for the 6P’s front-facing stereo speakers.
Now, a mod from an XDA member sshafranko increases the volume of the earpiece of the Nexus 5X to make it act like a secondary speaker. sshafranko makes it clear that the mod will not make the 5X to sound like the Nexus 6P, but the improvement in quality is still noticeable. There is also a secondary mod that gives a fake surround sound effect, which while not real, does seem to make things sound better as per initial reports from other XDA members.
Since the earpiece was never made to act as a speaker, this mod can lead to some long term implications like the earpiece blowing out after a certain period of time. However, a similar mod was available for the Nexus 5 and a few other Android devices and in the long run, no one complained about the earpiece developing any issue.
Like with every other similar mod, installing this mod requires your Nexus 5X to be rooted with a custom recovery like TWRP installed.
[Via XDA]