I recently bought these smartphones for around 80 USD each, just to be used as a Digital Audio Player. I also have FIIO X5, FIIO M6, Shaling M0, Aune M1s, Sony Walkman NW-A25, Cowon X2, etc.
Among them, only FIIO M6 has the wifi capability in it and is based on Android OS, but its user interface is not that comfortable to use as it is small and not as responsive as the smartphones. I had heard a lot about these LG Quad Dac and HTC 10, so thought of giving it a try, and luckily I got them at a very decent price and condition.
Starting with LG V20,
It has 32-bit ES9218 Quad DAC.
It only works through the 3.5 mm headphone jack.
Based on the device connected it automatically adjusts the power output.
On the other hand, HTC 10, with its 24-bit DAC and headset amplifier, has options like HTC BoomSound with Dolby Audio and Personal audio profile.
HTC BoomSound with Dolby Audio à
I prefer Other options as it sounds more natural and increases warmth, other options might sound better with those specified HTC headphones, but I do not have them.
Personal Audio Profile allows enhancing the sound output either by Answering quick questions like age, listening hours, genre and the other being listening to frequencies through the left ear and then right ear and doing the adjustments.
At the last step, we can test how the original and enhanced sounds and can save the profile with the name of our choice. We can create as many profiles as we want.
I normally prefer to keep both Dobly headphone effect (other) and Personal Audio Profile on.
Now coming to sound comparison between the 2 devices, they both sound very good just like any good DAP out in the market.
HTC 10 with its ‘Personal audio profile’ and ‘Dolby headphone effect’ gives us options of tweaking the sound which is not there in LG V20 (which anyways I will not prefer).
HTC 10 seems to have more powerful amp compared to LG V20, as it can drive my headphones slightly better than LG V20 if we compare the volume levels.
To conclude, LG V20 has a pure and analytical sound to it, whereas HTC 10 is more musical (although it provides sounds enhancements with Dolby and personal audio profile the sound still do not sound colored)
Let me know friends if you are looking for anything very specific in the comments and I will try to answer it for you (some of the headphones that I own and use for listening with these smartphones are Hifiman 4xx, AKG 7xx, Grado SR80e, Denon M400, Master and Dynamic MH40, Sennheiser HD 598 SR, Audio Technica ATH-AD700, V Moda Crossfade wireless, Beyerdynamics DT 770, DT 990, ATH 40x, 50x, etc.)