HTC has long been known for two things; the absolute best build quality and attention to sound. Past phones included HTC BoomSound in the form of two speakers on the face of the phone. It's a great idea and one that was universally praised, which makes the speaker placement on the new HTC seem odd. At first glance, it seems to just have a speaker near the USB type C charging port, but more is going on than meets the eye. There is a second speaker on the face of the phone, in the same place as the built-in earpiece. Too me, this seemed even stranger but there is a method to HTC's madness. The front facing speaker handles the high frequencies and the one next to the charging port handles the bass. Yes, it's an unusual configuration, but it really works.
I don't use my phone's speakers too much for movies or music anyhow, so I didn't figure it would be that big of a deal if the external audio was lackluster, but there is no need to worry; it's sounds great. It's loud, articulate, crisp and clear. I do use headphones, often earbuds, but when at home, large headphones -- headphones that often require the use of an external headphone amplifier to properly drive them. HTC has more than a few tricks up their sleeves when it comes to headphone audio. First of all, the HTC 10 has the most powerful built-in headphone amp that I'm aware of. They rate the amp's distortion at .001% at -104 dB when used with a 32 ohm load. The noise level is -120 dBV! I can't hear any noise at all with any of my headphones at any volume level. But that's only part of the story.
The HTC 10 features something they call Personal Audio Profiles, and it works like this: everybody's hearing is a little different. Some people can hear better than others, but even if there's nothing wrong with your hearing, you'll still be a little more sensitive to some frequencies than others. Also, every model of headphones play back sound a little differently, let's say, for lack of a better word, they all have certain inherent imperfections. Even good headphones have some frequency that's a little off. Personal Audio Profiles lets you fine tune all of your headphones to your specific hearing! The menu to access it is only visible when headphones are plugged in, so do that first, and then when you start the profiling, a very quiet, and very low pitched sound will play in your left ear. All you do is turn the volume up and down on the screen until you can just barely hear that frequency. Then it plays the another frequency that's a little bit higher in frequency than the first, and you adjust that until you can just barely hear it, and so it goes until you have finally adjusted it for the middle and high frequencies. Now it starts the same series of tests over again but for the right ear. Name the profile to that model of headphones and save it. You can have multiple profiles. I even have a profile for my good headphones when I measured them in a noisy environment, as that too will further affect how you perceive various frequencies.
What this does is make cheap headphones sound great, and great headphones sound even better. Bass goes lower, but remains really punchy, never muddy. Mids are articulate and highs are lush but never harsh or painful. I've never heard any of my headphones sound this good. Ever. It is nothing short of incredible.
But wait, there's more. No, it doesn't julienne fries, but the digital audio converter in this phone up-converts 16-bit digital audio to 24-bit before converting it to an analog signal. This too is done really well. Everything sounds smooth and natural. I'm hearing low end bass from cellos that I haven't heard before from my recordings, even with my "good" headphones. If you are into music, get this phone. There is nothing else on the market like it.