When choosing a new smartphone, it's often hard to find something with literally every feature you want. You might have to go without things like wireless charging or the latest and greatest processor in order to get the best overall fit. However, one thing you haven't had to worry about losing is the headphone jack. That may well be a real concern in the not too distant future.

Motorola is has announced the Moto Z without a headphone jack, and although this isn't the first foray into Android phones without a standard 3.5mm jack, it's certainly the most high profile.

Headphone History

In some ways, this feels like a real blast from the past. The first few Android phones in 2008 and 2009 didn't have headphone jacks either. Back then, HTC was fond of the extUSB port, a tweaked version of a standard miniUSB with a few extra pins that could carry analog audio. This graced such iconic devices as the HTC Dream (T-Mobile G1) and HTC Magic (Google Ion/T-Mobile MyTouch 3G). A version of the latter was re-released later with a 3.5mm headphone jack because let's face it, not having a headphone jack is annoying.

A headphone jack is the standard way of outputting analog audio, but the early experiments in jackless phones were doing that as well. You could use an adapter for the extUSB port to get a standard 3.5mm jack, or use headphones with extUSB. I think about four of those ever existed because it was far too early to ditch the 3.5mm jack.

However you get audio out of your phone, it needs to be an analog signal when it reached your ears -- something has to process the digital signal, and thus far that has always happened in the phone with a DAC (digital to analog converter). Some phones have toyed with using more powerful, high-end DACs for a supposedly better audio experience. LG even sells a DAC module for the G5 in some markets.

A few OEMs think that the move to the reversible USB Type-C plug is the perfect time to get rid of the old standard, but it might not be a clean break with the past.

The Jackless Phones

Motorola's upcoming Moto Z family of devices is the most high-profile to drop the headphone jack in modern times, but it was beaten to the punch by a few Chinese OEMs. The first was Oppo when it launched the R5 in late 2014. This phone was just 4.85mm thick and used a microUSB port for audio output via a bundled adapter. Bluetooth was an option as well, of course. This phone was never released widely, and even in China it was a flash in the pan.

Moto Z

LeEco (formerly LeTV) is big in online video in China, and is an up and coming smartphone maker. It announced three new phones several months ago, the Le 2, Le 2 Pro, and Le Max 2. All of them have just a USB type-C port for both charging and audio. They're just for the Asian market right now, but LeEco has not ruled out bringing similar devices to other markets and has already opened offices in the US.

Motorola slimmed down the Moto Z dramatically this year, presumably as part of its project to make room for the modular Moto Mod back plates. The Z and Z Force are a mere 5.19mm and 6.99mm thick respectively (the Force has a much larger battery). On the bottom of these phones is just a USB Type-C port, but they will be bundled with a 3.5mm to USB-C headphone port adapter.

How's Will This Work?

The goal is to get the digital signal from your phone into your ears as analog sound waves. To do that, you need to convert the audio either in the phone our outside the phone. We already know how LeEco is doing things, and I think we can mostly agree it's the less desirable option. LeEco is pushing a standard of its own design called CDLA (Continual Digital Lossless Audio). CDLA requires special headphones because the Type-C port doesn't output analog audio.

Le Max 2

LeEco has created two headphone products that support CDLA, which contain the processing and decoding hardware needed to convert digital into analog. According to LeEco, doing that in the headset improves audio quality compared to passing analog over a 3.5mm jack. And you know, I'm sure you can come up with a very convincing engineering explanation that backs that up. Was anyone really concerned about the audio quality of the 3.5mm jack? Most people are using inexpensive headphones that would never allow them to perceive any tiny loss of quality from the analog output. Even with high-quality headphones, I doubt this makes any difference in the range of human hearing.

The problem with this approach is that CDLA will shift the processing into headphones and make them heavier and more expensive. From what I can gather of the spec, there's also no way to split the Type-C port to both charge your phone and get audio output at the same time with CDLA. One upshot, they'll be able to do active noise cancellation without a separate power source (they get juice from USB). In the end, the entire thing just seems unnecessarily complicated for headphones, and it will require every maker in the industry to adopt specific hardware specs.

The other way to do away with the headphone jack seems, frankly, less annoying. The USB Type-C spec allows for so-called "alternate modes" that could be used to output video or audio. In this case, we're talking about an audio signal described by the audio adapter accessory mode. In fact, the spec calls for the Type-C port to output the same four analog audio signals you'd get over a traditional 3.5mm jack. The phone's internal DAC still does all the heavy lifting, so you just need a passive Type-C to 3.5mm adapter or (eventually) headphones with a Type-C connector. This is what I suspect Motorola will do, though it has not explained in detail yet. It's just a much more consumer-friendly move -- well, friendly in the context of removing the 3.5mm jack at least.

Type-C accessory mode also allows for an adapter cable to be split. That means you could both charge your phone and get analog audio out of the Type-C port at the same time. So, you'll need to have the adapter on hand. In general, the move from 3.5mm to Type-C only is going to come with some pain. Even if Type-C alternate mode becomes the preferred method, you'll have to carry some adapters around for a bit. This may encourage some people to just pick up some Bluetooth headphones and avoid this whole mess.