There's just a single, large dial on the front of the ONE, which is used to operate all aspects of the device, though all operations can be carried out via Apogee's Maestro app for Mac and iOS, too. Above the dial is an LED input / output level meter and above that an LED input / output indicator (internal mic, external mic, instrument and volume). When using the ONE's built-in mic, it was particularly useful to have the level meter on the front of the device to reference input levels, instead of looking to my Mac or iOS device to see if things were peaking or too low.
On the top of the device is a microphone / instrument input (expandable via breakout cable), a micro USB input (to connect to a Mac or iOS device) and a DC power input. All cables and the power supply are included with the ONE. The bottom side of the device has a 1/8" stereo output for headphones or powered speakers.
The ONE's breakout cable gives you a 1/4″ instrument IN and an XLR IN. The devices allows you to have 2 simultaneous inputs: the instrument IN and the XLR mic IN or the built-in mic with the instrument IN. Of course, you can just use the ONE's built-in mic without the breakout cable attached.
On the rear of the device is a battery compartment for two AA batteries, though these were not included. Powering the ONE with batteries eliminates the power supply from the mix when using the ONE with an iOS device, which dramatically adds to its practicality in a portable context.
One glaring omission is MIDI input, especially for a device that's iOS compatible. With so many apps designed for MIDI use on iOS, it feels like the ONE's missing a trick.
Performance on iOS
Connecting the ONE to my iPad was just as easy as connecting it to my Mac. However, the first hurdle was power. iPads and iPhones won't power the ONE like a Mac does, so I opted to use the included power supply (though I could have gone for the battery option had I any to hand). On the plus side, using the power supply with the ONE meant that my iPad was charging instead of draining away.
The next step was downloading Apogee's Maestro app, which is required for Mac as well. The app allows you to control all features of the ONE as well as improving latency issues. Once Maestro was installed, I launched GarageBand and got to adjusting settings.
It took me a little while to get a good level because I was unfamiliar with the Maestro app. I found myself repeatedly switching between GarageBand and Maestro, trying to get a level that didn't peak, but wasn't too quiet. I found this process cumbersome, but once I was a bit more familiar with Maestro, things seemed to improve. That being said, The Maestro app does feel like a bit of a third wheel. The interface is akin to its desktop counterpart. Although that may be a comfort to those who've used it on the Mac, it doesn't feel at home on iOS. Buttons and sliders are small, for example, particularly on the iPhone. It's still workable, but a Maestro app designed solely with iOS users in mind would go a long way to improving the experience.
Performance on OS X
Really, there's not much to say here. If you've used an Apogee interface with a Mac, you know it's a solid combination. The ONE felt right at home with my Mac. I can't put my finger on it -- maybe it was simply familiarity -- but everything worked as you'd expect it to. The Maestro app is still required, but it does fit much better in place on OS X than iOS.
Once I got to some recording, I was really surprised with the results. Using a Rode NT 2000, I found I was getting some fantastic results for the first time on my iPad. Similarly, things sounded great on OS X running Logic. But for me, the big surprise was actually the ONE's built-in microphone. It admirably handled whatever I threw at it. Once I realized how compelling the built-in mic was, the ONE began to make sense to me.
You see, there are many external mics for iOS out there, but the ONE's mic in combination with Apogee-designed preamps and digital audio converters makes it a compelling package for recording audio on iOS (or Mac). You really can just plug in and record. There's no need for additional cables or mics. And you do get a fantastic sound out of it.
Plugging the ONE straight into my Mac and putting something down at a moments notice is a real plus, especially when the quality of the audio sounds this good. More so, for those moments where it's easier to grab your iPhone or iPad, the ONE produces the same results.
The revamped ONE carries Apogee's name well. For its class, it's got stand-out preamps and converters and a built-in mic that really impresses, with expandability if you need it. And all of this in a highly compact and portable form factor. If you're looking for that kind of convenience, but without skimping on quality, the ONE is a solid choice.