To get more out of the headphones, it helps to download the FIIL+ app for iOS or Android. Oddly enough, the app asks you to log in with a social media account. As I had no desire to let FIIL access my Facebook or Twitter account just to use a pair of headphones, I logged in as "guest." The app will automatically detect the headset and display important info like battery life right on the first screen, including playback and standby hours. The battery on the Diva is great: When fully charged, the app was indicating 30-plus hours of music playback, and even after using the headset for three full workdays I still had 30 percent left in the battery.

The app is the only way to access the 3D sound feature, which simulates the experience of listening to music in different-sized rooms. The biggest of these is "Hall," which I guess is sort of like being at a concert. But I don't go to live performances because I crave a distant, echoey sound to my favorite songs, so this feature really didn't appeal to me.

Standard music playback is bright and crisp, and I found myself noticing details I often miss when using my earbuds. I listened to the entirety of Arcade Fire's Funeral, and I was surprised how clearly I could hear the chimes I had never even noticed before against the more aggressive guitars and drums.

I also experimented with My AudioFiilter at the office and on the street and found no measurable difference in audio quality. The voice prompt when you push the button should let you know which mode you're currently in, but the voice was too low, meaning that if I had music on I couldn't make out what was being said. Also, one of the recordings on my demo unit was still in Chinese. I figure this will be fixed in the final version, but it made figuring out which mode was active even harder.

There's also an opposite "Windy" mode that filters out wind noise; I tried this in a room with multiple fans and an A/C and it screened out the sound quite well. But it won't help with the constant pounding of your steps when you're walking or running, which seemed more pronounced on the Diva than other headphones.

I eventually ignored these odd modes completely and stuck with the standard settings.

Outside of these audio tricks, the Diva is designed for convenience. That means the good battery life and the touch controls, but it especially applies to the voice control and motion-sensing capabilities. The motion sensing is perhaps the marquee feature of the Diva headset. When you take the headphones off, the music pauses, and when you put them back on, the music should resume. It's a great idea: How many times have you taken headphones off and left the audio running because it took too long to fiddle with an app or find a tiny button? (The multifunction button on the Diva is pretty small.)

In practice, the motion sensing is finicky. I would take the Diva off and put it down, only to find music still playing when I returned a few minutes later. It takes a little practice to get it right: The instructions say to pull the headphones apart when you take them off, but I also found it helped to snap my wrist a bit when I took them off, and to take them off quickly. If I took them off slowly and carefully, the Diva never really seemed to get the message; if I was a little rough, the motion sensing was more likely to respond.

After some practice it became more reliable, but I can't say the same for putting the headphones back on. I tried pulling them, snapping them, praying; it didn't behave consistently, and I often just used the multifunction button to turn them back on. I also had some issues with the music cutting out for no discernible reason, or skipping tracks. The problems were more likely to occur when I was walking around, which makes me think it might be an issue with the motion sensing in my demo unit.

Another thing that needs to work: the voice controls. In theory, I should have been able to say, "Hey, FIIL, play Arcade Fire," and it would play a track. I never got it to work. There was at least one instance where I was holding the Diva in my hand and I heard a voice say, "I'm sorry, I didn't quite catch that." I was talking to my roommate at the time, and at no point did I say "FIIL" or even "hey," so I don't know what the headset thought it heard.

EDIT: Only the Diva Pro supports voice search; the regular Diva headset that I tested does not. I still have no idea what my phone (a Nexus 5X) thought it heard.

The FIIL Diva promises a certain level of freedom: not just from wires, but from fiddly controls and constant charging. And the potential is certainly there. Like its namesake, the Diva was lovely to look at and performed beautifully. But also like some divas I've known, it could be incredibly temperamental and unreliable.

If you want to try out some luxurious headphones and don't mind a few growing pains, the FIIL Diva is on Kickstarter today for an early-bird price of $129, with a future retail price of $199.