As with the standard AE2 headphones, you get a detachable headphone cable, so if you want to go wired, say, when the rechargeable battery on the module dies, you can. A USB charging cable is also included.
I reviewed the AE2 headphones a while back and it's worth noting that I like them. They offer good though not fantastic sound for their price range. But they're one of those pairs that you might use over even better-sounding headphones because of their comfort level. And for those who don't like active noise-canceling headphones, they offer decent passive noise isolation for half the price of the $300 QuietComfort 15 model.
The AE2ws have two modes: wired and wireless. In wired mode you remove the module and you're listening to standard AE2s -- and they sound the same as that model.
It's nice that you can go wired like that but I presume people are buying these headphones for their wireless capabilities and will rarely, if ever, use them in wired mode (perhaps only while the module is charged because it won't pass audio while charging). The AE2ws pair easily and, just as importantly, should pair again automatically when you turn the headphones on and have Bluetooth activated on your mobile device.
As I said in the intro, a lot of Bluetooth headphones end up sounding dull and muddy (thought they have been improving as the technology matures), so what I'm looking for in good Bluetooth headphones is that they don't sound like what they are. You want a pair that sounds natural and full, with good clarity -- and the AE2w is just that sort of Bluetooth headphone.
Part of the reason for that is a feature Bose calls Bose Active EQ. The company says, "The headphones also feature active equalization in the control module that provides a noticeable improvement to the sound quality. Your music and movies will take on a dramatic new dimension."
Yes, there's some digital processing going on, but all the good Bluetooth models seem to have some sort of extra digital secret sauce to help optimize the sound. The $399 Parrot Zik headphones are still among the best Bluetooth models (they add active noise cancellation and are a slight notch up from the AE2ws). We also like the $349
I'd say the Bose AE2w headphones are right there with the Harman Kardon BTs in sound. They're strong in the mids, and have pretty clean treble and punchy though not overpowering bass. It's fairly dynamic, though Bose leans toward a smoother, creamier sound that's warmer and a little less aggressive, which makes it easier to listen to the AE2w for long periods. The Harman Kardon BTs were a better fit for hard rock like AC/DC, but the Bose's balanced sound worked better with pop tracks. I tend to prefer better-balanced headphones that don't push the bass too hard, but if you like a bit more thump or a more aggressive sound, the AE2w headphones might not be for you. You do get a little more bass when you shift to wired mode.
It's also worth mentioning that when testing the headphones with our set of lossless (uncompressed) test tracks, I thought they played too softly. Switching between the AE2ws and the Harman Kardon BTs on a MacBook Pro, the Harman model was undeniably louder. (I tested the headphones with an iPhone 4S, iPhone 5, iPad Mini, Samsung Galaxy S4, MacBook Air, and MacBook Pro). The issue was less noticeable with standard MP3 files, but some users have complained that the headphones don't get loud enough and that Bose has limited the maximum volume.
Since the module has a USB connection, Bose could issue a firmware update, but part of the problem of optimizing Bluetooth headphones is that there are literally thousands of different Bluetooth devices out there, including computers, so it's hard to optimize for all devices. (You can connect two devices to these headphones at once and switch between the two sources.)
As for battery life, the headphones are rated at 7 hours but I managed to get a bit more than that, which means you should be able to get through most of day without recharging (the headphones do take a few hours to recharge).
Like most Bluetooth headphones, these have a range of about 30 feet, and they will cut out from time to time due to interference (Bluetooth signals actually don't pass through the human body as well as you'd think), so don't expect totally seamless playback. But it was mostly smooth sailing in my tests, walking around the streets of New York, riding the subway, and listening at my desk. And, as noted, I thought the AE2ws performed well as a headset for cel phone calls.
I think one of the reasons Bose has been relatively low-key about the AE2w Bluetooth headphones' arrival is that the company may not be entirely sure how they will go over in the marketplace. Some people will undoubtedly think the removable control module isn't a terribly elegant solution and wish Bose had built the circuitry into the headphone like it does with its noise-cancelling headphones. Also, if you do the math, Bose is charging $100 extra to turn the AE2s into wireless headphones -- only there's no option for current AE2 owners to buy the control module for $100, which would be nice.
However, despite a few question marks and the high price, I liked these headphones a lot. To be clear, I'm reviewing these as wireless headphones, and I've only come across a few Bluetooth models that combine good sound with a very comfortable fit. And while the Bose AE2ws may not surpass competing models in terms of sound quality, they're definitely a notch up on the comfort scale. The fact is I have a few reference Bluetooth models in my office (Harman Kardon BT, Parrot Zik) that I listen to regularly, but I found myself reaching for the Bose AE2w headphones for longer listening sessions. There's something to be said for that.