Many audiophiles today eschew bluetooth completely. I have never been one of them. There are situations where using a dangly cord can be inconvenient or outright dangerous, and bluetooth was a "good enough for some" solution. Can the Astell & Kern XB10 ("Xtreme" Bluetooth) wireless DAC and headphone amp change this paradigm in any significant way?
About me: 37 years old, and I'll admit to being an audiophile. It comes from a formative experience hearing great DJ music on an exceptionally clean, well balanced 20,000 watt (or thereabouts, claim their ads) soundsystem at those notorious dance parties some of you have heard about. Hearing music so loud it became a physical thing, and realizing that all that mass of sound originated from a single point almost, the tip of the needle on the vinyl turntable was a profound experience.
Remarkably, my hearing hasn't deteriorated nearly as much as I later learned I should expect. I still hear 25hz and possibly below to 17.5khz and possibly higher. Cross your fingers that it continues to last that way!
Build Quality & Functionality: The most surprising thing about the XB10 is its size and weight. It's a wee little thing, about twice the diameter of a US quarter, and is commensurately lightweight. The outside is entirely plastic, but it feels tough enough to handle the relatively low force it would be exposed to if dropped. In practice, every time I've dropped it, it was caught by the headphone cable, and never actually made it as far as the ground. On the back is a removable belt clip, and I attached a strip of velcro underneath. I've found that I don't actually have to remove the clip for the velcro to get a grip with its mate.
The entire top of the unit is a 4-way rocker switch, symmetrical along one axis only. This does not make it significantly easier to operate without looking. The larger half controls volume +/-, one part of the smaller half is pause/play, the other half seemingly nothing. It has a bluetooth symbol and I may have pressed it once to pair it the first time. Track up/down buttons are along the rim, opposite the on/off/hold slider, which is confusingly identical in size and shape. To turn it on or off, you slide the switch one way and hold it there for several seconds, a tricky task, considering that hitting any of the other buttons on accident means you have to start over and try again. It takes a deliberate, conscious effort to hold it in the one awkward way where this is possible.
A rare positive feature of the design is the,decision to add a microphone on the unit, located by the headphone jacks. I don't often like using a microphone on a headset wire for phone calls, but I've found using the XB10 for calls to be convenient and easy, and the mic is apparently high quality (I'm told by everyone who's talked to me).
As a whole though, the controls are inconvenient, awkward to use, yet easy to hit almost any button inadvertently when the unit is in a pocket. Oh, and it can't reliably be operated in a pocket, you have to look at the thing, or else go: "okay, volume up is the direction away from the headphone plug, but was that on the right or left..."
This is the area in which I expect to see the most improvement when the inevitable XB20 comes out. I subtracted one and a half stars for these usability issues; it gained a half star back for everything else.
[A quick word on "wirelessness": while it successfully untethers you from your cellphone, the XB10 still needs a wire going from it to your ears. This can be essentially eliminated with clever use of velcro and a very short interconnect, but that trick is only possible with certain headphones. IEM users have it a little more difficult. I suppose you could velcro it to a hat or something, but I'd sooner just go with headphones. For most uses though, just throwing it in a pocket (with hold engaged!) was sufficient.]
Sound Quality (with apt-X): This is why I put up with the aforementioned inconveniences. The sound quality is, in a word, excellent. I detected no significant roll off at either of the spectrum's extremes, and no hiss with sensitive IEMs like the Ostry KC06a. My current phone is an LG G3, a one-time flagship with laudable sound quality, yet even listening casually at home, I'll often listen through the XB10 because I like it better than my phone's headphone jack. The DAC section is obviously well-implimented, and the amp is impressively powerful. The single ended 3.5mm TRS jack can drive just about any IEM and most easier to drive full size headphones, like the ATH-M50 or PSB M4U 1. Still, most full size cans gain a welcome bit of extra punch and sparkle using the 2.5mm TRRS balanced output. The balanced out is powerful enough to drive even power hungry full size cans like the 250ohm Beyerdynamic DT880 with real authority, quite impressive for such a small unit!
One drawback is a relatively short battery life (a bigger battery would add significant size & weight and would make for a very different product). However, I get around this limitation with an old, cheap external battery (with a built-in microUSB cable) I haven't used since like 3 cellphones ago. It wouldn't get me 33% on my current phone's battery, but it keeps the XB10 going for 10+hours. Another drawback is the cumbersomely wired TRRS. The correct wiring scheme is (from tip to sleeve): L+, R+, L-, R-. This is because a headphone hardwired in this way needs only a simple adapter (shorting pins 3&4) to be compatable with ANY common SE connection. Often a simple extension cable will do it. The strange R-, R+, L+, L- format used here has no advantages over any other random configuration that I can think of. It's A&K being different just to be different, and like so many of the design elements, it comes at the expense of functionality. It's only usable at all for the headphones I've rewired to accept removable dual mono cables, because I built a TRRS cable in the required format. I certainly wouldn't wire any headphones I like this way, leaving them useless for everything else.
Sound Quality (without apt-X): nothing to write home about.
Sound Quality (with apt-X HD): As yet untested, but extremely promising! Transmitting up to 24-bit/48 kHz, Qualcomm claims it's "indistinguishable from high resolution audio." I'm excited that a product that sounds great already might be able to sound even better! Currently the only apt-x HD capable sources are the LG G5 and LG V20, though it should become more common in the coming years.
Summary: Has the old Bluetooth paradigm been changed? Absolutely, yes. Although it has usability problems out the wazoo, the XB10's DAC and amp make it a must-use product anyway. It doesn't solve every problem.,and it will be more useful for some than for others, but if it's strengths line up with your needs, it's a fantastic product that I'm not even fully utilizing yet. If you can wait a year or two for the XB20, that's sure to fix a a lot of annoyances (right, A&K?), but the XB10 is still loads of fun to listen to already. I didn't get a free review copy, this review is based on a unit I purchased shortly after it was released.
Coming soon: pictures
About me: 37 years old, and I'll admit to being an audiophile. It comes from a formative experience hearing great DJ music on an exceptionally clean, well balanced 20,000 watt (or thereabouts, claim their ads) soundsystem at those notorious dance parties some of you have heard about. Hearing music so loud it became a physical thing, and realizing that all that mass of sound originated from a single point almost, the tip of the needle on the vinyl turntable was a profound experience.
Remarkably, my hearing hasn't deteriorated nearly as much as I later learned I should expect. I still hear 25hz and possibly below to 17.5khz and possibly higher. Cross your fingers that it continues to last that way!
Build Quality & Functionality: The most surprising thing about the XB10 is its size and weight. It's a wee little thing, about twice the diameter of a US quarter, and is commensurately lightweight. The outside is entirely plastic, but it feels tough enough to handle the relatively low force it would be exposed to if dropped. In practice, every time I've dropped it, it was caught by the headphone cable, and never actually made it as far as the ground. On the back is a removable belt clip, and I attached a strip of velcro underneath. I've found that I don't actually have to remove the clip for the velcro to get a grip with its mate.
The entire top of the unit is a 4-way rocker switch, symmetrical along one axis only. This does not make it significantly easier to operate without looking. The larger half controls volume +/-, one part of the smaller half is pause/play, the other half seemingly nothing. It has a bluetooth symbol and I may have pressed it once to pair it the first time. Track up/down buttons are along the rim, opposite the on/off/hold slider, which is confusingly identical in size and shape. To turn it on or off, you slide the switch one way and hold it there for several seconds, a tricky task, considering that hitting any of the other buttons on accident means you have to start over and try again. It takes a deliberate, conscious effort to hold it in the one awkward way where this is possible.
A rare positive feature of the design is the,decision to add a microphone on the unit, located by the headphone jacks. I don't often like using a microphone on a headset wire for phone calls, but I've found using the XB10 for calls to be convenient and easy, and the mic is apparently high quality (I'm told by everyone who's talked to me).
As a whole though, the controls are inconvenient, awkward to use, yet easy to hit almost any button inadvertently when the unit is in a pocket. Oh, and it can't reliably be operated in a pocket, you have to look at the thing, or else go: "okay, volume up is the direction away from the headphone plug, but was that on the right or left..."
This is the area in which I expect to see the most improvement when the inevitable XB20 comes out. I subtracted one and a half stars for these usability issues; it gained a half star back for everything else.
[A quick word on "wirelessness": while it successfully untethers you from your cellphone, the XB10 still needs a wire going from it to your ears. This can be essentially eliminated with clever use of velcro and a very short interconnect, but that trick is only possible with certain headphones. IEM users have it a little more difficult. I suppose you could velcro it to a hat or something, but I'd sooner just go with headphones. For most uses though, just throwing it in a pocket (with hold engaged!) was sufficient.]
Sound Quality (with apt-X): This is why I put up with the aforementioned inconveniences. The sound quality is, in a word, excellent. I detected no significant roll off at either of the spectrum's extremes, and no hiss with sensitive IEMs like the Ostry KC06a. My current phone is an LG G3, a one-time flagship with laudable sound quality, yet even listening casually at home, I'll often listen through the XB10 because I like it better than my phone's headphone jack. The DAC section is obviously well-implimented, and the amp is impressively powerful. The single ended 3.5mm TRS jack can drive just about any IEM and most easier to drive full size headphones, like the ATH-M50 or PSB M4U 1. Still, most full size cans gain a welcome bit of extra punch and sparkle using the 2.5mm TRRS balanced output. The balanced out is powerful enough to drive even power hungry full size cans like the 250ohm Beyerdynamic DT880 with real authority, quite impressive for such a small unit!
One drawback is a relatively short battery life (a bigger battery would add significant size & weight and would make for a very different product). However, I get around this limitation with an old, cheap external battery (with a built-in microUSB cable) I haven't used since like 3 cellphones ago. It wouldn't get me 33% on my current phone's battery, but it keeps the XB10 going for 10+hours. Another drawback is the cumbersomely wired TRRS. The correct wiring scheme is (from tip to sleeve): L+, R+, L-, R-. This is because a headphone hardwired in this way needs only a simple adapter (shorting pins 3&4) to be compatable with ANY common SE connection. Often a simple extension cable will do it. The strange R-, R+, L+, L- format used here has no advantages over any other random configuration that I can think of. It's A&K being different just to be different, and like so many of the design elements, it comes at the expense of functionality. It's only usable at all for the headphones I've rewired to accept removable dual mono cables, because I built a TRRS cable in the required format. I certainly wouldn't wire any headphones I like this way, leaving them useless for everything else.
Sound Quality (without apt-X): nothing to write home about.
Sound Quality (with apt-X HD): As yet untested, but extremely promising! Transmitting up to 24-bit/48 kHz, Qualcomm claims it's "indistinguishable from high resolution audio." I'm excited that a product that sounds great already might be able to sound even better! Currently the only apt-x HD capable sources are the LG G5 and LG V20, though it should become more common in the coming years.
Summary: Has the old Bluetooth paradigm been changed? Absolutely, yes. Although it has usability problems out the wazoo, the XB10's DAC and amp make it a must-use product anyway. It doesn't solve every problem.,and it will be more useful for some than for others, but if it's strengths line up with your needs, it's a fantastic product that I'm not even fully utilizing yet. If you can wait a year or two for the XB20, that's sure to fix a a lot of annoyances (right, A&K?), but the XB10 is still loads of fun to listen to already. I didn't get a free review copy, this review is based on a unit I purchased shortly after it was released.
Coming soon: pictures
I bought the BX10 a two weeks ago. I can fully agree: The sound is better than any Bluetooth I had listened before, it allows flexibility and great performance. Normally using a Sony Xperia Z 5 phone, I do not use the phone for audio, because I'm not really happy with the sound. But now... I changed my behavoir and use the xperia a couple of times a day. Since the XB10 is in the house, I use the RHA20 or Dito "The Answer" more often as Headset.. Simply Great.