We just finished having a look at how well the new Google Now music ID service works, and here we are with some not-so-good news. It's broken on HTC Sense. At first, you'd get an ugly error, and a force close when you tried to use it. But Google has changed something on the server side and you're presented with a slightly more friendly note that "this action is not support on this device." Neither is good, but the latter is better, I guess.
The reason why it doesn't work is simple -- the original Jelly Bean Google Ear app isn't included in Sense 4+. The new Google Now method is simply calling it with a different interface, and since it's not there it is no bueno. We're not the only ones who noticed this either -- Russell over at Geek.com came to the same conclusion we did -- if you can sideload the app you can get it to work.
That's fine for you and me (and Russell). We can deal with little nags like this, but in the bigger picture HTC and/or Google are hopefully going to address this. We've reached out to HTC to see what they say, but since we saw the server-side change we wanted to address it tonight.
The "real" fix is for Google to drop the music ID service into the Play Store, and change the message for HTC devices that it is a required download. Or for HTC to just send out an OTA to take care of it, but that one is a stretch. In the meantime, be sure to hit the forums if you feel like fixing your DNA or One X phone by hand.