Speakers are getting smaller and smaller these days, but can a speaker be both truly portable and worthwhile? A spate of reviews of one of the leading mini-speakers suggests we aren’t quite there yet.

The X-mini lauds itself as “Sound Beyond Size.” It’s a cool idea, on the face of it. The X-mini is a class of speakers form a Singaporean startup. The things are adorable–they look like some sort of lovechild between a robot and a yoyo–and you can even get one in Hello Kitty style, if that’s your thing. The X-mini’s genealogy actually dates back to 2008. You can see it in action in plenty of YouTube videos. Here’s one good walkthrough, for instance.

The young lady there calls it “one of the best portable mini-speakers on the market,” which may well be true, but to judge from more recent reviews, the fact of the matter is that mini-speakers like these, while very cool and incredibly portable, still leave something to be desired.

“To be blunt, it’s not remarkable,” Engadget says in its recent look at the X-mini KAI capsule. Even novel features meant to increase the sound come up short. “The accordion-like ‘resonator’ feature, while very, very cute, is almost worthless as far as providing more frequency response,” says Engadget’s Trent Wolbe. Others are slightly more generous. “While the KAI sounds amazing for such a small speaker, don’t expect thumping bass lines,” said CNET Asia.

To be sure, the KAI is a feat of engineering. It’s about 2.5 inches in diameter and a mere 2 inches tall; it’s basically the size of a baseball, small enough to toss in a bag almost as an afterthought. And its Bluetooth capability means pop-up music sessions are super easy to create. “We found a boatload of tiny cases where the KAI is useful enough to overcome its shortcomings in reproduction quality,” says Wolbe. Its Bluetooth connectivity makes it something like a Bluetooth headset, only off of your head; you can even set up a daisy chain of KAI’s to amplify sound or to mic a whole conference table. CNET tested calls, and found the KAI to be “clear and adequately loud,” though as soon as you got about a meter away from the thing, the person on the other side of the line had trouble hearing.

Reading about the X-mini KAI, one has the sense that a clever company has done its best, and has produced something worthwhile, but that many consumers are ultimately going to be left a little disappointed, if they’re expecting big sound. The KAI is cute, to be sure, and offers a few innovative uses–one of which might well be for you. But if you’re craving a solid bass line, and the ability to crank up your music on the beach and still get good quality, something the size of a baseball still just won’t cut it.