Cork: Micro Bluetooth Speaker Uses Empty Bottles to Boost Sound

Reading Time: 3 minutes
Cork speaker uses bottles
Cork speaker mounted on bottle, with Cork Cradle on the shortest bottle (Photo by Brad Moon)

I don’t often cover crowdfunding campaigns, but this one is kind of cool. Plus they have a shipping product (which I was able to review hands-on) and they’ve already met their funding goal—so not much in the way of risk. Cork is a micro Bluetooth speaker that sits on top of an empty bottle (like a cork), using the bottle itself to amplify and customize the sound that’s produced.

Cork is shaped somewhat like its namesake but on a larger scale. My review unit was white, with an LED indicator and power button on one side, and a microUSB port for charging on the other. A tiny grill circles the bottom third of the unit. You charge the Cork and pair it with your mobile device as with any other Bluetooth speaker, but that’s where the similarity ends.

Look at the bottom of the Cork and you’ll see an exposed, downward-facing driver. Crank up the music on your phone and, frankly, it will sound… a little terrible. Tinny, with very low volume. Set the Cork on a table and it’s worse. The volume goes up a bit, but now the sound is completely muffled.

However, also in the box are two silicon “cradles,” and this is where things start to get interesting. Each will fit snugly to the bottom of the Cork, but one is designed to fit securely around the outside of the neck of a bottle, while the other fits inside wider-mouth bottles.

Cork speaker is ultraportable
The Cork speaker itself is a tiny thing, weighing just 3.52oz (Photo by Brad Moon)

Pick an empty bottle, attach the Cork to the appropriate cradle and stick it on the neck. All of a sudden, music playback improves as the bottle becomes the missing enclosure for the Cork’s driver. Generally speaking, you’ll gain significantly in low end response and volume, but the characteristics of the sound produced vary considerably by moving Cork from bottle to bottle. My kids thought it was pretty cool and switched the speaker between different bottles to see how shape, material, and size affected the sound. You can even get funky with a bottle that has a hole drilled in it—spoiler, that produces just a hint of reverb and you can feel the air being moved by the driver at high volume.

Even at its best, the Cork can’t keep up with most Bluetooth speakers in its price range when it comes to overall sound depth. It is just a single driver with a 1.7W amp, after all, and most portable speakers are dual-driver units with considerably more power on tap. But with the right bottle, it can produce a surprising amount of volume with decent quality audio, and there’s no denying it has a definite cool factor. Not to mention its portability (assuming there’s an empty bottle available at your destination).

In terms of battery life, it’s rated at 12 hours and I was averaging 10+ hours with Cork frequently at high volume. Cork uses Bluetooth 4.1 exclusively for connectivity.

Leedeyeon is promoting the Cork as a way to recycle bottles, but I think it has just as much application as a learning opportunity for acoustics. If nothing else, you could get a new speaker “look” every day… It’s a little late to be making design changes at this point, but my wife took one look at it and said they should have included a little LED light on a wire to hang into the bottle and turn it into a combo speaker/mood light. Maybe for Cork 2?

Cork’s Kickstarter can be found here. The speaker will be priced at $63, but there are early bird packages currently available, including discounted Corks, multi-packs, and different color options. Orders are expected to arrive in December.

Disclosure: A Cork speaker was provided for review purposes.

Get the Official GeekDad Books!