Cardo has churned out a number of great Bluetooth headsets in the past year, such as the Cardo Scala 700, which has a built-in headset locator, and the Cardo Scala Rider, a headset made specifically for a motorcycle helmet. This year, Cardo has once again pushed headset innovation with the Cardo S640, a Bluetooth headset with clip-on convenience. Instead of wearing the headset on your ear, you clip the device onto your shirt while an attached earbud can be placed in the ear or tucked neatly in the device itself. We feel this is a great solution for those that like having a Bluetooth headset but don't like wearing it all the time. The sound quality was great too. The Cardo S640 is available for $59.99.
The Cardo S640 is a small and compact device, only measuring 1.5 inches long, 0.7 inch wide, and 0.8 inch deep and decked out in a simple, glossy black. As we mentioned, the Cardo S640 is more of a Bluetooth clip than a headset--the entire device is the clip itself, with a wired earbud attached to the top. There's a volume button and an LED on the front of the S640, while the multifunction control button is located on the earbud. While we found the buttons pretty easy to press, we weren't too pleased with the concept of the volume button--instead of having a volume rocker that you can use to increase or decrease the volume, you have to cycle through the volume settings from lowest to highest with every tap. The wired earbud is a pretty standard size and fits comfortably in the ear. The S640 even comes with two earbud foam covers for additional comfort.
We tested the Cardo S640 with the T-Mobile Sidekick 3 and the LG Muziq. It paired with both handsets successfully, and we were very impressed with the call quality. Maybe it's because we could position the clip (with the built-in mic) closer to our mouths, but callers heard us loud and clear without any problems. On our end, voices sounded sharp as well, with little noise or static. Features of the Cardo S640 are pretty standard and include answering, ending, and receiving calls, voice dial support, call mute, last-number redial, and transferring a call to or from the headset. Also, the Cardo S640 has a built-in ringer that rings whenever there's an incoming call. The ringer can be disabled if you wish.
The Cardo S640 has a rated talk time of 6 hours and a rated standby time of 6 days.