If the Sleek Audio SA6 earphones have a claim to fame, it's their modular approach to tuning the treble and bass response to your taste. While the Sleek Audio SA6 earphones work great right out of the box, three pairs of interchangeable Treble Tips and Bass Ports are included with the package, allowing you to increase or decrease the perceived amount of low end or high end for each ear. Be warned, you do have to be fairly nimble-fingered to swap out these tiny parts, but once you've configured your perfect recipe for audio bliss, you probably won't need to revisit the tiny parts again.
Another distinguishing feature found on the Sleek Audio SA6 earphones is their detachable cable design. The included headphone cable connects to the SA6 earpieces using a miniature, gold-plated coaxial jack found in the back or the earpiece. This detachable cable design not only makes it easy to replace broken cables, but the use of a rotatable coaxial connection makes it easier to position the cable around the ear. The downside to all these detachable parts, of course, is that there's approximately nine little parts to lose at any given moment.
We listened to a variety of music using the Sleek Audio SA6 earphones configured in multiple ways, and the overarching sonic character was a dip in the high-mid range. Vocals felt a little buried in the mix of songs such as Sia's live performance of "Blow it All Away" and such instruments as pianos, horns, and strings generally felt a little muted. On the low-end, the Sleek Audio SA6 earphones really shined. Low frequency instruments such as bass, keyboard and kick drum really punched through, especially in classic studio recordings such as Stevie Wonder's "Too High."
For a single balanced-armature driver housed in an extremely small and lightweight earpiece, we thought that the sound quality of the Sleek Audio SA6 earphones was impressive. For $250, however, we have a short list earphones in this price range that we prefer, including Shure's SE310, Ultimate Ears' Super.fi 5 Pro, and the ugly duckling Future Sonic Atrio M5. While we applaud Sleek Audio for creating an innovative design that gives users better control over customizing their experience, the final results were sonically mediocre when held up to the competition. Also, all the tiny, fragile, detachable components involved in the SA6 earphones didn't inspire the confidence we wanted in a road-worthy product.