Pros: A pair of substantially user-customizable earphones, complete with three sets of bass ports, four sets of treble tips, three double flange ear molds, and detachable cables that can be used to change how the earphones fit, rest on your ears, and sound. Independent bass and treble adjustments enable you to tweak audio levels to achieve a balance suited to your personal needs. Includes nice plastic carrying case and cleaning tool.
Cons: Tweaks to treble and bass are generally small, rather than pronounced, and audio drivers don’t rival the best-sounding $200 earphones we’ve tested. Small pieces can easily be lost.

Ninety-nine percent of earphones are designed to sound a specific way when placed in your ears: some are really bass-heavy, others are “flat” and neutral, and still others are tweaked to exaggerate both bass and treble. The pair that sounds really good with certain genres of music might not sound as impressive with others, and because of differences in some ears, a pair that fits one person might not fit another.
Ninety-nine percent of earphones are designed to sound a specific way when placed in your ears: some are really bass-heavy, others are “flat” and neutral, and still others are tweaked to exaggerate both bass and treble. The pair that sounds really good with certain genres of music might not sound as impressive with others, and because of differences in some ears, a pair that fits one person might not fit another.
Sleek Audio’s SA6 ($250) is designed to address both of these concerns in a single product.
Like virtually every other in-canal earphone on the market, SA6 comes with three sets of silicone rubber tips that are designed to provide a good seal in any sized ear. These happen to be double flanges—basically, a small tip on top of a larger tip—so that the larger tip can block out ambient noise that the smaller tip might miss. Sleek Audio also includes a cleaning tool and a relatively deluxe hard plastic carrying case, parts typically found in earphones sold for $100 and up.
Those aren’t the parts that are supposed to justify either SA6’s price or its general existence. Unlike any other earphone we’ve reviewed, SA6 is packaged and marketed as a do-it-yourselfer’s high-end canalphone, including three total interchangeable bass ports, four different treble tips, and detachable 360-degree cables. The cables can be twisted to wrap around the tops of your ears, or dangle from their bottoms; Sleek also claims that you’ll be able to detach them entirely for use with an as-yet-unreleased wireless accessory. That idea: pull off the earbuds, mount them on a mini-cable attached to a wireless receiver, and enjoy your music without requiring further cable length to connect to the iPod.
You might also attach the earbuds to an iPhone-friendly cable, as the one included here is for iPods only.
That all raises an obvious question: why would anyone care to use the SA6 earbuds with different cables, or a wireless accessory? The answer is in what happens to the earbuds when you start tinkering with them. Sleek Audio ships SA6 with comparatively neutral parts pre-installed: out of the box, you get the “normal” treble tips and “normal” bass ports. But if you pull these parts off, a process that requires nimble fingers and/or decent fingernails, you can step up or down one notch in bass, as well as up two notches or down one notch in treble. The treble tips are molded clear or black tubes that fit into the silver earphones’ fronts, while the bass ports are flat panels that slide into the earphones’ backs. Once properly attached, the parts are not likely to fall off, but between their tiny sizes, the risk of improper attachment, and the lack of an included way to store the spare parts while in the explanatory card, there is a very good chance that you’re going to lose something in this kit unless you’re really conscious and capable of avoiding that mistake.
The good news here is that Sleek Audio’s do-it-yourself concept works, albeit subtly, to let you customize the sound that’s coming into your ears. In our testing, SA6’s standard three treble tubes provided modestly apparent changes to the earphones’ high-end response, while the extended high frequency tips brought treble into the sharp, “slightly too much” range; these tips were apparently added by Sleek to the package after the rest of its contents were designed.