In-Ear Headphones Face Off Page 5


Key Features
• Accessories: 3 pair ear tips, 4 treble tuning tips, 3 bass port plugs, interchangeable cable, removal tool for ports/tips, cleaning tool, plastic hard case • Impedance/Sensitivity: 50 ohms/110 dB/mW

Sleek Audio SA6

An engineer and acoustic scientist who spent more than 30 years designing hearing aids before turning his expertise to music founded Sleek Audio. Based on a single full-range armature design, the SA6 comes with the unique ability to fine-tune both the bass and treble to suit your musical tastes. Each compact triangular earpiece has a port on the back that fits one of three different bass plugs, while replacing the ear-tip nozzle with one of the three supplied filters will trim the treble. A special tool allows you to grab and remove these tiny pelletlike attachments. Sleek says the attachments will swing the bass + 6 dB or - 6 dB from flat-frequency response in the 20- to 200-Hz range, or bring the treble down in a series of 3-dB increments between 10 kHz and 12 kHz. The 3-dB down treble tip is the factory default.

Fit and finish on these tiny 'phones is good, and they include removable earpiece wires that attach with small snap-in pin connectors to allow replacement in the event of a failure. This arrangement also permits connection of an optional wireless kit that uses technology licensed from Kleer Corporation. The lightweight receiver attaches directly to the earpieces and hangs around your neck, while the dongle transmitter plugs into your player. Although I evaluated the SA6 with a wired connection, I also tried out the wireless system and experienced no sound degradation. Also, its signal remained robust up to 40 feet and one floor away from the transmitter. The wireless kit sells for $170 separately or can be bundled with the SA6 for a total of $320 - just $70 more than the price of the 'phones alone.


After some trials, I settled on both the + bass port and the + treble tip for my evaluation. The + bass port extended useful low-end response to about 25 Hz before dropping off significantly, compared with a rolloff below 35 Hz for the default port. The + treble tip also added a little more definition to instruments like struck cymbals, but without making them sound edgy or strident.

The instrument tracks from Sound Check suggested promising things from the SA6. Piano came across with big, full notes that floated nicely in space, the a cappella voice had good body and dynamics that tracked the signal peaks, and the flute's excellent detail was evident in the warbling notes and the musicians' breathing. The violins, meanwhile, were notably smooth, and came across with strong dimensionality and clear delineation between the left and right sections.

Moving on, I found that lead vocals on "Wishing Well," "I Can't Stand the Pain," "The Gypsy," and "Union Dues" were very naturally presented and true to the recordings, with no artificial emphasis that brought them forward in the mix or made them sound more etched. Bass delivery, while not the best in our test, was better than average, and with the SA6's + bass port plugged in, it was able to easily convey the Babatunde Olatunji drum track. The demanding Firebird sounded open and spacious, and the instruments came across with excellent body and detail. The SA6 demonstrated very good dynamic range but couldn't comfortably play as loud as the better 'phones on this track; I had to scale back the volume a bit to get through the loudest crescendos without overloading them and hardening the sound.


Sleek Audio's SA6 is a very smooth-sounding, wellbalanced earphone with clean mids and highs, average to above-average dynamics, and aboveaverage bass. It also offers truly useful options to fine-tune its sound and to go wireless, and it has a very attractive price tag.