Performance

Judging the performance of headphones is always a hard thing to do because there are no real benchmarks you can put them through, at least non that will give a definitive answer. In order to test the capabilities of the SA6s I spent a lot of time trying out all of the different combinations on my different listening rigs. As far as comparison goes these in-ears will be going up against my main earphones which are: Westone UM1 & UM2, Ultimate Ears Super.fi 3 Studios, V-Moda Vibes. I also have a lot of big headphones, but those are only used as reference with regards to sound characteristics and are not used as direct comparisons since they are a completely different type of headphone mainly aimed at home listening.

My primary in-ear rig is my Cowon iAudio i7 DAP which is capable of playing lossless encoded files. Besides that I also have a Marantz CD6002 CD player and a Total BitHead which I have reviewed on a previous occasion. For all of my tests on the BitHead the gain was set to "low" since these earphones are extremely efficient.

To start out with I had the normal bass port and normal treble tube installed in the SA6s. The sound was extremely clean and the sound was very balanced with a slightly muffled treble. It was by no means a sparkly treble or anything of the sort. The bass was really tight and perhaps even tad a underwhelming, but again the bass definition was extremely good. You are able to hear every little stroke on the bass and every little thing going on in the bass department. Even with more different types of instruments the separation was really good. With the equal or minus bass ports installed the bass is a bit anemic and the lower register is a little depressing because it does not have the right amount of power. I am by no means a basshead, but the bass is where the beat of the music is and therefore an essential part of a good listening experience. The type of music I normally listen to ranges right from rock to trip-hop and therefore both a clean and powerful bass is a good thing.

Testing the bass performance of these earphones was very pleasurable experience. I went through all the ports and made notes about the sound change they made. My primary bass track is Massive Attacks "Angel" which features a lot of intense and textured bass. Sometimes having a lot of bass deprives the midrange a bit, with regards to the SA6s, even with the maximum bass ports on it still retains a good balance for most types of music and is by no means invasive or bloated. The bass performance of the SA6s is staggering, it is very clean and fast and extends quite nicely. The only IEM in my possession that can match the SA6's performance in that part of the spectrum is the Westone UM2 which is a dual driver earphone, and still the SA6 has the edge when it comes to conveying subtle details.

When it comes to the midrange the Sleek-Audio SA6s are no let down either. Where the bass is good the mids are incredible. The earphones are really good at making a natural reproduction of vocals. This cannot be emphasized enough, a good and faithful midrange reproduction makes all the difference between a good and bad pair of headphones. The midrange on the SA6s is very detailed and sounds clean and does not color the music that much, although it is a bit on the warm side. The general sound of the SA6s is lukewarm, but not anywhere near dull. The midrange does not change all that much depending on what treble tube or bass port you choose which just goes to show that the idea behind the tuning ports works well in practice as well as in theory.

The treble is probably the place where the Sleek-Audio SA6 excel the most. They have an insane extension while still not sounding harsh or sibilant. I listened to some string quintets on these earphones and they are only the second earphones I have listened to that made it worthwhile to listen to. The very good definition and natural highs made it stand out and made most classical pieces sound very good. I tried out the different treble tubes and they did not alter the performance, just the amount of amplification of the high tones. Even with the equal treble tube it did not sound muffled. It just sounded naturally dampened or perhaps a bit more distant.

Overall sound quality does improve noticeably according to what source you run them off. I tried using my BitHead at low gain thinking that it maybe could help widen the sound stage, but it really did not change things enough to justify the bulk of carrying it around. When hooked up directly to my Marantz CD6002 with a 1/8" to 1/4" adapter it became clear that the SA6s are a very revealing pair of in-ears. They do not add anything that is not there in terms of sound stage or airiness, but they are very good at bringing out the small details in the music and the background strokes and details.

In the end the configuration I swapped back to was with both the maximum bass and treble ports installed. I think it adds the right sparkle and the correct amount of bass for my needs. Each person probably feels that different combinations do it for them, and that is probably the main selling point with these earphones. The funny thing is that even with the possibly most imbalanced setup the resolution is still impeccable and the bass definition is spot on. What strikes me as crazy is that the resolution throughout the range is just amazing. After having listened to the earphones intensively for the last week or so they never cease to amaze me.

From a perspective of noise attenuation, these earphones are some of the best I have tried to date with its Westone competitors and Ultimate Ears alternatives. When it comes to dealing with microphonic noise these are on par with the Westone earphones I have recently reviewed and perhaps a bit better in some circumstances, i.e. the cable is not braided and therefore you do not notice it as much when they rub over a edge.

Durability

The build quality of the Sleek-Audio SA6 is really good. The only part that is prone to breaking is in my opinion the treble tube assembly because the darn things are so hard to pull out. Each time I swapped tubes it took me an awful lot of time and a lot of frustration. It is generally a good thing that the construction is durable and fits together nicely, but with no removal tool it is just a painstaking procedure trying to remove the treble tubes. Every other aspect of the SA6 is well thought out and the construction quality is right up there with the very best.

Sleek-Audio is aware of the problem and are working on a device that allows users to remove the treble tubes in a more safe and easy manner.