Headphone Reviews

Sound Quality
No doubt, this is a bass heavy headphone made for the kids that like the thumping bass, and they're gonna get it. These cans put out plenty of lows. While I found the impact of the bass good, and the extension into the lowest octaves good as well, they did have a somewhat murky bloated sound in the upper-bass. That said, the power handling of these cans is quite good and those looking for slamming lows might find them attractive.

While the treble was significantly lower in level than the bass, it's clean and quite natural. I'm quite averse to artificial sounding highs, and I thought the Tracks did a pretty darn good job in this area.

While the highs and low are pretty good with the Tracks, the mid-range has some serious trouble. While listening to pink noise, I readily detected a significant portion of the mids have gone missing. On some songs the vocals seem very recessed, in fact, at one point I had to check and see if the headphone plug was fully inserted as sometimes when not fully inserted you get a difference signal that tends to remove the center information leaving the vocals sounding low in level and hollow.

On some contemporary music tracks (trace, electronica, dubstep) this unevenness of the mids wasn't quite as noticeable as very often these genres are so artificial there it's hard to tell what's normal. But with acoustic jazz, chamber music, and vocals a significant unfaithfulness of the mids was readily apparent.

Measurements

Well ... there you have it. Right smack dab in the middle of the mid-range a fairly deep and well defined notch is readily apparent in the frequency response. If the notch wasn't there, I'd say this was a pretty respectable showing for a bass heavy can with a warm and fairly linear frequency response, but it is there, it is deep, and it was easily heard during listening tests.

Notice also how the THD+noise plots show a rise in distortion which coincides with the mid-range notch, I suspect this is indicative of the bloaty sound I heard, though I heard it as lower in frequency. Otherwise the THD is fairly low, and the 100dB plot being significantly lower in level than the 90dB plot indicate good power handling capability. I did think they played pretty clean at loud levels. Low THD below 100Hz and 30Hz square wave top remaining above zero indicate punchy, tight bass. The measured performance here seems slightly better than what I heard.

Even though the 300Hz square wave is severely misshapen due to the mid-range notch, the leading edge and first overshoot is nicely controlled, as is the impulse response, which backs up the listening test experience of a substantially responsive and clean treble response.

Impedance response shows a roughly 60 Ohm impedance which varys little over frequency; these cans should keep their character regardless of source output impedance. With 42mVrms needed to achieve 90dB, these headphones will be driven to fairly loud levels on portable devices. The isolation is modest at -11dB broadband; the Track will provide enough isolation for home and office and the moderate noise levels outdoors, but will not provide enough isolation for airplane and rail commuting.

Summary
I think SOL Republic has made a valiant first attempt with the Tracks. There is a lot in these headphones to admire at this price point. It ticks all the boxes nicely with excellent styling, build quality, and ergonomics.

While I think think they've also done a good job sonically in the bass and treble, the mid-range notch and recessed vocals just doesn't cut it, and this fatal flaw looses my recommendation. However, I think there will be a lot of folks who will get these cans and enjoy them for their big bass and clear highs. My recommendations for a low-cost, bass-heavy headphone would be the Sony MDR-XB500 and the Skullcandy Hesh 2 (not the Hesh, which don't sound nearly as good).

It really bums me out, these show a great deal of promise. So close, so close, and yet so far away. Oh well.

Resources
SOL headphones are not the standard fair at Head-Fi, but there are a few threads here, here, and here.
SOL Republic website and Tracks product page.