Summary of review:
* Retail price: $39.99
* Overall sound clarity: excellent
* Fit: average at best
I purchased a set of Polk Audio UltraFit 500 Sport Headphones just a few days ago. The retail price was $39.99 at a Fry's Electronics store. Although the box had a flap that opened to see the headphones, it did not--to the best of my knowledge--include any specifications regarding impedance or frequency response.
The sound source I used was MP3, 128 kbps. While not the highest quality, it was still a test for the headphones. Overall clarity of the sound was excellent--though the bass was not pronounced (when compared with something like a Sony MDR-J10 or MDR-J11 or a Koss The Plug type of earbud headphone), the bass was not overexaggerated, the midrange was clear, and the highs were not attenutated or too much. For more bass, just select a bass EQ setting--I found that the clarity will still be there for the mids and highs. Still, I was expecting just a bit more bass output than what I got from the headphones just out of the box--especially, techno style bass pitch bends downward seemed to attenuate the bass sooner than expected for a headphone in that price range.
Regardless of the lack of specifications, I think these are very good headphones for playing loud, without any distortion. At the same time, they can be played softly as well, with no significant loss of clarity. But I think Polk does need to provide specifications, especially since others such as JVC, Sony, Philips, and others do provides specifications including impedance and frequency response.
Fit-wise, I am still trying to get it exactly right. It's not the silicone earpads that seem to be the problem, for me, it is the earclips. That said, I also do like the longer cables provided with the headphones, that connect right into the shorter cable built into the headphones.
In conclusion, I would recommend these headphones with but there are two issues I encountered: the earclips may not fit without some readjusting (for me, anyway) and that the bass is not as pronounced with compressed audio formats such as MP3 with no EQ set on an MP3 player.