To my ears Radiopaq's Rock earphones have a more amenable tuning. The frequency response is - supposedly - tuned to offer better response both low down and at the top end, with reduced distortion. You'd have to be mad not to notice there's definitely plenty of bass, although thankfully not quite to the point of being overwhelming.
Vocals, such as Matt Bellamy's on Muse's In Your World or Freddy Mercury's on Queen's Don't Stop Me Now, stand out. Occasionally this vocal presence can come at the expense of seeming a little out of the mix. If I was feeling harsh I might say Radiopaq had over-tuned its Rock earphones, but it's not quite frequent enough an issue to annoy.
I was less convinced by the reproduction of Frank Sinatra's I've Got You Under My Skin and Tchaikovsky's 4th didn't sound much better on the Rock 'phones than the Pop, coming across tainted and unbalanced.
Inevitably, testing the Classical earphones required breaking out the Wagner to pleasing results. Gotterdammerung and, of course, Die Walkure were both presented in a perfectly pleasant, balanced and precise manner. Lower-pitched brass and strings might benefit from a touch more bass, as was also evidenced in Beethoven's Ninth. The overall balance of the Classical earphones is definitely the most genre-specific, too, with anything not comprised of a large variety of sounds coming across flat and lacking presence.
The Jazz earphones are a perfect excuse to give my Louis Armstrong collection a much-overdue airing and it was worth the effort. Radiopaq claims its tuning here offers detail, range and balance and I'm happy to agree with that - Mac the Knife and What a Wonderful World were pumped out with due aplomb. Moving on to Robbie Williams' surprisingly brilliant version of Jerry Jeff Walker's Mr. Bojangles and there's little to complain about with strings, brass and, of course Williams' vocals all sounding bright and warm. I think the Jazz earphones are the best with other music, too. Bass is perhaps a tad lacking for some rock or pop tracks, but classical music doesn't sound any worse with the Jazz than the Classical earphones (and vice versa it should be said).
For their price, the audio quality isn't bad on any of the Custom Tuned Earphones; with the genre of music they're tailored to. However, despite what Radiopaq says none of the earphones are particularly great if you want to listen to music for which they aren't tweaked for, while rival products, such as the Shure SE102 or Klipsch Image S4 earphones sound better across a broad range of genres.