Being an owner of HD-439 (and HD-449) I can say this: Anyone who hasn't tried the bass mode but with ALL THREE HOLES OPEN, really miss a lot from this headhpone! It becomes a new set altogether. The bass may be much more, but the mids and highs are better than when you keep other holes closed. The complete removal of the tape releases the HD-439 full potential, I would suggest to everyone to go ahead and try it! I know everyone says it is too much, but after trying it I prefer it over any other hole-combination. I also tried a thinner fabric to cover all 3 holes, much better than the default tape, but something was still missing. After I released it, the sound is just perfect!
Of course, I would STRONGLY recommend it for this topic as a BASS headphone! After the bass mode, of course, otherwise it is just a warm, mid oreiented headphone with a sense of "hidden" bass. Indeed...
Now, if one needs better quality, you can try the HD-449 with the 3-hole open bass mode. This set, is better than HD-439, but lacks some bass, or overemphasises the other frequencies. That is without the mod, of course ;)
Edited by pouskidis - 3/30/13 at 12:00pm