I am quite amazed about your statement. Since the first day of my defy ownership, I have been worrying about the poor sound quality compared to my previous Sony Ericsson P1. Since the earphones have a cheap (IMO) feel to them, and dont fit me well either, I decided to hunt for a replacement.
I grabbed some Sony DR-EX39PP earphones, but found that even worsened the situatiuon. I also tried my wife's Defy (yes, I was once quite excited about this device), but hers isn't any better.
I have to turn volume all the way up to get a decent sound level, and the sound itself is thin and like metal. Using PowerAmp even lowers the available volume, and doesnt improve the sound much.
All in all NOT really usable, IMO. On my next android device purchase, I'll make sound quality a high priority item which I will be checking closely. The defy is not a candidate in that race, IMO.
just my opinion, for a balance