The Diamond Rio 500 and today's D-Link DMP-100 both offer exemplary audio quality out of the box (we give the slight edge to the Rio 500), but they're limited in how much manipulation of the environment is possible by the user.

Diamond omits an EQ altogether in their Rio 500, in favor of basic "Bass and Treble" controls. The DMP-100 goes the other direction by offering no Bass or Treble controls, but instead providing four preset EQ modes that affect the music: EX-Bass, Classic, Jazz, and Pop.

We found we liked the "Classic" EQ setting the best with the DMP-100, it provided the most realistic depth and range out of the possible selections. Still, it doesn't match the joy of independent controls, which would offer hundreds of combinations to the listener versus four pre-set generalized settings.

Aside from our usual gripe about a non-controllable EQ, we found the overall quality and range of the DMP-100 to be fairly good. It falls into the general acoustic range of an inexpensive portable CD player, which is saying a lot about how far MP3 players have come.

We still herald the Diamond Rio 500 and RCA's Lyra as the best sounding MP3 portables that are currently available, but the DMP-100 is the closest challenger we've seen to the title yet. When Sony and Panasonic's MP3 portables arrive over the next three months they may topple the Rio 500 and Lyra from their throne, particularly if they deliver the sound quality that we heard from prototypes we listened to at last month's Consumer Electronics Show. The same goes for the Creative Nomad II MP3 player, which is also due to hit the market soon, it also delivered excellent sound quality in prototype form.

For now though, the Rio 500, Lyra, and D-Link DMP-100 all offer better than average sound quality, after a minute or so it's easy to forget that you're not listening to a MiniDisc or CD player.

As important as the audio quality level of the player itself are the earbuds that the manufacturer includes with the player. We always pay special attention to the bundled sets of earbuds that usually come with MP3 players, as a poor set can sabotage an otherwise good player while a good set can make the player rise to a new level.

The DMP-100's included earbuds are slightly above average in their precision level, with bass response being merely adequate while midrange and treble were strong points. This happens often in portable consumer electronic products as manufacturers bundle earbuds with smaller driver units that aren't capable of handling extreme bass amounts without distortion, even though the midrange and treble response is fairly sharp.

The earbuds contained within the DMP-100 package are good, although we felt there was an audible difference in bass precision by stepping up to our reference Sony MDR-E888 earbuds (MSRP $70). We test all earbuds against the flagship Sony MDR-E888s, to give us an idea how well "freebie" earbuds stack up to an expensive aftermarket set. As with any upgrade advice, try the DMP-100's stock earbuds first. If they don't put out enough bass for your needs, look to aftermarket earbuds that are within your price range for help.