Sleek Audio's Web site is peppered with reminders that it makes no sense to listen to your expensive MP3 player through a "$5 pair of earbuds." I couldn't agree more, and, at $249.99 list, the SA6 from Sleek Audio is certainly an upgrade! Sleek Audio, which started off as a hearing-aid manufacturer, takes an admirable step most companies don't: The manual includes in-depth explanations of safe listening levels and hearing-loss risks. Also included with the earphones are treble and bass "tuning ports" that alter the audio output to suit different tastes and eardrums. These are not the most fantastic earphones I've heard, but for the price, they offer a customizable, fairly flat response. If you're seeking a truly flat response, the best choice is either Etymotic's $400 ER-4P or Ultimate Ears' $900 custom-fit UE 10 Pro. If $250 is more what you had in mind, the SA6 can do battle with similarly priced Shure and Ultimate Ears models and is customizable in a way most earphones are not.