We're back at it again today with a close look at a portable set of headphones in the mid-tier price category - the Sennheiser HD238 headphones. Retailing at $139, they are marketed as providing "high-quality lifelike stereo sound" with an open-back design, all without sacrificing comfort. We test these claims and see how they compare to other similarly priced headphones for iPods and other portable music players.