Designed as studio headphones for audio professionals, Equation Audio’s RP-21 has emerged as an underground favourite among music lovers, known for its top-notch sound at an affordable price. Equation Audio is focused on sound quality above all else, and designed the RP-21 to be elegantly simple, comfortable and robust to withstand the rigours of professional use. The RP-21 has a pleasingly warm midrange, revealing yet non-fatiguing high end, and a superb low-end that gives music a rock-solid foundation. Unlike many high-end headphones in the market, the RP-21′s relatively high sensitivity (100dB) means you can choose to use them direct from your iPod, or though a separate headphone amplifier.