Disclaimer: I purchased this headphone in 2004 from an UK distributor. The model was already discontinued in 2000, so the price was £63 + shipping. Not a bad deal, I guess.
MDR-R10, also known as the king of headphones to SONY enthusiasts, debuts in 1988. And the economic downgraded version, MDR-CD3000, follows right after along with other introductory models. These are known as the first generation CD series. SONY have had a great success with the first generation, but none of the headphones really sound like R10; they are all too bright! And finally, in 1996, the second generation, starting with MDR-CD1700, equipped with 50 mm bio-cellulose & Vectran composite drivers, rocks the scene with its neutral tonality close to that of R10.
PRO: MDR-CD1700 is accurately diffuse-field calibrated, with a downward slope of -2 dB per octave starting from 3 kHz. Since the frequency response corresponds to the tolerance limit of ITU-R BS.708, it can be assumed that the headphone is designed for studio-monitoring. Due to its large driver size, CD1700 has a large sweet spot. This yields a very constant spectral balance regardless of where the headphone is placed on the head. Thnx to the open-air/semi-open back design, the headphone's transient characteristic is near instantaneous.
CON: Since the velour stock pads introduce a characteristic leak on usage, the low-frequency bandwidth suffers greatly.
ON SECOND THOUGHT #1: I've heard MDR-R10 before, and honestly, CD1700 definitely shares some common musicality with the king. However, these two headphones are simply incomparable when it comes down to the overall sound quality. An heir is an heir, but that is about it.