Sennheiser HD 660 S vs Sennheiser HD 490 PRO

The Sennheiser HD 660 S and the Sennheiser HD 490 PRO are similar open-back, over-ear headphones. The HD 490 PRO have a PRTF that's slightly more aligned with the response of an angled reference speaker. They're also designed for audio professionals and come with two sets of pads: one for producing and one for mixing. While the HD 490 PRO are the superior headphone, the HD 660 S can be found at a slightly lower price point and are still a worthy set of well-made audiophile headphones.