Sennheiser HD 660S2 headphones offer more high-end low end

Circumaural Open-back Headphones with 300-ohm Impedance and 8Hz-41.5kHz Frequency Response

Sennheiser HD 660S2 Open-back Headphones

Sennheiser HD 660S2 review: I'm an open-back believer

Sennheiser HD 660S2 review: Legendary reference cans at a high price

Sennheiser HD 660S2 – Elise Audio

Sennheiser HD 660S2 review: Legendary reference cans at a high price

Sennheiser HD 660S2 Dynamic Headphones - Magnificent Musicality — Audiophile Heaven

Sennheiser HD 660S2 Dynamic Headphones - Magnificent Musicality — Audiophile Heaven

Just got the HD660s2! EQ recommendations needed! : r/headphones

Sennheiser HD 660 S2 Headphones, Audiophile, Headphones, Open Back Headphones

Sennheiser HD660S2: A Richer Experience

Audeze MM-100 & Sennheiser HD 660S2 Two Affordable Open-Back Headphones!

Sennheiser Consumer Audio HD 660S2 - Wired Audiophile Stereo Headphones with Deep Sub Bass, Optimized Surround, Transducer Airflow, Vented Magnet System and Voice Coil – Black : Electronics