The Sennheiser HD 660S2 is 38% off, and it’s the audiophile headphone upgrade I’d recommend without hesitation

By Omair Khaliq Sultan Published March 18, 2026

The Sennheiser HD 660S2 has been on my radar as a recommendation for anyone looking to step up from the HD 650, and at $419.81 it’s now $260 off its $679.95 list price. That’s a 38% cut on what is arguably Sennheiser’s most accomplished open-back headphone in this range, and it brings it into a price bracket that’s very hard to argue with.

The HD 660S2 is a direct evolution of the HD 650 lineage, but the most meaningful change is the bass extension. Sennheiser redesigned the transducers to reach lower frequencies with more authority, addressing the one area where the HD 650 left some listeners wanting more. The result is an open-back headphone that retains the warm, natural midrange the 650 is known for while adding genuine weight at the low end.

Like its predecessor, the HD 660S2 is a 300-ohm design, so you’ll get the most out of it with a dedicated headphone amplifier or DAC. That said, it scales well with better source equipment over time, making it a headphone worth investing around rather than one you’ll replace. The open-back construction delivers a wide, natural soundstage that closed-back designs consistently struggle to replicate, and the imaging is precise enough to make it a useful tool for mixing and critical listening as well as casual use.

Build quality follows the same template as the broader HD 600 family: lightweight, replaceable ear pads, a detachable cable, and a headband that distributes pressure evenly for long listening sessions. It’s not a flashy design, but it’s built to last and easy to service if something wears out.

At $679.95, the HD 660S2 sits at the upper end of what most people would consider accessible audiophile territory. At $419.81, it lands in a bracket where the competition gets considerably thinner. The Beyerdynamic T1 and Audeze LCD-1 both occupy similar territory, but neither offers the same combination of bass extension, natural tuning, and repairability that the 660S2 brings to the table. If you already own an amp or DAC, this is a straightforward upgrade decision.

The Sennheiser HD 660S2 at $419.81 is a rare deal on a headphone that represents the best of what Sennheiser does. The extended bass response, refined acoustic tuning, and open-back soundstage add up to a listening experience that justifies every cent, and the $260 discount makes it one of the more persuasive audiophile headphone deals available right now.