The Sennheiser HD 650s are a high-end set of over-ear headphones. The HD 650s feature an open-backed design, which aims to bring a much more open, airy quality to their playback compared to closed-back designs. The downside to this style is poor isolation and playback that will be audible to those around you. This quality makes the HD 650s ideal for a private listening session at home, where users will be able to reap the benefits of the open-backed design while not suffering from any of its downsides.
The Sennheiser HD 650s are officially priced around $500, but conscientious shoppers can find them at a dramatically reduced price.