Sennheiser HD 650 vs Sennheiser HD 6XX

The Sennheiser HD 6XX are a revision of the Sennheiser HD 650 that are only available through the Drop website. There hasn't been a change in driver structure, and both headphones sound fairly neutral. However, the HD 6XX have a more consistent audio delivery, most likely due to their higher clamping force. While both headphones lack thump and rumble due to their open-back design, the HD 6XX have better bass accuracy. They also come in a dark blue colorway instead of black.