Sennheiser HD 560 S

Advantages

• ✓HD 560S is lighter (240 g vs 260 g) and easier to drive from low‑power sources.
• ✓Deeper bass extension down to 20 Hz provides more controlled low‑frequency response.
• ✓Lower total harmonic distortion (<0.05% vs higher in HD 650) yields cleaner sound.

Disadvantages

• ✗HD 560S lacks the warm, forgiving mids that many users prefer in the HD 650.
• ✗Both are open‑back, so neither offers isolation; HD 560S does not improve on this.
• ✗HD 560S may be perceived as less musical by listeners who favor the HD 650’s signature sound.

Advantages

• ✓HD 560S is lighter and has a lower impedance (120 Ω vs 150 Ω), making it more portable and easier to drive.
• ✓Ultra‑low distortion and a polymer‑blend driver give slightly cleaner reproduction than the HD 660S.
• ✓Price point is generally lower, offering better value for a neutral reference headphone.

Disadvantages

• ✗HD 660S offers a semi‑open design with better isolation than the fully open HD 560S.
• ✗HD 660S has a slightly brighter treble that some users prefer for analytical detail.
• ✗Both lack folding designs, so portability remains a shared drawback.

Advantages

• ✓HD 560S is lighter (240 g vs 370 g) and has lower distortion, providing a cleaner soundstage.
• ✓Easier to drive from portable sources due to higher sensitivity (110 dB/V vs 102 dB/V).
• ✓More neutral tuning makes it better suited for reference work than the brighter DT 1990 Pro.

Disadvantages

• ✗DT 1990 Pro offers swappable ear pads and a more analytical treble that some professionals prefer.
• ✗DT 1990 Pro includes a more robust build with better isolation despite being open‑back.
• ✗DT 1990 Pro’s higher price may be a barrier for budget‑focused users.