Home Headphones Sennheiser HD 660S Sennheiser
Released October 2017
The HD 660S are Sennheiser's 2017 open-back wired headphones from the HD 600 series, a successor to the HD 650 with new transducers and a lower 150-ohm impedance, suited to home listening.
Compare with another pair of headphones Compare with… Audio-Technica ATH-ADX5000 (2017) Audeze LCD-2 Classic (2017) HIFIMAN SUSVARA (2017) K361 (2019) K371 (2019) K872 (2016) K712 PRO (2013) K702 (2008) K701 (2005) Space 2 (2026) AeroFit 2 Pro (2026) Liberty 5 (2025) AeroFit 2 (2024) Liberty 4 Pro (2024) Space One Pro (2024) P40i (2024) Space One (2023) Liberty 4 NC (2023) Space Q45 (2022) AirPods 5 (2026) AirPods 5 with Wireless Charging Case (2026) AirPods Max 2 (2026) AirPods Pro 3 (2025) AirPods 4 (2024) AirPods 4 with Active Noise Cancellation (2024) AirPods Max (USB-C) (2024) AirPods Pro 2 (2023) EarPods (USB-C) (2023) AirPods (3rd generation) (2021) AirPods Max (Lightning) (2020) AirPods Pro (1st generation) (2019) AirPods (2nd generation) (2019) AirPods (1st generation) (2016) EarPods (Lightning Connector) (2016) EarPods (3.5mm Headphone Plug) (2012) MM-100 (2023) Maxwell (2023) MM-500 (2022) LCD-5 (2021) LCD-GX (2019) LCD-X (2013) LCD-XC (2013) LCD-2 (2009) ATH-R50x (2025) ATH-R70x (2015) ATH-M40x (2014) ATH-M50x (2014) Beats 360 (2026) Powerbeats Fit (2025) Powerbeats Pro 2 (2025) Solo Buds (2024) Solo 4 (2024) Studio Pro (2023) Studio Buds + (2023) Fit Pro (2021) Studio Buds (2021) Beats Flex (2020) Powerbeats (2020) (2020) Solo Pro (2019) Powerbeats Pro (2019) Studio3 Wireless (2017) BeatsX (2017) urBeats3 (2017) Powerbeats3 Wireless (2016) Beats EP (2016) Solo3 Wireless (2016) Solo2 Wireless (2014) Solo2 (2014) Powerbeats2 Wireless (2014) Studio Wireless (2013) (2013) Tour2 (2013) Studio (2013) (2013) Executive (2012) urBeats (2012) (2012) Wireless (2011) (2011) Mixr (2011) Solo HD (2010) Beats Pro (2010) Powerbeats (2010) (2010) Solo (2009) (2009) Studio (2008) (2008) Tour (original) (2008) AMIRON 100 (2024) DT 1770 PRO MKII (2024) DT 770 PRO X Limited Edition (2024) DT 1990 PRO MKII (2024) Xelento remote (2nd generation) (2022) DT 700 PRO X (2021) DT 900 PRO X (2021) T1 (3rd generation) (2020) T5 (3rd generation) (2020) DT 1990 PRO (2016) DT 1770 PRO (2015) DT 770 PRO (1985) DT 990 PRO (1985) QuietComfort Headphones (2nd Gen) (2026) QuietComfort Ultra Headphones (2nd Gen) (2025) QuietComfort Ultra Earbuds (2nd Gen) (2025) QuietComfort Earbuds (2024) Ultra Open Earbuds (2024) QuietComfort Ultra Earbuds (2023) QuietComfort Ultra Headphones (2023) QuietComfort Headphones (2023) QuietComfort 45 (2021) Noise Cancelling Headphones 700 (2019) QuietComfort 35 II (2017) QuietControl 30 (2016) QuietComfort 35 (2016) QuietComfort 25 (2014) QuietComfort 20 (2013) QuietComfort 15 (2009) QuietComfort 3 (2006) QuietComfort 2 (2003) QuietComfort (2000) Px8 S2 (2025) Px7 S3 (2025) Pi8 (2024) E3 (2023) EXPANSE (2022) STEALTH (2021) AEON 2 Noire (2021) Bathys MG (2025) Azurys (2024) Hadenys (2024) Utopia (2022) Clear MG (2021) Clear Mg Professional (2021) Celestee (2021) Radiance (2020) Stellia (2019) Elegia (2018) Elear (2016) Pixel Buds Pro 2 (2024) Pixel Buds Pro (2022) GS1000 Classic (2026) Hemp Classic (2026) RS1 Classic (2026) SR325 Classic (2026) SR80 Classic (2026) SUSVARA UNVEILED (2024) ANANDA NANO (2023) Arya Organic (2023) HE1000 Stealth Magnet (2023) SUNDARA Closed-Back (2022) ANANDA Stealth Magnet (2022) DEVA Pro (2021) Edition XS (2021) Arya Stealth Magnets (2021) HE400se (2021) HE6se V2 (2020) SUNDARA (2018) Live Beam 4 (2026) Live 780NC (2026) Tune 780NC (2025) Sense Pro (2025) Tour One M3 (2025) Tour Pro 3 (2024) Live Beam 3 (2024) Live 770NC (2023) Tune 770NC (2023) Tune 720BT (2023) Live Pro 2 TWS (2022) 99 Classics (2nd Gen) (2025) POET (2025) Liric (2nd Gen) (2024) Empyrean II (2023) 109 PRO (2022) Elite (2021) Ear (3) (2025) Headphone (1) (2025) Ear (2024) Galaxy Buds4 (2026) Galaxy Buds4 Pro (2026) Galaxy Buds3 Pro (2024) Galaxy Buds2 Pro (2022) MOMENTUM True Wireless 5 (2026) MOMENTUM 5 Wireless (2026) HDB 630 (2025) HD 550 (2025) HD 505 (2025) HD 620S (2024) ACCENTUM Plus Wireless (2024) HD 490 PRO (2024) HD 660S2 (2023) IE 200 (2023) MOMENTUM 4 Wireless (2022) IE 600 (2022) HD 400 PRO (2021) IE 900 (2021) IE 100 PRO (2021) IE 300 (2021) HD 560S (2020) MOMENTUM 3 Wireless (2019) HD 820 (2018) HD 599 (2016) HD 800 S (2016) MOMENTUM 2 Wireless (2015) MOMENTUM (2012) HD 800 (2009) HD 280 PRO (2003) HD 650 (2003) HD 600 (1997) HD 25 (1988) Ace Ultra (2026) Ace (2024) WH-1000XM4C (2026) WH-CH730N (2026) 1000X THE COLLEXION (WH-1000XX) (2026) WF-1000XM6 (2026) INZONE H9 II (2025) WH-1000XM6 (2025) WF-C710N (2025) LinkBuds Fit (2024) LinkBuds Open (2024) MDR-M1 (2024) WF-C510 (2024) ULT WEAR (WH-ULT900N) (2024) INZONE Buds (2023) INZONE H5 (2023) WF-1000XM5 (2023) MDR-MV1 (2023) WF-C700N (2023) WH-CH520 (2023) WH-CH720N (2023) INZONE H3 (2022) INZONE H7 (2022) INZONE H9 (2022) LinkBuds S (2022) WH-1000XM5 (2022) WF-C500 (2021) WF-1000XM4 (2021) WH-1000XM4 (2020) WH-CH710N (2020) WF-1000XM3 (2019) WH-CH510 (2019) WH-1000XM3 (2018) WF-SP700N (2018) WH-CH700N (2018) WF-1000X (2017) WH-1000XM2 (2017) MDR-1000X (2016) MDR-1A (2014) MDR-1R (2012) MDR-7506 (1991) MDR-CD3000 (1991) MDR-R10 (1988) MDR-V6 (1985) Arctis Nova Pro Omni (2026) Arctis Nova 5 Wireless (2024) EAH-AZ100 (2025)
Type Over-ear
Noise cancelling No
Battery –
With case –
Best codec Wired
Weight 260 g What reviewers say Reviewers agree the headphones are light and comfortable for hours, with an excellent, involving sound. SoundGuys found them only a small step up from cheaper Sennheisers and a touch less analytical than the HD 600, Trusted Reviews found the tuning favours enjoyment over strict neutrality, and Louder wanted more bass.
From trustedreviews.com , soundguys.com and loudersound.com
Sound
Type Over-ear
Noise cancelling No
Driver size 38 mm
Back Open
Impedance 150 ohms
Bluetooth codecs None (wired)
Drivers Dynamic, open, diffuse-field equalised; 42 mm transducer with 38 mm diaphragm and aluminium voice coil; ventilated drive unit with steel mesh; transducers matched in pairs; 9 – 41,500 Hz (–10 dB); 104 dB SPL at 1 kHz (1 Vrms); THD ≤ 0.04% (1 kHz, 100 dB); max. 500 mW long-term input power Battery
Listening time (maker's claim) No battery (wired) Design
Weight 260 g
Headphone cable Yes
Fit and ear tips Over-ear (circumaural), open-back; contact pressure approx. 6.0 N ± 1.0 N; replaceable ear pads
Works with Detachable 3 m OFC cables with gold-plated 6.35 mm unbalanced and 4.4 mm balanced plugs; 6.35 mm to 3.5 mm adapter; optional CH 650 S cable with 4-pin XLR sold separately
In the box HD 660S headphones, cable with 6.35 mm plug, cable with 4.4 mm balanced plug, 6.35 mm to 3.5 mm adapter, instruction manual, storage box Pros and cons Pros + 150-ohm impedance is easier to drive than the 300-ohm HD 600 and HD 650+ Both 6.35 mm and balanced 4.4 mm cables in the box+ Light at 260 g; 9 Hz to 41.5 kHz (–10 dB)Cons − Firm contact pressure of about 6.0 N− Open back leaks sound and lets outside noise inNewer model: HD 660S2 .
