Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.

What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.

Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.

What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.

Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.

What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.

Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.

What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.

Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.

What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.