Sennheiser HD 6XX Headphones Review

The Sennheiser HD 6XX are open-back headphones with the same design as the Sennheiser HD 650, but with a few minor differences. They're available in a midnight blue color scheme, unlike the gray-and-black Sennheiser HD 650. They have large, oblong ear cups with a metal grille on the outside to help protect the drivers.

These headphones are decently comfortable. They're lightweight, and the ear cups are well-padded, so they feel soft and comfortable against your skin. However, they clamp a bit tighter than the Sennheiser HD 650 and the Drop + Sennheiser HD 8XX, which can feel a bit fatiguing after long listening sessions. It's most likely because these headphones have new pads, though, as the padding can wear down and lower their clamping force over time. You can see the HD 6XX's pad condition here.

These headphones don't have any controls.

These headphones have poor portability. Like most over-ears, they have a big and bulky design, so they may not fit easily into your bag. They also don't fold into a more compact format, and they don't come with a case to protect them when you're on-the-go.

These headphones don't come with a case or pouch.

The Sennheiser HD 6XX have a good build quality. They feel very similar to the Sennheiser HD 650. They're mostly made of plastic, with a metal headband and metal grilles covering the ear cups. However, there isn't a lot of padding on the headband.

They're decently stable. They clamp tight on your head, and they should stay on your ears during casual listening sessions. However, they aren't designed for sports and may fall off your head during more intense physical activity. Also, the wire could potentially snag on something, which could pull the headphones off of your ears.

• Sennheiser HD 6XX headphones
• 1/8" to 1/4" adapter
• Detachable TRS audio cable
• Manuals

The Sennheiser HD 6XX have a very neutral, balanced sound profile that's suitable for listening to lots of different types of audio content. Like most open-back headphones, they lack some low-bass, which can be disappointing for fans of bass-heavy music genres like EDM and hip-hop.

These headphones are a revision of the Sennheiser HD 650 and are often compared in sound to them. However, when we originally tested both headphones, we noticed that they differed in frequency response. After closer examination, we noticed our HD 650 model, which was originally tested in 2020, had lots of wear and tear on the ear cup padding. It can affect their audio delivery as they may not be able to create a good seal or fit. As a result, we purchased a new pair of padding to check for differences between this model and the HD 6XX. Note that this padding isn't the same as the original padding. It appears that Sennheiser altered their manufacturing in 2021, and there have been reports that the new padding is rounder and a bit stiffer. First, we compared the 6XX's original pass with a new pass using the same pads. It helps us identify if the headphones' padding has worn down enough over time to change their sound. Then we replaced the HD 650's pads and compared them to the HD 6XX, which still have their original pads. After this change, the frequency responses look much more similar. It suggests that wear and tear over time can result in a change in clamping force and, ultimately, frequency response. If you notice that your unit's padding is getting softer or flatter, you can replace them by purchasing a pair directly from the manufacturer.

These headphones have impressive frequency response consistency. There's some inconsistency in the treble range, so their audio delivery can vary depending on their fit, seal, and positioning on your head.

They have good bass accuracy. Like many open-back headphones, their low-bass is underemphasized, so audio lacks deep thump. However, they can still reproduce punch and boom quite accurately.

These headphones have remarkable mid accuracy. The entire range is quite even and neutral, so vocals and lead instruments are clear and present in the mix.

These headphones have very good treble accuracy. Vocals and lead instruments are present and detailed, but the dip in the mid-treble can make sibilants like cymbals dull and lispy. However, their treble delivery can vary across listeners, so your experience may differ.

The Sennheiser HD 6XX have very good peaks and dips performance. Due to the dip in the low-bass, you don't feel the deep thumps, but the peak in the high-bass adds a boomy quality to the mix. The slight dip in the mid-mids may nudge vocals and lead instruments towards the back of the mix, while the peak in the low-treble can make those same instruments harsh and painful. The mid-treble is uneven, so sibilants like S and T sounds can be alternately dull or piercing.

The Sennheiser HD 6XX have excellent imaging. Their weighted group delay falls below the audibility threshold, resulting in tight bass and transparent treble. Also, the L/R drivers of our test unit are well-matched in amplitude, phase, and frequency response. As a result, objects like voices, instruments, and footsteps are accurately placed and localized within the stereo image. However, these results are only valid for our test unit, so your experience may vary.

They have a decent passive soundstage. The soundstage is natural and speaker-like, but you won't perceive it as being very large or located outside of the listener's head. Due to their open-back design, they have a more open and spacious soundstage than headphones with a closed-back design, but it's still not as wide or immersive as headphones like the Audeze MM-100.

These headphones don't have any virtual soundstage features.

The Sennheiser HD 6XX have an impressive weighted harmonic distortion performance. The frequencies fall within good limits, resulting in clean and pure audio reproduction.

These are the settings we used to test these headphones. Our results are only valid when using these settings.

The Sennheiser HD 6XX have terrible noise isolation due to their open-back design. They don't block out any sounds in the bass and mid-ranges, so you can hear the deep thump and rumble of bus or plane engines or chatter from people talking around you. While they perform a bit better in the treble range, you may still hear sounds like the hum of nearby AC units.

Due to their open-back design, they have awful leakage. They leak a lot of sound, and it's audible even in noisier settings like an office. It may be distracting for people around you. Also, the leakage is fuller-sounding compared to that of closed-back headphones and in-ears.

The Sennheiser HD 6XX don't have a microphone.

The Sennheiser HD 6XX don't have a microphone, so the recording quality isn't tested.

There's no microphone, so the noise handling isn't tested.

These passive headphones don't have a battery.

They don't have a companion app.

These wired-only headphones don't support a Bluetooth connection.

These wired-only headphones don't support any wireless connectivity.

The Sennheiser HD 6XX come with a long 1/8" TRS cable, but the cable doesn't have an in-line remote.

You can plug these headphones into your Xbox One controller, but they don't have a microphone, so you only receive audio.

The Sennheiser HD 6XX don't have a base or a dock.