The Sennheiser HD 650 deliver an excellent and open sound that's great for critical listening. They're comfortable and decently built but unfortunately, like most open critical listening headphones, they won't be suitable for more casual uses. They do not block any noise and they leak a lot so they're best used in isolation where you can really benefit from their sound quality.
The Sennheiser HD 650 are decently designed headphones with large comfortable earcups. They're not as tight on the head as the HD 600, which reduces the clamping sensation you feel during long listening sessions. Sadly, this also makes them slightly less stable on your head. They offer no audio control options, and they're also a bit too bulky and may require a bag to carry them around. Also, like most open-back designs, they will not be suitable for outdoor use.
The Sennheiser HD650 have the same design as the HD 600 with a few minor differences. They have a two-tone, dark gray and black color scheme with a glossy coating. The large open ear cups have a suede-like finish on the padding that gives these headphones a premium appeal. They do not look as eye-catching as the HD 600 because of their slightly bland color scheme, but the style will work for some.
The Sennheiser HD 650 are slightly more comfortable than the HD 600. Like the previous model, these headphones have large ear cups that fully encompass most ears. They are also covered in a suede-like fabric that feels good on the skin and adds to their overall comfort level. The headband design is better than the HD 600, it's not as tight, and it's better padded.
These headphones do not have any controls.
The Sennheiser HD 650 have an open-back design that makes them decently breathable. They still seal your ears within the ear cups which obstructs a good amount of airflow but thanks to their open back design and slightly porous earcup pads they do not get as hot as most closed back over-ear designs.
These headphones are not designed to be very portable. They're large and bulky and do not fold into a smaller format for transport or easy storage. They also don't offer a dedicated case or pouch to carry the headphones in, which is slightly disappointing. Although the box they come in could be a substitute for a case, it's too big and impractical for regular use.
The build quality of these headphones is above-average with a few minor flaws. It doesn’t feel as high-end as the HiFiMan Sundara or the Beyerdynamic DT 1990 PRO. The headband is the weakest part of their design. The metal frame is connected to the earcup by a fragile-looking joint that's susceptible to breaking under moderate physical stress.
The Sennheiser HD 650 are a little less stable than the HD 600 because they have less tension in the headband. They stay in place during casual listening sessions and are stable enough for some low-intensity, physical activity. However, they are not designed for sports, and the slightly looser headband may cause them to fall off your head if used while running. The detachable cable will also pull the headphones of your head before it disconnects from the ear cups, which is slightly disappointing.
The Sennheiser HD 650 is a very good sounding pair of open-back over-ear headphones. These headphones have a very good, consistent, and punchy bass, a great, well-balanced, and clear mid-range, and a very good treble. However, their bass lacks a bit of thump and is a little bit muddy, and their treble is slightly veiled. This makes them a very versatile pair of headphones that sounds great on classical, rock, folk, and other vocal-centric genres, but their sub-bass may be a little bit lacking for the fans of bass-heavy music. Additionally, they have very good imaging, but their soundstage is not as good as Sennheiser's larger headphones like the HD 800 S and the HD 700. Compared to the HD 600, the Sennheiser HD650 has a bit more sub-bass and sounds slightly veiled in the treble.
The bass of the Sennheiser HD 650 is great. LFE (low-frequency extension) is at 40Hz, which is good. Low-bass, responsible for the thump and rumble common to bass-heavy genres, is lacking by about 5dB. This will be noticeable, but subtle. Mid-bass, responsible for the body of bass guitars and punch of kick drums is within 0.3dB of our neutral target. High-bass, however, is overemphasized by almost 3dB, adding a bit of muddiness to the overall sound.
The mid-range is great. The response throughout the range is very even and flat, but consistently over out neutral target by about 2.5dB. This results in a clear and well-balanced reproduction of vocals and lead instruments, but with a bit of excess emphasis on the mid-range.
The Sennheiser HD 650 have a very good treble performance. Low-treble and mid-treble are flat and consistent, but with a 5dB tilt favoring lower frequencies. This results in a treble that lacks a bit of brightness and brilliance, which will be mostly noticeable on vocals, lead instruments, and cymbals.
The frequency response has above-average consistency. Due to their open-back and ear pad design, these headphones has near perfect consistency in delivering its bass. The maximum amount of deviation throughout the bass range was less than 1dB. However, they are prone to inconsistencies in the treble range, and depending on the positioning and ear shape, there could be as much as 6dB of variation in the treble response.
The imaging performance is great. Weighted group delay is at 0.15, which is excellent. The GD graph also shows that the entire group delay response is below the audibility threshold. This ensure a tight bass and a transparent treble reproduction. Additionally, the L/R drivers of our test unit were very well-matched. This is important for the accurate localization and placement of objects (voices, instruments, video game effects) in the stereo image.
The Sennheiser HD 650 have a below-average soundstage. The PRTF graph shows that these headphones don't interact with the pinna that much, and therefore show very little activation. They don't show a dip notch around the 10KHz area either. This means that although these are open-back headphones and may feel more open and spacious sounding that closed-back headphones, their soundstage won't be perceived to be large or located outside of the listener's head.
The harmonic distortion performance of the HD 650 is very good. The overall amount of harmonic distortion in the mid and treble ranges are very low, regardless of the volume. However, THD in the bass range is slightly elevated and is affected by an increase in volume.
The open-back design of the Sennheiser HD 650 encourages leakage to improve sound quality. However, this means they leak a lot and will disturb the people around you even at moderate volumes. They also won't block any ambient noise from seeping into your audio and won't fare well in loud environments or on a noisy commute, since they're not designed to be used outdoors.
The Sennheiser HD 650 have a poor isolation, due to their open-back design. In the bass range, where the rumble of airplane and bus engines sit, they achieve no isolation. In the mid-range, important for blocking out speech, they also achieve no isolation. IN the treble range, occupied by sharp S and Ts, they isolate by about 13dB, which is below-average.
The leakage is poor. The significant portion of their leakage is spread between 400Hz and 20KHz, which is a very broad range. This means the leakage will be fuller sounding compared to that of closed-back headphones and in-ears. The overall level of the leakage is quite loud too. With the music at 100dB SPL, the leakage averages at 60dB SPL and peaks at 74dB SPL, which is a lot louder than the noise floor of an average office.
The Sennheiser HD 650 have no microphone so the recording quality has not been tested.
The noise handling has not been tested since the HD650 have no microphone.
These headphones have no active features and therefore do not require a battery. They also do not have a dedicated app or software for added customization options.
These are passive headphones with no active components and no battery.
The Sennheiser HD 650 headphones do not have a dedicated, compatible app for added customization.
The Sennheiser HD 650 are straightforward wired critical listening headphones. Their cable does not have a mic for voice chat on console but will support audio when plugged into the PS4, Xbox One controller or PC. On the upside, since they're wired, they have practically no latency for watching movies and videos but do not have the convenient range of a wireless headphone.
These headphones are wired and do not have a Bluetooth connection. If you want a good Bluetooth headset for more casual use, check out the Bose QuietComfort 35 II.
These headphones come with 3 audio cables with no in-line remote. This means they will provide audio when connected to your PS4 or Xbox One controller but do not have a microphone for voice chat.
The Sennheiser HD650 do not have a dock. If you need a headset with a dock that also has a wired connection for gaming or watching movies, then consider the SteelSeries Arctis 7.
These headphones do not have a wireless range since they're wired. If you want a good wireless headset for critical listening, consider the Plantronics BackBeat Pro 2.
These headphones have practically no latency since they have a wired design. Unfortunately, this also means that they're limited by the range of the provided cables.
The Sennheiser HD 650 are great for critical listening but average headphones for everyday casual use. They deliver a good and open sound reproduction that caters well to all tracks. They're comfortable and don't feel tight on your head like the HD 600. Unfortunately, their soundstage isn't as spacious as other similarly designed open back critical listening headphones. Their build quality also isn't as durable as some of the competing models below.
The Sennheiser HD 650 are slightly better headphones than the HD 600 although not by much. The biggest difference between the two models is that the HD 650 are a bit more comfortable so you can wear them for longer than the HD600. They have pretty much the same sound quality although the HD 650 does have a slightly better bass and less treble, however, it's very hard to tell by listening alone. On the other hand the HD 600 offer a better value for your money for about the same sound quality.
The Hifiman Sundara are great-sounding headphones with a better design and build quality than the HD 650. They're an excellent choice for critical listening, thanks to their open design and planar magnetic drivers that help deliver a better bass than the Sennheiser and a more spacious soundstage. However, they can sound a bit sharp on already bright tracks. The Sundara are a better choice overall than the HD 650 for their build quality and more balanced sound. However, they're a bit more expensive.
The Sennheiser HD 598 are a more comfortable alternative to the HD650. They have a bit less bass than the HD650 so they won't sound as balanced, but their more comfortable fit means you can wear them for longer listening sessions. There is also a closed back variant of the 598 that delivers more bass and isolation for outdoor use but has a much smaller soundstage. If you like the signature sound of the Sennheiser HD series, then the HD 598 are a good slightly cheaper alternative to the HD650 with a similar sound but a more comfortable design.
The Bose QuietComfort 35 are good noise canceling headphones with a super comfortable design and a good enough sound for some critical listeners. They do not have the soundstage of the open back HD 650 but their closed back design delivers a bit more bass and provides enough isolation to make them practical for outdoor use. They're one of the more versatile over-ears we've tested although they won't as immersive as the HD650 for critical listening. If you have dedicated station/room for critical listening with an amp, and consider yourself an audiophile, then the HD 650 will be the better option. However, if you're looking for a good sounding headphone that you can also use outdoors while commuting or even running, then the Bose are a much more practical choice than the Sennheisers.