Pros
Cons
Tour & Design
Tour**
Welcome to the Sennheiser HD 650s. Below are the left, middle,
and right of the headphones.
The HD 650s are open-backed headphones, which is obvious if you
look at the outside of the ear cups. You can see the headphones'
innards clearly through the external grating.
The underside of the cups is where the cord attaches.
The underside of the band has padding with a divot at the top to
allow the band to bend without scrunching up the pads.
The headphones come with a Y-style cable that's over 9 feet long.
Here's a close-up of the plugs that affix
the cable to the ear cups.
As always, we conclude our tour by taking candid photos of HATS, our
head-and-torso-simulating robot pal, wearing the headphones it's helped
us test. Use this picture to get a very, very, very vague impression of
what the headphones will look like on your own head. We've gone ahead
and assumed you won't always remember to make the band symmetrically
extended, leading to a slight off-kilter look.
In The Box
In the box you'll find a storage case and an 1/8-inch adapter.
The HD 650s seem to be a pretty durable set of headphones overall,
with very specific strengths and weaknesses. On the plus side, the cord
is thick (a plus on at-home headphones, but makes them less portable)
and also removeable. If the cord gets damaged, just swap it out for a
new one.
On the negative end, the HD 650s have an open-backed design. While
open backs do some nice things for sound quality, it lets dust get into
the guts of the headphone very easily. Further, the grating isn't
particularly sturdy, and will probably dent if it fell off your desk.
Unless your desk is several hundred feet above ground, the dent will
likely just be an aesthetic issue.
These negative features are very minor in relation to the overall
construction of the headphones, however. While some dust can flow
through the grates, there's a felt guard to protect the important bits.
In general, the HD 650s are a sturdy set of headphones.
We like the looks of the Sennheiser HD 650s, but their unique look
certainly won't be for everyone. The large oval grating on the outside
of the ear cups is functional, of course, but also creates an
interesting look. The headphones are over-ears, which might look a bit
large on your head if you're not used to them. The greyscale paint job
doesn't create much of an aesthetic draw. While this might make them a
bit boring to some, it also makes them work-appropriate (if you are
planning on using these at work, we have to warn you: they leak like
crazy, so you'll have to keep your volume down if you don't want to be
the office boom box).
Sound Quality
**
About our testing:**
For more information on our tests, read this
article.
**Frequency
Response** (*4.42**)*
What we found:
The HD 650s had an average frequency response. As you can see, the
headphones have an average response in the bass end, but gradually fall
off towards the high-end. The response becomes slightly erratic as
well, leading it to dip slightly below the bottom limit a few times by
varying amounts.
While the HD 650s didn't have a perfect response, they still did pretty
well. They never went drastically far outside our set limits and there
weren't any sharp volume changes across small frequency bands.
How the Sennheiser HD 650 compares:
What is frequency response?
The term 'frequency response' describes the amount of emphasis the
headphones put on each frequency. Some headphones try not to alter
anything (reference headphones), but some choose to emphasis certain
frequency ranges, such as boosting bass (dynamic headphones).
How the test works:
For this magical test, step one is putting the headphones on HATS. Once
step one is completed, we play a frequency sweep through the headphones
(step 2). HATS listens to the playback (step 3) then reports back to
SoundCheck (step 4). SoundCheck compares HATS's data to the original
sound (step 5), then spits out a graph that depicts what the headphones
are doing to the playback. We then write up a review (step 6) and post
it on the internet (step 7). If you want to learn more click this
link (step 8 [optional]).
What we found:
The less distortion a set of headphones has, the less we can say about
it. The HD 650s didn't have a noticeable amount of distortion at any
point throughout the frequency gamut we tested. Audiophiles should be
quite happy with these headphones.
How the Sennheiser HD 650 compares:
**What is distortion?
**Bad, for starters, but only if you listen to certain kinds
of music. Distortion refers to any garbage the headphones add to your
music. This could be noise, or simply changing the shape of the
incoming soundwaves. If you listen to acoustic music, you'll notice
distortion much more easily than if you listen to rock or punk.
How the test works:
Our distortion test plays a series of frequencies through the
headphones, allowing us to compare the original to the recorded sound,
thus figuring out what the headphones are doing. If you want to read a
longer explanation, this
link will make all your wildest dreams come true.
What we found:
The HD 650s had good tracking overall. This means there wasn't any
frequency at which the left ear cup was playing noticeably louder than
the right, and vice versa.
How the Sennheiser HD 650 compares:
**What is tracking?
**Tracking describes the relative volume output of the left
and right channels (in this case, the left and right ear cups). If a
sound is set to play through both ear cups at the same decibel level,
both ear cups should be outputting the same decibel level as well. If
the left channel consistently plays bass louder, or if the right
channel tends to screech high-end frequencies at you, then your
headphones have bad tracking.
How the test works:
This test is an easy one. We just play a frequency sweep through the
headphones and have HATS listen. Each frequency is set to play back
through each channel at the same volume. We note the spots at which one
channel is louder, and that gives us the above graph. When the line
drifts above the X-axis, the right channel is louder. When the line
dips below the X-axis, the left channel is louder. For more info, you
can click here.
Isolation
**Maximum
Usable Volume** (6.51)
What we found:
The HD 650s were capable of outputting 105.33dB without accruing
significant distortion. Given that these headphones have open backs,
this is actually pretty impressive and should allow you to annoy
everyone in the vicinity with your music.
We award maximum points for 120dB, which is the loudest you'd want
your playback unless you're determined to deafen yourself. Since the HD
650s are open-backed headphones meant to be used in a private listening
environment, 105dB should be plenty loud.
**What is maximum usable volume?
**Most headphones are capable of a very high volume output,
but sometines that output sounds like garbage. This is because an
increase in volume can often increase distortion. The level of
distortion we look for is 3%, which is when your music will start
sounding ugly.
How the test works:
This test is a series of our distortion tests run at various decibel
levels. We keep bumping up the volume until we hit 3% distortion or
120dB (for which we award maximum points: 10). The reason we don't keep
awarding points past 120dB is because we love you and don't want you to
hurt your precious little ears. If you would like to read more about
this or our other tests: link.
What we found:
We have found, through scientifically rigorous testing, that
open-backed headphones don't isolate well. This may be shocking news to
some, but we assure you it's correct.
Since the HD 650s don't have any physical barrier blocking out external
noise, and they don't have any active cancellation wizardry going on,
they have very poor isolation.
How the Sennheiser HD 650 compares:
**What is isolation?
**Isolation is what stops all the noise of this world we
live in from interrupting your music. Headphones with great isolation
will totally block out ambient noise, while headphones with poor
isolation will allow the car horns and jackhammering to sing along with
your music. There are two types of isolation: passive isolation and
active cancellation. Active cancellation uses a microphone in the
headphones to listen to surrounding noise, then plays back its inverse.
The noise crashes into its inverse, and both cease to be. The downside
is this process requires batteries and isn't perfect: it often creates
as much noise as it blocks out, or adds distortion to your music.
Passive isolation is the brute force approach, and blocks out noise by
simple virtue of a solidity. Stick any solid object into or onto your
ears and you've achieved passive isolation. Some soundwaves will not
make it through the barrier at an audible level.
How the test works:
For our isolation test, we play a bunch of noise at HATS, who is
wearing the test headphones. HATS records the levels of noise it can
hear, which lets us know exactly what's being blocked out. If you would
like to know more about this test, feel free to peruse this
article.
What we found:
Again, since these are open-backed headphones, there isn't much of a
barrier between your soundstage and the world around you. The HD 650s
leak like crazy, thusly fulfilling the purpose of their design.
What is leakage?
In the world of headphones, leakage describes the degree to which your
playback will be audible to those around you. If a set of headphones
has open backs, playback will seem about as loud to those around you as
it does to you. While this is a not-so-subtle way to impress those
around you with your impeccible taste in music, it's also inappropriate
at most times. If you're in the office, for example, you probably don't
want headphones with high leakage.
How the test works:
To test leakage, we put the headphones on HATS and play some noise back
through them. There's a microphone set up a small distance away that
records any and all noise that's audible. From there we toss that data
into a very complicated formula and (huzzah!) we have our score.
Comfort
The Sennheiser HD 650s might not have the softest velour or
sheepskin padding, but the headphones themselves are pretty comfortable
to wear. The headphones are very light and don't put a lot of pressure
on the head, either on the top or on the sides. After an hour we had no
real complaints.
We really didn't have any complaints after a marathon listening
session of 6 hours. They didn't really become less comfortable over
time, although the padding grew to be slightly itchy at times. Overall,
the HD 650s provided a comfortable wear experience.
Of course, this score and the one above are entirely subjective. Try on
the headphones yourselves for at least a few hours before you make a
final decision about keeping them. As anyone who's worn an
uncomfortable set of headphones can assure you, this is very, very
important.
There really isn't a lot of customization available for the HD 650s.
You can tilt and swivel the ear cups slightly and the band can extend.
There aren't any additional add-ons or optional accessories included in
the box.
Usability
**Cable
Connectivity** (12.22*)*
The HD 650s cable is 9 feet, 9 inches, which is a great length
for a set of at-home headphones. This is long enough to stretch to an
audio set-up that's across the room from your favorite easy chair.
The HD 650s have a 1/4-inch plug but come with an 1/8-inch adaptor.
These aren't portable headphones in any sense. First of all, they're
large; if they're not no your head, you'll need a separate bag or
container to carry them since there's no way they'd fit in your pocket.
Also, the thick, long cord is simply unwieldy, taking up a significant
amount of pocket space.
The headphones do come with a case, but it doesn't help you port
them around much. There's no latch to it, so it's really better used as
a storage device.
There's not an awful lot you can do for headphone maintenance.
You can take off the padding, but that doesn't really get you to
anything worth repairing. You can't remove the grating, so if the back
of the headphones get dusty you'll have to rely on compressed air. The
one positive maintenance feature is the removeable cord. If the cord
should succumb to wear and tear in some way, you can cheaply replace it
with a new one.
Battery Dependency
The HD 650s don't require batteries, so they get some points here. This
is because batteries are annoying. They require you to maintain an
additional power source, either by recharging or replacing the
batteries. If your iPod still has juice, you should be able to listen
to music with them.
Sennheiser HD 555 Comparison
The HD 650s have better aesthetics and durability. The HD 555s are
very plasticky and don't inspire a lot of confidence in their
ruggedness. The HD 650s have a much more solid construction.
**
HEY, READ THIS: **We have to start this section with a caveat. See,
the HD 555 was one of the first headphones we ever tested (oh,
nostalgia), so the graph extends all the way down to 20Hz. We stopped
showing that part of the graph because our testing rig isn't 100%
accurate for that range. Just disregard the bit below 100Hz and you'll
be fine.
The HD 650s gain a tiny advantage on frequency
response. The HD 555 had a slightly more erratic high end. The
differences between the two are minor.
The HD 555s' graph is a bit misleading because,
like the graph above, it includes data from the 20-100Hz range.
Disregarding that chunk, you can see that the HD 555s still have
slightly more low-end distortion than the HD 650s, but slightly less
distortion overall. Basically, neither set of headphones has much
distortion.
The HD 650 gets a solid advantage here with an
even tracking. The HD 555 has some issues with the high end.
Neither set of headphones is a good choice if you're looking for
isolation.
Both sets of headphones have very similar fit and padding type.
They're about the same in terms of comfort.
Verdict
While the HD 650s are a better set of headphones, they aren't better
by all that much. Most of their advantages come in the form of
subjective qualities, like clarity and a larger, more open soundstage.
In terms of our testing, however, they're really similar. We recommend
trying them on back-to-back and seeing if the HD 650s manage to strike
you as worth the extra few hundred dollars.
Audio Technica ATH ESW9 Comparison
The ATH-ESW9s are a high-class set of headphones. They have wooden
backs and lambskin padding. They look quite rich.
The ATH-ESW9s also feature a slightly more sturdy construction, mainly
due to their closed backs.
The ATH-ESW9s have some issues with their high
end. After 1kHz, the ATH-ESW9's response starts dropping and falls
below our bottom limit, then becomes erratic.
In terms of distortion, both headphones are equally amazing.
The HD 650s have better overall tracking, remaining much flatter up
until the high end and remains less erratic as it approaches the 10kHz
mark.
The ATH-ESW9 can isolate much better than the HD 650, but we
wouldn't say either have particularly good isolation.
The HD 650s are more comfortable overall. We thought the ATH-ESW9s
were too tight and got slightly worse over time. The ATH-ESW9s had far
more comfortable padding, however, so be sure to try on both sets of
headphones: if you don't run into the fit issues we did, the ATH-ESW9s
would easily be more comfortable.
Both the HD 650s and ATH-ESW9s have different strengths and
weaknesses. The ATH-ESW9s don't have the same calibur audio quality
that the HD 650s do, but they look significantly nicer. If you're not
much of an audiophile and you want a good sound and better looks, the
ATH-ESW9s are a good option.
Beyerdynamic DT 990 Comparison
We think the DT 990s are sharp-looking headphones. The splash of
color doesn't make them a goofy set of DJ headphones that aren't
appropriate, it just makes them delightful. They're also a more
traditional design as opposed to the beehive-like grate on the HD 650s.
The DT 990s are also slightly more durable, sacrificing a true open
back for a less permeable design. They also implement metal in leiu of
plastic.
One additional aspect to keep in mind is Beyerdynamic's MANUFAKTUR
feature, where you can order a pair of DT 990s online and choose your
own color combination.
The DT 990s did a better job staying within our
frequency response limits, but they have a significant decibel hike
around the 7kHz mark.
There's virtually no distortion on either side,
although the HD 650 features slightly less.
The HD 650s have better tracking. Like most
headphones, the DT 990s have a slight blip towards their high-end.
Neither set of headphones are good isolators. The DT 990s do a
slightly better job, but it's nothing to brag about.
While both headphones are comfortable initially, the DT 990s got
increasingly uncomfortable over time. The band pressed hard against the
top of our testers' heads after a few hours, requiring them to shift
the band to continue use.
The DT 990s feature a slightly better set of test results and an
uncomfortable fit. This comparison is so close that it's really up to
the user to decide which one is better. Be sure to wear them for a few
hours to check for any fit issues. If you find the DT 990s are
comfortable, they slightly superior sound and lower price point will
probably be the better bet.
Grado SR60 Comparison
The DT 990s say, 'I am a pair of high-end headphones, but not stuck
up about it.' The Grado SR60s say, 'Haha, hey guys, remember the '80s?
I'm so ironically attractive it laps regular irony and puts me into
double, if not triple irony.'
Aesthetics aside, the DT 990s are far, far more durable, featuring much
more metal than plastic.
The Grado SR60s have a slightly better frequency response, although
it does feature a pronounced dip towards its high end.
The Grado SR60s don't have the best distortion result, showing some
low-end and high-end spikes. The HD 650s features smooth sailing along
the zero line.
The HD 650s have a smoother tracking result, which was again achieved
simply by not screwing up the high-end.
While the HD 650s are better isolators, neither set of headphones
should be your first choice in this category.
The Grado SR60s have bad padding. Not only do they dilute the audio
quality by creating a terrible seal with their user's ears, but they
also get hot and scratchy. The headphones themselves, however, fit
well.
We thought the HD 650s we a better wear experience overall.
The SR60s aren't a bad set of headphones for their price. If you
like their looks and can get some replacement padding, then they're a
good pick-up. The DT 990s, however, are stellar right out of the box,
and they're certainly more un-ironically attractive.
Conclusion
Meet the tester
Mark Brezinski works on the Home Team, reviewing refrigerators, minifridges, dishwashers, washing machines, dryers, air conditioners, air purifiers, and fans.
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