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Isolation |
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• Decent max volume for a set
of open-backed headphones.
• Poor isolation.
• Leak a lot of sound. |
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Sound Quality |
Page 4 of 12 |
Comfort |
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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.
Isolation
(1.26)
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.
Leakage
(2.90)
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.
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