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Published: Nov-18-2015, updated: Apr-3-21

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NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons flat’ sharp peaks and ‘wiggles’. I do not use smoothing because some info about sound quality is lost when plots are smoothed.

Aside from a small correction of the microphone itself also some correction in the lowest frequencies is applied to the plots to compensate for the perceived loss of bass when using headphones. This is described HERE in more detail.
A ‘horizontal‘ frequency response curve on the shown frequency response plots on this website thus indicates a perceived ‘flat’ tonal signature.

ALL measurements are made with a good SEAL on a flatbed measurement rig.
shape of your head, bone structure, pad size, pad ‘softness,  (compliance), hair or no hair and or wearing glasses may (drastically) change the frequency response of some headphones, so… your personal experience may differ substantially from these plots.

Frequency response (tonal balance) is the most sound-determining aspect of headphones. A horizontal line shows audible neutral response in the plots on this website. Deviations in different severities at different frequency bands have an effect on the sound character.
The bigger the deviation the stronger the effect.

Below an aid to help determining the sound character of headphones with relation to the frequency response.


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Sennheiser HD800

HD800 kl

The Sennheiser HD800 is not showing up anymore on the Sennheiser website as of Jan 2019.
Given the price range of  ‘flagships’ like Audeze LCD-4, Focal Utopia, HiFiman HE1000, Abyss AB1266, Sennheiser Orpheus HE-1060, Stax SR009 system the standard price isn’t even considered absurd anymore.
I got this one second hand for a reasonable price. 2nd hand prices will drop though with the new HD800S coming out. That one has more (percived) bass and somewhat less 6kHz treble peak.
This headphone is very comfortable. The cups and headband can be adjusted over a wide range. There is more than enough room for any ears in existence.
The clamping force is very low so not suited for walking around with it. Nor can it be driven well from phones, laptops and tablets. It really needs an amp that has a high enough output voltage.
The cable is long and stiff but not very microphonic. There are plenty of (expensive) aftermarket cables if you want a different length, supple-ness, colour or material.
They will always be expensive because of the used connectors.
This is a controversial headphone that is either liked or hated.


Type: Over ear, open
Isolation: poor (open headphone)
Usage: Home
Driver type: dynamic, ring driver
Pads: replaceable microfiber
Foldable: No
Headphone cup connector: proprietary ODU GmbH 2 pin connectors.
Cable entry: dual sided
Cable: 3m 6.3mm TRS
Driver size: 56mm, angled 10º
Max. power rating: 0.5W
Max. cont. input voltage: 12V rms
Max. drawn current: 40mA
Max. S.P.L.: 128 dB
Impedance: 370 Ω
Efficiency: 101dB @ 1mW
Sensitivity: 105dB @ 1V
Weight: 380 g. without the cable, cable = 130 g.
Clamping force: very low.
Accessories: 3m cable with 6.3 TRS connector, instruction manual, wooden storage box.

sound description

The short description it would be this. A highly detailed and airy sound lacking ‘body/grunt’ and subbass. It can be ‘sharp’ sounding with most popular recordings.
With most classical recordings it sounds good right out of the box and without any EQ.
To me the differences between the HD800 and HD800S aren’t that big. The HD800 is somewhat more ‘grating’ in the treble but that is really the only audible difference to me.
Most people claim it has more bass but to me it is the same. It does sound a bit less ‘warm’ because of the somewhat elevated treble around 7kHz which ‘overpowers’ the sound in the HD800 way too much.
This is better in the HD800S but this one still is ‘overly’ trebly/bright and ‘hyper-detailed’ because of the ‘treble plateau’
Imaging and stereo separation is top notch. With this I mean placement of instruments in the sound field and the ability to perceive them ‘separate’ and ‘realistic’ is excellent.
This is the strong point of this headphone, along with wearing comfort.
For music, other than classical, the HD800(S) needs some EQ in the treble and the lower bass. Even with the treble reduced the detail retrieval and ‘airy’ sound remains… just not overly hyped but just more realistic and less fatiguing.


Below the frequency response on a more flattering scale as previous measurements. Also note that the frequency response of the measurements spans 10Hz to 30kHz.
I think everything down to 10Hz is fairly accurate but above 10kHz is the no guarantee zone. The microphone used seems to top out at around 27kHz but don’t know how accurate absolute levels are. As the measurement setup is cheap … don’t bet on absolute accuracy. Ignore the ‘wiggles’ around 50-60Hz, they aren’t really there. A measurement error. This is true for all measurements on this website though. Left, Right

HD800 FR 30k

This is quite representatitive of how it sounds. Bass-shy though deep bass notes can still be heard but not as loud as it should. Quite accurate mids and BRIGHT.
Quite good channel matching.
Way too bright and because of it highly (overly) detailed and ‘spacious’ and ‘fast’ sounding. The large membrane, however, does not seem to do much above 20kHz though, compared to the HD650.
Below a comparison of the HD800 and HD650 (black driver but fitted with new pads)

HD800 vs HD600 new pads

The differences are obvious. The HD650 is warmer, has a bit more ‘presence’ in the area between 1kHz or 3kHz) or should I say the HD800 is lacking in that area.
The sharp rise and the peaks in the treble area make the HD800 sound so ‘thin’, ‘bright’ and ‘highly detailed’. Flat and ‘accurate’ the HD800 is absolutely NOT.
Notice how the HD650 is much flatter and accurate and has similar subbass and even better treble extension. Of course if most of the music you have is CD then everything above 20kHz is really moot.

Below the distortion plots of the HD800, left channel only, the right channel measures the same.DIST HD800L

The frequency range differs from the FR plots, these ones run from 30Hz to 30kHz. The distortion of these headphones, especially in the bass area is impressively low.
As a comparison below the distortion plot of the HD650 which has more distortion.
Around 40Hz there is a 40dB ‘distance’ between the signal and the 2nd and 3rd harmonics.
The HD800 does quite a bit better and shows a 46dB distance. At 1kHz the HD800 has a ‘distance’ of 58dB where the HD650 (no slouch in the distortion department either) has a distance of 53dB. So the HD800 does perform better in the distortion department.
Below the distortion plot for the HD650

DIST new pads

Then there is also the waterfall plot or C.S.D. which is shown below and gives us some clues about ringing of the driver.

At 6kHz and 10.5kHz resonances are visible. It’s not ringing very long though. Left and Right superimposed

output resistance / damping-factor

As this is a dynamic headphone the frequency response might be amplifier output resistance dependent when certain higher output resistance amplifiers are used.
To test this the headphone is measured via a low impedance amplifier (0.2Ω) and a high impedance amplifier (120Ω). On a higher output resistance amplifier the output level will be 2.1dB lower. To compensate for this the amplifier is cranked up to the same level (at 1kHz) as the low impedance amplifier. This way the plots are overlay-ed and it is easy to see how the tonal balance changes. 120R -2.1dB
This headphone does react slightly to a higher output resistance by increasing the lower frequencies by about 1dB.
There is very little change when using this headphone from a higher output resistance amplifier.
Below the CSD of the HD800 via 0.2Ω and 120Ω120 Ohm CSDHere too it is obvious the higher output resistance doesn’t change much in the middle to high frequencies, only the level differs (due to voltage division).


Seal can be an issue with closed-back headphones but is usually less of a problem for open headphones. Breaking the seal (improper fit on the head) usually means a loss of (sub)bass. Below the effect of different levels of seal breach are shown.
Perfect seal, Seal broken with a thin arm pair of glasses, seal broken using thick armed glasses.sealThere is some reaction to seal loss below 100Hz so a good seal is of some importance to get the best bass extension.

Below a comparison between the HD650 and HD800. As can be seen the HD650 is not as ‘clean’ in the lower part of the FR (500Hz in this plot).
The HD800 is not ‘better’ though. The green part around 2kHz is higher in amplitude only so it seems as the HD800 is ‘better’ there. Likewise it would appear as though the HD650 is ‘better’ above 4kHz but again… this is only an ‘amplitude’ based difference. Both headphones do well in the CSD department.

CSD HD800 vs HD650

Below the spectrum plot of the HD800 (Right channel) the signal drops  down to -35dB fast all over the spectrum but takes a bit longer after that. No obvious problematic behaviour is shown here.spectr HD800 L

A way of looking at an impulse can also be done with a step signal. The plot below shows that after the initial step there is quite some ringing visible (8dB !) after the initial flank.
The sloping horizontal line indicates the subbass response is not that great and some LF roll-off is there.

Step HD800 R

Other interesting measurements are squarewave responses and needle pulses. These tell us something about the speed of membrane as well as how much they continue to vibrate after they are supposed to stop moving.
There are no software analysis in these squarewave plots and no sound cards involved either. Just a real squarewave and an oscilloscope so no digital filter ringing artefacts etc.

3 different measurements are made… They are explained HERE if you want mor info.
As above many comparisons are made to the HD650 below the plots will be no different.
On the left the HD800 with a 40Hz squarwave                          on the right the HD650.

40Hz SQR HD800

new pads 40Hz



Below the plots of a 440Hz squarewave.
On the left the HD800                          on the right the HD650.

440Hz HD800

new pads 440







The HD800 (on the left) isn’t really looking like the original applied squarewave. The HD650 (on the right) is much closer to the stimulus.

Below a 100μs needle pulse (choice over the usual 50μs is explained HERE).
On the left the HD800                     on the right the HD650

10us pulse HD800

new pads 100us








Here the differences between the HD800 (on the left) and HD650 (on the right) clearly start to show.
After an impulse the HD800’s bigger membane overshoots (the treble peaks) and has difficulties with stopping to vibrate.
The frequency it rings at is 5.85kHz (not surprisingly).
The HD650 is MUCH better damped and thus may sound a bit more ‘boring’ in the treble but actually is a much more accurate driver.

If you are on a budget and are still continuously haunted by the idea you need to upgrade from the HD600 or HD650 to an HD800 then above there may be some answers to your questions. To me, without doubt, the HD650 is technically the better headphone but if you prefer less ‘warmth’ and like a more ‘fierce’ treble the HD800 (when bought second hand) may be a nice break from the HD650. Personally I would recommend the ETHER over the HD800 given that they are in a similar price range when bought new.
Not a headphone for bass-heads for sure.

cloth inlay effect

Below measurements of the HD800 with and without the cloth ‘inlay‘.HD800 cloth effect

cheap Chinese replacement pads

I bought some cheap Chinese HD800 pads from e-bay (€ 10 .- ) that were similar looking. There are also quite different looking HD800(S) pads available which in most cases change the sound signature. Below using (a bit worn) original pads where the foam has started to fall apart vs the similar looking and feeling Chinese replacement pads.chinese lookalike pads
The lesson we can learn here is that these are measurable and also audible different from the original pads. In a broad sense the tonality didn’t change much but there are slight differences in clarity of voices and instruments. Not very big but noticeable.
Left to right: Leather pads, cheap imitation HD800 pads, original pads.
Curious about the leather pads I found on e-bay I ordered some sheepskin leather pads of around € 30,-.
Turns out the part that touches the skin appears like real and soft leather but the sides of the pad are made of pleather. I hope these won’t flake and turn ugly after a while.
They are rather difficult to fit on the HD800 and even harder to take off again. original pads, imitation HD800 pads, leather pads.
What’s obvious is the 6kHz peak seems to be gone. Overall treble is still elevated and even more so around 7kHz so brightness doesn’t change.
Also below 40Hz the drop-off is a bit worse. Audible it does not sound very different from the original pads so are a viable alternative for the original pads. No idea how long the fake leather sides will last.
The silicone ‘seal’ is not present on the back of the leather pads which may well be responsible for the bass roll-off.

passive filter

The treble peak of the HD800 is lowered using a passive resonator in the HD800S.
One can retrofit a similar DIY filter into the HD800 but this requires some (not so difficult) ‘surgery’. The effect is similar to that of the HD800S.
To order this you can contact member ‘sorrodje’ at SBAF.
Another solution is to build (or buy) a passive filter that sits between the headphone amp and headphone cable. The schematic is shown below.
The effect of this filter is shown below. Stock HD800, HD800S and HD800 with passive filter.HD800 vs 800S vs HD800 filter

Also ave been playing around with the Kameleon amplifier and am trying to make a filter that improves bass response and lowers the 4-8kHz area.
The goal is more ‘body’ and to remove the ‘overly bright’ treble while not removing the detailed character.

Below the results of some playing around and are thus preliminary results. The filter may still be changed.
Right channel only stock HD800, HD800 via Kameleon

Kam vs stock

I also ‘removed’ the peak between 10k and 20k but this completely removed the detailed character of the headphone. That elevated treble is there for a reason… the 6kHz peak seems a by-product that is unwanted and gives it the ‘sharp’ edge.
So the >10kHz peak must stay. In fact I made it extend a little further so it doesn’t roll-off till about 24kHz.

Distortion is about the same. The bass distortion appears higher but it isn’t. The distance in dB between the signal (red trace) and the distortion products remain the same.Likewise for the treble distortion, which appears to have improved, is actually the same. The signal level is lower and thus also the harmonics. The distance between stimulus and harmonics is the same… and that’s what counts.

Kam DIST R HD800

Then there is the CSD which obviously changed as well.
Right and Left channel are superimposed.

CSD Kam HD800

Below the step response difference.
On the left the stock HD800, on the right via the Kameleon.

Reduced ringing and improved subbass response is obvious.

Then there is the square-wave and needle pulse response.
On the left the stock HD800, on the right via Kameleon amplifier.

HD800 sqr

Remember, scope plots are linear scale measurements (both in time and amplitude)  where all the other measurements are logarithmic (both in amplitude and frequency).
The 40Hz squarewave is improved. The 440Hz signal shows less ringing but also less ‘speed’.
The 100μs pulse doesn’t overshoot (which is the 6kHz ringing) but lacks in overall amplitude.

When you compare it to the HD650 (on Kameleon) it shows that the HD650 is actually the better ‘performing’ headphone (technically).

To me the sound has improved so much that I can finally listen to it and enjoy it. Still highly detailed and with ‘body’ now.
After much time with it and enjoying the sound the headphone seemed to ‘induce’ tinnitus. This doesn’t happen to me with other headphones.

Suspecting this is caused by the peak >10kHz some experiments were made using damping materials in front of the driver like felt and toilet paper. To reduce the upper peak 1 ply of toilet paper seemed to do the trick combined with the Kameleon amp.

Below a frequency plot of the HD800 via the Kameleon and the same combo with 1 ply of toilet paper.TP effect on Kameleon HD800

As can be seen the toilet paper is effective at lowering the upper treble.
It also lowers the treble extension as an unwanted side effect.
Will experiment with some felt as well in the future.

As suspected the ‘hyper details’ of the HD800 are ‘located’ in the upper treble. With the toilet paper I haven’t been able to envoke tinnitus so it does help with that BUT also reduces the detailed sound to ‘normal’ levels and somewhat narrows the overly wide stereo image.
It is much easier to listen to music with this small roll-off while retaining some of the finer qualities of this headphone.

Below the L and R frequency response of the HD800 on Kameleon and with 1ply of toilet paper between the driver and the dustcover.

Kameleon + TP FR

Looks nice accurate. Sounds accurate as well but less ‘splashy’… polite yet very open and dynamic.

Below the difference between stock and via Kameleon with toilet paper.

Kameleon + TP vs stock HD800

For completeness also the CSD of the stock and Kameleon + toilet paper

CSD Kameleon + TP vs stock

The squarewave and needle pulse response differs substantially between stock (left) and via Kameleon + toilet paper (right)

HD800 on Kameleon + toilet paper


The HD800 is an excellent headphone on a number of fronts. One of them is hard to show in graphs, and that is the excellent stereo imaging. The drivers being far away from the ears under an angle and being large as well as having the ring-emitter properties are most likely the reason for this.
Aside from the 2 peaks around 6kHz and 10.5kHz the frequency response is very smooth with no sharp dips.
Bass is a bit low in level but still extended and sounds good.
With some EQ this headphone is exceptional and still one of the best headphones around.
The comfort is high but the large cups may not be fitting on all heads that well.
The foam in the ear pads and headband falls apart pretty soon and looses firmness.
For those who like to use other cables (the original is horrible) there are many options but all of them quite expensive due to the used connectors.

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