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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.
The 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.

sound descriptions mine

post separation
Sennheiser HD800S


The Sennheiser HD800S is an open over-ear dynamic headphone. It is marketed next to the HD800 and not a replacement. The price of the HD800S is a lot higher though.
Not only because of the color and the absorber that removes the 6kHz peak somewhat but also because of the extra (balanced) cable that comes with it.

Comfort of the HD800S is exactly the same as the HD800 which is very high.
Clamping force is very low and because the pads are very large and there is plenty of room in there for even the biggest ears you won’t get sweaty/hot ears.
There is a small chance, however, that depending on the shape/ size of the owners head seal may be broken resulting in less (sub)bass.

The connector is a LEMO-type 2-pin connector manufactured by ODU GmbH. This isn’t the cheapest connector around so when looking for a replacement cable be prepared to fork out quite a lot of cash.
Changing the cable is not a bad idea when you don’t like stiff, springy and long cables.


Type: Over ear, open
Isolation: poor
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 +  balanced 4-pin XLR cable.
Driver size: 56mm
Max. power rating: 0.5W
Max. cont. input voltage: 12V rms
Max. drawn current: 40mA
Max. S.P.L.: 125 dB
Impedance: 370 Ω
Efficiency: 98dB/1mW  (102dB/1V)
Weight: 330 g.
Clamping force: very low.
Accessories: 3m cable with 6.3 TRS connector, balanced cable with XLR4-connector, micro-fiber cleaning cloth, manual, USB flash drive


Sound description:

When I would have to give a very short description it would be this. A highly detailed and airy sound lacking ‘body/grunt’ and subbass.
To me the differences between the HD800 and HD800S aren’t that big. Yes it is somewhat less ‘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 ‘warmer’ but is because of the somewhat reduced 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’.


Below the frequency response of the HD800S (Left, Right)


Channel matching is excellent as should be expected in this price range.  Below 100Hz this headphone drops off very gradually. You can still hear deep rumbles but just not on an impressive level unless the recording has way too much lows in it.
Bass sounds ‘tight’ and very ‘dynamic’ and clean. Bass integrates seamlessly with the mids. Those mids are clear and articulate and have a decent presence.
From 100Hz to 1kHz the response is very flat and accurate.
The small dip from 1.5kHz to 5kHz may be a little less ‘deep’ in reality compared to the measurement  because the measurement rig does not have a pinna which does alter the response exactly in that area. That small dip is not audible.
The treble response is elevated. The 6kHz peak is still 5 dB too high (despite the absorber). The 10kHz peak even sticks out 10dB above the rest. This is perceived about twice as loud as it should be. No deep nulls or alarming amplitude variations. The amount of treble simply is too high.
This elevated treble is mostly responsible for the perceived high detail.
When this level is reduced by EQ one must be careful not to reduce the 10kHz part too much. That part is responsible for the fine detail reproduction and instrument ‘placement/localization’. When that level is reduced to the same level as the mids the headphone sounds ‘bland’ and lifeless.
This is why the Kameleon leaves part of this range somewhat elevated .

Below the differences between the HD800 and HD800S. (Right channel only)

HD800 vs HD800S
The similarities are very obvious. The differences too.
From 10Hz to 1kHz the differences are negligible. The effect of the absorber is quite obvious. A reduction of about 5 dB is achieved. But ringing is also reduced which cannot be seen on this plot.
The reduction achieved by the SDR mod from ‘Sorrodje’ from tellementnomade.org is about the same and can be fitted in the HD800 with some guts and while voiding of the warranty.
This turns the HD800 in an HD800S but with better ‘bass performance’ than the HD800S as the distortion of the HD800 is lower than that of the HD800S.


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 considerably 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 easier to see how the tonal balance changes.
120 Ohm

As can be seen the tonal balance changes just slightly when connected to a higher output resistance amplifier. You get about 1dB more lows. This can make the headphone sound slightly ‘fuller’. Lower bass is not boosted.

Below the distortion plot of the HD800S : (only Right channel shown)
Note that this headphone was measured at ears-unlimited-logo where  background noises were present in the demo room. As this is an open headphone distortion levels and spectrum plot performance may thus be better in reality than as shown on the plots.

The distortion products are shown in dB.HD800S R dist

Below the same data but shown in a percentage scale instead of a dB scale.

Dist HD800S R percent

The distortion profile is typical for a dynamic driver. Higher 2nd harmonic distortion in the bass. Don’t mind the peaks at 50Hz and 100Hz, they aren’t there in reality but are caused by the mobile measurement rig picking up some hum.
The distortion around 60Hz is around 1%
The measurement rig has a relatively high 2nd harmonic distortion so numbers below 0.2% above 200Hz will be there in reality. Distortion from 200Hz to 10kHz is very low.

Below the distortion plot of the HD800 (but measured under better conditions).
Dist HD800 R percent

When comparing the two headphones it shows that the HD800S has higher distortion levels below 100Hz. Particularly the 2nd order distortion.
This differences could be responsible for the perceived increase in ‘warmth’ in the bass of the HD800S as the frequency response clearly shows no differences in amount of lows.

Below the CSD of the HD800S (Left and Right channel are superimposed)

The CSD shows a quite good response with no obvious and deal-breaking resonances or lingering. Small and short lived resonances can be seen at 6kHz and 10kHz though but doubt these are detrimental to the treble quality.

Below the HD800 CSD plots as a comparison.CSD HD800

As can be seen the absorber in the HD800S does a good job. Not only the amplitude of the 6kHz resonance is lower in the HD800S but the ringing is also much better damped/shorter lived. For the higher frequencies the absorber does not do anything.
The used ‘Helmholtz resonator’ seems to be perfectly tuned to the biggest ‘flaw’ of the HD800.

By lack of oscilloscope shots (not enough time to measure that) below a step response plot of the HD800S (Right channel)Step HD800S R

The fast impulse response of the HD800S is clearly seen as it reaches the 0dB line.
It is not really overshoot but the 6dB dip following the initial rise is a bit high.
What can be observed as well is that there is some ringing visible in a high frequency (10kHz). The gradual downwards slope is evidence of the slight slope in the bass/sub-bass.

Below the HD800 for comparative reasons.

Step HD800 R
What is obvious here is that the dip after the initial rise is deeper and that the resonance after it is lower in frequency (6kHz) and takes about twice as long long to die out.

below the step response of the HD660S.
step HD660S R

The step response clearly shows the lack of ‘bottom end’ as evidenced by the downwards sloping line. Headphones with a good sub-bass extension have a (close to) horizontal line after the initial rise. What can be seen is the superior initial rising flank which stops at 2dB below the 0dB line. On the other hand there is as good as no ringing seen at all.



This headphone is top notch when it concerns fit, finish, looks and craftsmanship.
Tonal balance is bright and ‘thin’, overly detailed.
Instrument separation as well as dynamics and retrieval of the finer nuances is among the best of the TOTL headphones out there.

The elevated treble and slightly rolled off subbass are still downsides. The treble quality is better than that of the HD800 but the bass quality is not as good as the HD800.

Is it worth upgrading from the HD800 ?
When you like the tonal balance of the HD800 and are only looking for somewhat less ‘sharp’ treble and don’t mind the bass quality to be very slightly different then the HD800S may be an ‘upgrade’. When you are not afraid of some DIY and don’t need the balanced cable nor the black accents then the SDR mod is a better and cheaper idea.
A little bit less ‘romantic’ presentation perhaps then it might be worth ‘upgrading’.

When the lack of bass and elevated treble is something that you don’t particularly like but do like the other great assets of this headphone than the Kameleon or (software) EQ may be a way out.

Technically an excellent (maybe close to the being the best) headphone but to me a bit too bright and too ‘lean’. Fortunately there are fixes for this that do not affect the other excellent qualities.

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