Fidelio X2HR

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published: Nov-14-2019, updated: Dec-25-2019

post separation

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.


post separation
Philips Fidelio X2HR


The Philips Fidelio X2HR/00 is an open headphone launched in 2017 and successor of the X2 (2015) which in turn was the replacement of the Fidelio X1 (2013).
This headphone feels and looks luxurious and well made. When one thinks of headphones one of the last things one thinks of is Philips but this is not deserved.
The MSRP is around €350.- but around end 2019 one can find these at prices between €160.- and €240.- I got the 3rd one on Black Friday for €119.-

The headband is self-adjusting. This is done by metal springs so should last a long time. The part that touches the head is made of cloth and quite wide so pressure is distributed over a larger area. No creaking parts and the design looks sturdy and well engineered with metal parts. Nothing screams cheap.

The pads are replaceable and velours. They are soft and comfortable and distribute the somewhat highish clamping force quite evenly. The memory foam pads feel firm and provide a good seal. I don’t think it will be easy to find after-market pads as the mounting ring is quite specific. I have no idea how long these pads will last and if replacements will (still) be available after many years.

The clamping force is higher than average.  After a few hours taking the headphone of is a relief and I developed some headache due to the clamping force.
If it were mine I would try to lower the clamping force by carefully bending the rods.

The cups can swivel and tilt far enough and the height can be adjusted over a wide range as well. This headphone thus will fit a lot if not all head-sizes.

The cable that came with this headphone is 3 meter. Quite suited for usage with desktop/home equipment but less so for portable gear. The fact that the headphone is open means it really is not suited for outdoor usage. Using it indoor directly from a phone or DAP is quite possible. The solution Philips offers is a clamp that can be used to ‘shorten’ the cable. Not really a useful thing. Instead I would recommend buying a shorter cable for portable usage. As a standard (non locking, non proprietary) 3.5mm TRS jack is used it will be very easy to find another cable.
Aside from the length for portable usage there is a downside to the supplied cable.
It is relatively stiff and cloth covered. Yes it looks nice but is microphonic and a bit too heavy. I would replace it with a suitable length supple cable. This will lower the microphony.

No possibility to use this headphone with any balanced amplifier as the socket in the X2HR only has 3 pins (3.5mm TRS plug).

With its 380 g (440 g with cable) it is not exactly a lightweight headphone but it still is light enough for longer listening sessions (when the clamping force is lowered).

The overall looks and quality feel is excellent (personal opinion on the looks). The efficiency is high enough and the impedance (30 Ω) is friendly for most music sources. This headphone will play quite well and loud enough from most phones. It has a high power rating (0.5W) so you won’t blow it up when connected to a decent headphone amplifier.


Type: Over ear, open
Usage: Home
Driver type: dynamic
Pads: replaceable, velour with memory foam.
Inner pad dimensions: height: 60mm, width: 50 mm, depth: rear=25mm/front=20mm.
Foldable: No
Headphone connector: 3.5mm TRS
Cable entry: single sided (left)
Cable: 3.0m cloth covered 3.5mm TRS + 6.3mm adapter
Driver size: 50mm angled
Power rating: 0.5W (500mW)
Max. Voltage: 3.8V
Max current: 125mA
Max. S.P.L.  117 dB
Impedance: 30 Ω
Efficiency: 100 dB @ 1mW
Sensitivity: 115dB @ 1V
Weight: 380 g. , cable adds 60 g.
Clamping force: high
Colour: black
Accessories: Cable clamp, 6.3mm adapter.

Sound description:

The short description is excellent. It doesn’t have any obvious faults when it comes to sound
Bass is deep, not overblown but maybe a tad ‘rubbery/boomy’ with some music would if I were nitpicking.
Transition from bass to the mids is smooth and accurate.
The mids are clear, open, accurate, dynamic.
Treble too is excellent, no sharpness, no sibilance, no coarse treble, not splashy, not ethereal. It sounds accurate and well defined.
This is one of the few headphones that does not need any EQ and sounds excellent as it is.
Sounds better than its price point suggests and proves brands like Philips which are not considered your typical headphone brand can build excellent sounding headphones below the €300.- price point (street price).


Below the frequency response of the X2HR (Left, Right)FR
The 3rd one I measured did not have channel imbalance. The other 2 that were measured did have channel imbalance (shown further down below)
From 30Hz to 2kHz the response is exemplary. The small dip around 3kHz is not as deep because the drivers are angled and make use of Concha gain.
Up to 13kHz the response is flat. Around 14kHz the response drops below -3dB.
From 13kHz to at least 30kHz the response is still there but at a lower level.
This makes the HR behind the X2 a bit suspect.

hi-res logo

There is a Hi-Res logo on the box which I have seen on a lot of  headphone boxes. I am starting to wonder what this actually says of the performance. (Note this is a general rant and not specifically related to this particular headphone)
Philips states the frequency range is 5Hz to 40kHz.
Usually in electronic equipment this is specified within 3dB or +/-dB. Sometimes even within 0.5dB.
With headphones this is not the case. Not in the least because there is no consensus as to how to measure and compensate.
Below the frequency responsebut smoothed. It appears that Philips (and almost all other manufacturers) simply use the -20dB limit to specify the bandwidth. Does such deserve the hi-res logo ?
FR smoothed
If we were more honest and would define the frequency response at -3dB then the X2R would still have a respectable frequency response of 25Hz to 16kHz which is about the total frequency response an adult can actually hear. This means everything from the lowest bass notes to cymbals is heard at the correct level.
Indeed it does not sound rolled-off in the lows nor the treble.

It should be noted though that the X2HR sounds remarkably clean, clear, open and hi-res with excellent treble. So when it comes to sound quality this headphone definitely sounds high-resolution. Those expecting to get full benefit of the extended frequency response of say DSDx4 or 192kHz or higher bit-rates they would have to realize that the headphone rolls-off quickly above 14kHz.

I ordered one for myself. Hoping it had better L-R matching. Below the sobering results of the measurements (Left, Right) so it was returned.
2e X2HR unbalance
The version below was the first one I measured and had some L-R imbalance below 100Hz. It wasn’t very audible. The measurement above was audible.FR X2HRIt looks like Philips has quality control issues. A 3dB difference is audible. Have taken multiple measurements in various positions and checked and double checked.
The differences are really there. Also distortion measurements came out different as can be seen further below.

compared to

As most people are interested to see how it compares to other headphones that are considered ‘realistic’ sounding below a couple of plots with well known headphones.

Below the Fidelio X2HR versus the Fidelio X1X1 vs X2
Bass response and mids up to 1kHz is very similar. The X2HR, however, has much more clarity (presence between 1kHz and 6kHz) and the treble is a bit more elevated.
Note: the upper frequency of the plot is 22kHz.

Below the Fidelio X2HR versus the Sennheiser HD600HD600 vs X2HR
Bass extension of the X2HR is better than the HD600. From 100Hz to 2kHz both headphones are equally neutral. Above 2kHz the HD600 is somewhat better. Treble of the X2HR is slightly higher but less extended. But overall it shows the X2HR is remarkably ‘neutral’.
Note: the upper frequency of the plot is 22kHz.

Below the Fidelio X2HR versus the Sennheiser HD650 (2018)HD650 vs X2HR
The X2HR doesn’t have the ‘midbass warmth’ of the HD650 and is more neutral in this aspect. The X2HR also is better extended in the lows. Above 2kHz the same applies as for the HD600. The upper frequency extension of the HD650 is better.
Note: the upper frequency of the plot is 30kHz.

Below the Fidelio X2HR versus the  Sennheiser HD660SHD660S vs X2HR
Bass extension is better on the X2 and the upper treble is higher than that of the HD660S
Both the HD660S and X2HR have a similar ‘dip’ around 3kHz (which in reality is not really audible as such)
Note: the upper frequency of the plot is 30kHz.

Below the Fidelio X2HR versus the Beyerdynamic DT880DT880 vs X2HR
Here we see the obvious bass roll-off heard in the DT880 is not present in the X2HR. On the contrary, the X2HR is even very slightly elevated. The treble level of the DT880 is higher though. Those that found the Sennheisers lacking in treble and the DT880 way too hot in the treble and like a bit more bass extension but don’t want to trade in realistic mids should really consider the X2HR.
Note: the upper frequency of the plot is 30kHz.

Below the Fidelio X2HR versus the HIFIMAN HE6 (4-screw)HE6 vs X2HRLower bass of the X2R is a bit higher than the HE6. Bass extension of the HE-6 is much better. Treble extension of the HE-6 goes beyond 30kHz, the Philips to 16kHz.
Of course distortion levels of the HE-6 are much, much better but in tonal balance both headphones can be considered as neutral/realistic.
Note: the upper frequency of the plot is 30kHz.

Below the Fidelio X2HR versus the (closed) audio-technica ATH-MSR7ATH MSR7 vs X2HR
Bass extension of this closed headphone is on par with the open X2HR. The ATH-MSR7 has an audible hump around 200Hz. The X2HR is better in this aspect. Both headphones carry the hi-res logo but roll-off before the headphones above. The X2HR is slightly better sounding as in more natural.
Note: the upper frequency of the plot is 30kHz.


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 (temple) pair of glasses, seal broken using a 6.3mm TRS plug.sealA perfect seal clearly is not needed. Using glasses won’t affect the LF response of this headphone.

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 13.0dB 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. 120 Ohm -13.0dB
This headphone does react to a higher output resistance by increasing the bass. As this is lower bass only the sound doesn’t become muddy/bloated but more bassy. Maybe a bit too much.
What is clearly visible is that the bass increase is obviously caused by the resonance of the driver.
Because of this it is pretty safe to conclude that the difference in bass roll-off is due to the driver being differently damped. As this is an open headphone it isn’t an enclosure issue but a driver issue.

Another clue that something is up with the right driver is found in the distortion measurements of the X2HR.
Below the Right channel (the left channel was slightly better measuring).Dist RThe plot above is in a dB scale, below the same measurement but in a percentage scale.Dist R percentThe distortion level is decent at 90dB SPL. Better headphones have distortion below 1% in the lows.
Above 90Hz distortion is below 1% and drops to good levels above 100Hz.
NOTE: The actual 2nd harmonic distortion above 300Hz may well be lower than 0.2%. A shortcoming (measurement limit) of my measurement rig.

Time domain measurements

Below the CSD of the X2HR (Left and Right are superimposed)A resonance is seen at 5.5kHz (also visible in the distortion plot). I don’t think this has any audible consequences.

Another form of looking in the time domain is the spectrum plot. The amplitude is color coded and both the time scale and frequency scale differ as well.

Below the spectrum plot of the X2HR (Left channel) spectr L
This plot looks quite good. There are no obvious, long lived resonances visible. A short one at 5.5kHz but otherwise this driver looks well damped. The stuff around 1.5kHz is ambient noise as this is a quite open headphone.

Below the step response with a dB scale (so not similar to an oscilloscope plot which has a linear scale).  The step response (Left and Right channel overlayed) Step X2HR
The bass extension is decent but lacking compared to quite a few other headphones.
The rising edge reaches -1dB and is equally high as the mids (300μs to 1ms) which means the attack and tonal balance is excellent. The ringing is small and very short lived.
The small resonance around 5.5kHz remains present (and visible) to almost 5ms.

Square-wave and impulse response

Below the 40Hz and 440Hz square-wave response as well as a 100μs DC impulse.
SQRThis is for the Left channel only.
The 40Hz square-wave shows there is roll-off in the lower frequencies but not severe.
The 440Hz squarewave is excellent and almost exemplary. A near perfect square wave indicates excellent and realistic mids. The ringing is short lived and low in amplitude.
The measured signal closely follows the applied signal.
The impulse shows excellent impulse response. The measured signal reaches the target level indicating excellent impulse response. In the horizontal part the 5.5kHz resonance is visible.


After playing it for a while I found the bass a bit too strong and ‘wooly’ and wanted the treble to be slightly lower but the treble extension should not be affected.
Already had an idea how to lower the bass hump by increasing the damping of the driver itself. Having seen pictures of the driver on the web I noticed the hole in the damping paper ring was a bit large.
The baffles with drivers are easy to remove. Just pull of the drivers and remove the 4 screws. Below a picture of the rear side of the X2HR driver. The hole in the paper ring around the driver is seen in the red circle.

driverSome experiments were made to determine the effect of sealing the hole in steps.
stock (hole fully open), hole sealed 50%, hole sealed 75% (25% open), hole fully sealed.X2HR holes experiment
This experiment showed that my desired response is somewhere between 50% and 75% so ended up with sealing off about 2/3 of the hole.
Those that like the amount of bass should not perform this mod. The advantage of this modification is that one can tune the bass response by ear by taping the hole partially.
If you feel more lows need to be removed, make the hole smaller. It also easy to reverse this modification.

Only the treble response needed to be lowered just a tiny bit. About 2 to 3dB above 1kHz should do the trick. This is not easy to realize using acoustical adjustments as more often than not this mostly affects > 10kHz too much and one looses the air. Given this driver already drops off above 14kHz this meant using electronic components for filtering.
Of course the lows could also be filtered but want the bass not only lowered but also damped a bit better.

The filter consists of 3 components: 1mH inductor, 1μF capacitor and 18Ω resistor all in parallel and this soldered in series with the driver. Below the filter itself.
If you are interested in an external filter this can be made on request. Only only needs to tape off the hole in that case.
filterBelow the driver with the filter fitted (it looks like it is in parallel to the driver but it is not the case. The filter is pointing upwards so they are not soldered together.
The hole was partially taped off with a small piece of duct tape so that 1/3 of the hole remains open. (see green circle)modif

Below the difference between the stock X2HR and modified as shown above.mod vs stock R
As can be seen bass extension is not affected but the small, but audible, hump around 60Hz is gone. Also the treble level is lowered but not above 10kHz.

When both channels are modified the frequency response is as shown below (Left, Right)X2HR modified
Bass quality is improved while the deep bass is still there. Treble is at the proper level.
To me the changes are subtle but make me enjoy the headphone more.
Bass remains a bit ‘rubbery’ and still lacks definition. Not as tight as I want it to be.
Later I closed the hole a bit further (now 25% open and 75% closed)

Distortion changed as well of course, More damping means less 2nd harmonics and increased 3rd harmonics.
Dist percent modif R

Below the CSD of the modified X2HR (Right and Left superimposed)CSD modif.png


The Philips Fidelio X2HR is an excellent, realistic and neutral sounding headphone.
For the going prices between €160.- and €240.- this is a headphone with a very high VFM (Value For Money).
The sound quality, build quality and looks are very good and pricing is competitive.
It is an open headphone so not really suited for portable usage. The fact that it has a long cable and is not foldable also rules out it is intended for outdoor portable usage.
As the headphone is quite open it also isn’t very useful for office usage when one wants to drown out noise or not bother collegues.
What it is perfectly suited for is listening indoors via desktop equipment but also directly from a phone (with 3,5mm TRS socket), tablet, laptop or DAP.
A shorter cable is recommended in that case.

Downsides would be the rather high-ish clamping force (out of the box) but with a little bending of the headband this can be lowered quite easily , the microphonic, long, stiff cable and the slight wooliness in the lows.
The difference between L and R driver driver matching is an issue and shows Philips does not perform any post production measurements or quality control. Most likely they just mount some drivers coming from an assembly line without taking an effort to match drivers. So whether you have a good or lesser one may be a lottery ticket. In one case the L-R differences were audible.
The cable can easily be replaced.
While the pads are replaceable Philips does not seem to sell these which is a bit strange.

Modifications as shown above make the bass a bit tighter (but still retains a somewhat rubbery character) and is less prominent.
The filter modification makes the treble ‘smoother’.
I really like the sound of the modified X2HR.

post separation

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  1. Carlos says:

    Congratulations! I love your reviews and mesurements.

    I own the Fidelio X2HR. Can you recommend an eq profile to make the frecuency response more similar to the Sennheiser HD 650 above 2khz ?

    Greetings from Spain! Thanks!

    • Solderdude says:

      I don’t use any EQ profiles. You could compare plots of the X2HR with those of the HD650 (overlay them) and use equalizer bands to compensate the differences for those bands.
      You can ‘tweak’ from there.

  2. audiothinker says:

    It would have been interesting to have a vs HD599SE curve (they were both available on sale at 100€ recently and I’m debating which one to return).

    I’m having a hard time identifying the differences. The bass on the X2 does seem boomier though (IMO) less deep. I’m also getting some indications of siblance in the top end.

  3. audiothinker says:

    BTW, awesome site, thanks for making all this info available!

  4. maxmot says:

    Hello, for the filter, I have some doubt on condenser… what type of condenser you have used ?
    The condenser in photo is very small for have an value of 1μF…

  5. Patrick says:

    Hi, for the series connection of the high frequency filter on the driver, I should solder both cable together on either the positive or negative side of the driver, correct? Because from your picture it seems wired that way, thanks.

    • Solderdude says:

      The picture is a bit misleading (missing 3D information)
      Just unsolder one of the wires to the driver and solder the filters between the, now open, solder pad of the driver (where the wire came from) and the wire on the other side of the filter.
      The filter thus goes in series with the driver.

      • Patrick says:

        Hi Solderdude, thanks for the clarification. Just curious, what happens if I connect the filter in parallel? Does it work the same as in series?

    • Garygarlucia Luciani says:

      Love your sight and headphone reviews

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