A Big Bottom and a Lively Top: The Philips Fidelio X1 Measurements


Click on graphs image to download .pdf for closer inspection.

Raw frequency response plots show a headphone that's fairly immune from tonal changes in various placements. Compensated response plots show a very well behaved headphone. Frequency response falls off quickly below the primary driver resonance at 70Hz, but remains above the level of the 4kH region at 20Hz. Response between 70Hz and 6kHz has a significant warm tilt, but is the longest straight line on a headphone frequency response plot that I've ever seen. In listening these cans never seemed to be missing anything in that region. Quite extraordinary! The bump at 1kHz was not heard in listening. Response between 10 and 20kHz is a bit lower than I'd like to see.

30 Hz square wave response show the typical curved top due mainly to the hard knee in frequency response at 70Hz and attendant phase shift going through the primary driver resonance. This, coupled with the rise in distortion below 100Hz, is a clear indicator for the somewhat loose sounding low bass response.

300Hz square wave shows a fast rise and single overshoot followed by some ringing, which is also evident in the impulse response. If there's a downfall with these cans it's in the slightly grainy sound that these data might represent. None the less, the very clean initial edge of the X1 probably results in their good imaging qualities. I think DIYers might find this a great headphone to experiment with; if you could rid it of this ringing, I bet they'd be spectacular.

The impedance and phase plot show a nominally 37 Ohm headphone with primary driver resonance at 70Hz. Isolation plot shows an open headphone with little in the way of isolation from outside sounds. With 181mVrms needed to achieve 90dBspl at the ear the X1 will reach reasonable listening levels from portable devices, but they're not really designed for them.

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Impulse's picture

Sweet, thanks for reviewing these! Specially now that it looks like they're finally coming to Amazon...

I'm surprised the stock cable's resistance is really that high, I had actually also tested the V-moda cable (along with a couple others) for someone on the boards who was talking about this but I was still skeptical... I figured either my measurement or his were off, guess not!

It's a minor thing for an enthusiast but it seems like a silly oversight on Philips part, ever run across another relatively sensitive headphone with a cable that has a similarly high resistance?

Wall of Fame huh, definitely gonna have to try them. I'd been looking for a warmer complement to my DT 880, was leaning towards the more neutral Mad Dogs but now I'll probably get both of them in for a listen.

Warm yet spacious without mid range sacrificeX1 sound like it'd be great for gamers (there were a few of us interested in them for that purpose at Head Fi).

Tyll Hertsens's picture

...But yeah, I think these might make great gaming headphones. The imaging seems to be there.

I haven't made a practice of measuring the resistance of cables so I'm not sure what the range really is, but I will start doing it regularly now.

miceblue's picture

...were you using the stock X1 cable, or the V-MODA ones you were recommending?

Tyll Hertsens's picture

Mostly the stock cable, but I did both. It made a bit of difference---not huge, but worthwhile.

georgelai's picture


I am so glad I bought the X1 for USD263 a couple of months ago. Hate the headband though as my head is probably as big as yours, no insult intended. Now I'm thinking of getting the L1 too but I'm a bit worried by the small cups (big head comes with big ear lobes I guess). Tell me, are the L1 cups bigger than the Momentum? Also, would it be an overkill to have both an L1 and an X1?

Tyll Hertsens's picture

The L1 earcups are moderately larger than the Momentum.

The problem, it seems to me, with having both is that they're to similar in use.  The L1 doesn't isolate very well, so they really don't make a good portable headphone. 

If you've got ears too big for the Momentum, I think the Sony MDR-1R is a good portable can.  If you're just looking for a stablemate for the X1 at home, I'd say the HD 600. 

georgelai's picture

Thanks Tyll. What attracted me to the L1 was the fact that it was a bit more portable than the X1. It's also, as you indicated in its review, a gentleman kind of headphone in its looks. Whilst I find the MDR1R nice sounding, I don't like its design. 

I wish headphone manufacturers would learn from clothing manufacturers and give us optional sized earcups in S, M and L for every model. There are many headphones I rule out on account of the cup size, and the fact I don't find on-ears and IEMs comfortable doesn't help.


WolfOx101's picture

I roll with both the X1 and L1.

X1 for home / office use.  L1 for commuting / out and about.

Before purchase of the X1 I did think it would be a bit silly having similar headphones - but contary to my fears I think both are great at their intended use cases.

I had to return a pair of Momentums because of ear cup size, but the L1s are fine (for me of slight larger head / ear size).

kyrian's picture


I'm thinking about buying these but, since I have a big head, I'm concerned about comfort and the size of the head band.

Do you know the maximum recommended head size recommended for these? for example, measuring from lower lobe to lower lobe. In my case is around 45 cm

Are the L1s wider?


Broskies's picture

How do these compare to the Beyerdynamc DT 990, another open basshead headphone?

Tyll Hertsens's picture

I remember the 990 as being uneven sounding. Been a while, but I know I didn't like them.

(Hm. No measurements of them, need to fix that.)

markus's picture

Yes please measure them Tyll!

I bought the 250 ohms premium edition lately. The soundstage amazed me. These are awesome for gaming and movies when using headphone surround encoding like Dolby Headphone or DTS Headphone:X. Never thought this was possible.

But the sound is uneven, yes. Mids are a bit recessed and treble is too pronounciated.

Comfortwise, the Beyerdynamic dt 990  probably beat every other headphone, too.

HiFiGuy528's picture

Tyll, have you tried the Sony MA900?  The bass on them kicks ass.

Tyll Hertsens's picture

I been hearing stuff about it.  I'll put it on the Sony list.  Gotta do the R1 series first so they know I'm on it. 

That series is pretty good, BTW. Not great, but competent performance across the board so far. Not done playing with them though, so you never know what may crop up.

Audioaddict's picture

I thought in gaming headphones the wish list was, soundstage and imaging, with a clear and possibly forward midrange? 

Impulse's picture

Depends what kinda gaming you're doing, if all you care about is competitive online play then you're not gonna get much of am improvement from something like the AT AD700 or Senn HD558/598 regardless of how far up you go...

If you do any single player gaming or you case for some immersion factor (good weight/bass etc) on your online play, then you can spend more for something that gives you that without sacrificing soundstage and imaging... Never been an easy balance, that's part of what made the X1 intriguing to me. If I can get along with the X1 for music I might just replace my DT 880 with them as my daily/desk/gaming headphone...

If not, well, dunno. I've never liked keeping one headphone just for music and one for gaming. I like having two different sounding headphones, just can't have one be exclusively for gaming, feels like a waste (when life gets busy and I don't get to play anything for a month).

TheManko's picture

It's hard to say there's any ideal headphone for games, given how many different kinds of games there are, and every game has a slightly different type of sound, even in the same genre. I tend to prefer a balanced sound for games, as I personally use the LCD-2 or HD 800 for games. But many shooters have a somewhat weak low end, as if they assume the the players will be using basshead headphones. But again that feels like a generalization as the mixing styles are all over the place. Most important would be long term wearing comfort.

georgelai's picture

Hi again,

In your video clip, you mentioned the V Moda cable. Which one? The 1-button, 3-button, or the plain vanilla one? Thanks.


Tyll Hertsens's picture

Any of them will work.  Just depends on what you want for a cable.

cactus_farmer's picture

Hi Tyll,

Great review as always. Since you said that the X1 is an open headphone that can satisfy bassheads - how does its bass compare (in quantity and impact) to another open headphone that is said to satisfy bassheads: the Sennheiser HD650?


Tyll Hertsens's picture

The X1 has more bass, and is a little livelier up top. I think the impact is a bit better on the X1, but it may be just quantity over quality.

GNagus's picture

Hi Tyll, first time caller, long time listener.

From your review I believe I would like these headphones, but if I can't buy new earpads and replace them myself then that would make these a deal-breaker, especially at this price.

My HD580 headphones are from the 90's, but the earpads and headband pad are new.

me1337je's picture

Nice review! (as always)

Was wondering though, how do these compare to the HE-400?

AncientWisdom's picture

I think many people, myself included, are wondering the same thing...

Magick Man's picture

Well, "fat-bottomed cans, they make the headphone world go `round".

ultrabike's picture

"The second problem is that the signal shares a common return through the ground of the cable, and the relatively high resistance of the cable will cause a voltage to develop on the ground channel that will produce some crosstalk between channels."

Thank you very much for this observation! This got me thinking. Assuming the headphone resitance is roughly resisitive, and since P = (I^2)R, the ratio of the power through the ground cable to the power through headphone driver (ground cable crosstalk) might be 10*log10(Rgc/Rh), where Rgc is the ground cable resitance and Rh is the headphone resistance (not a headphone expert here, so this could be non-sense).

Assuming this is correct, for Rh = 37 ohm, and Rgc = 1.8 the resulting crosstalk would be -13.129 dB for this particular case. If Rgc = 0.5, this would be about -18.7 dB. If Rh = 300 ohm, and Rgc = 0.5, this would be about -27.8 dB.

On a positive side, based on this post (http://www.diyaudio.com/forums/headphone-systems/7727-headphone-cable-crosstalk-how-avoid.html#post83732) some cables may run separate ground wires (maybe the HD580/600/650/800...). My HD558 cable is detachable and at the cup it is a 4 wire termination so it might run the grounds separately (not sure) which may mitigate this problem. I think the V-Moda's are also 4 wire termination from the picture (http://v-moda.com/audio-only-cable/)

As far as the headphones, the remind me of Kojaku's SR225i (metal mesh cup back with thick and wide cushions - http://www.innerfidelity.com/content/last-call-diy-cans-heres-latest-nick-ns-killer-grado-sr225i.) From your impressions, and the FR both cans seem to have a similar warm tilt (and lively top), though the Phillips driver seems a bit more smooth and extended in low frequency. Really looking forward to check them out!

georgelai's picture

Hi Tyll,

i followed your video suggestion and bent it to fit my Conehead and now I don't have to resort to cutting out the lower cloth headband. Thanks for the suggestion.



Impulse's picture

You totally forgot to add them to the WoF btw... :p

Jazz Casual's picture

Looks like Philips are right back in the game releasing quality headphones at reasonable price points.

WolfOx101's picture

@ Tyll - thanks for the suggestion on the V-Moda Cable which arrived from the US to the UK yesterday - I have immediatley noticed a noticable "lift" - really pleased with the whole X1 experience now