Fit and Comfort

I am not going to say the Fidelio X3 is the most comfortable set of headphones out there, but gosh darn if it does not feel like it! Once broken in properly with the support band not yearning to lift it off your head, it comes really close to my personal gold standard, which is the Sennheiser HD598. That offering from Sennheiser, incidentally, is significantly smaller and lighter, and the stock velour pads are near-perfect for me. What Philips did here, especially compared to the Fidelio X2HR, is make things smaller and lighter, which helps. The material choices by themselves don't do much for comfort, but do help with the fit, especially with the large, deep ear pads that can accommodate pretty much everyone's head and ears. My own average head with averagely sized and shaped ears went in swimmingly, and the foam pads with the support band provide enough clamping force to keep the Fidelio X3 in place easily.

Cable management is a different aspect, however, since you may be tempted to take these on the go. Just be aware that the leather and fabric require more thinking when outside in less-than-ideal conditions, but what exactly are you going to do with the 10-foot long cables? Get shorter cables, maybe even with a softer or rubber sleeving, and make sure the connector is what you want depending on whether you are driving the Fidelio X3 in balanced mode or not. I suspect Philips mostly intends this offering to be a desk queen, however, and that is pretty much how I used it too. Did I also mention often enough how this is an open-back headphone that will absolutely let a noisy environment in?

Audio Performance

Audio Hardware

I have had so many ubiquitous 40 mm headphone drivers recently, and there are a couple more coming up too, so the 50 mm dynamic drivers here might as well be a revelation. Not a lot is different from the X2HR driver system, but there is enough to talk about. With a rated impedance of just 30 Ω, driving the two 50 mm neodymium drivers is extremely easy; no aftermarket amplifier is required. DACs will always go a decent way in the audio experience, however, and the option of a balanced sound input does mean more specialized gear than your average music source. Philips also rates the signal sensitivity at 100 dB and cites a frequency response of 20 Hz to 40 kHz, but good luck making use of that range! It does get the company the Hi-Res audio badge, however.

The entire package around the drivers is what contributes to the sound signature, and there is a decent amount to discuss here. For example, the Fidelio X3 uses a similar double-layer enclosure to minimize harmonic vibrations, but Philips says the enclosure has "new strengthening ridges designed to stiffen the enclosure and minimize resonance." Look above at the drivers on the X2HR with 40 ridges; these have been reduced to 20 on the X3. The drivers themselves are angled inwards 15° to better match the ear canal, and Philips also states that the driver enclosure with three layers includes damping gel between two polymer layers, with the thickness of each layer also changed for fine adjustments to the stiffness of the diaphragm across the entire frequency response while retaining decent bass output. These customized layers and the ridge design are supposed to make for satisfying lows followed by a more progressive drop off in the mids and highs (frequencies).

Audio Quality

I will preface this section by mentioning that my general preference is for a V-shaped sound signature emphasizing elevated bass and treble with a recessed midrange. I also generally prefer instrumental music over vocals, which complements the V-shaped profile. Unlike IEMs, I do have a good deal of headphone experience in different price ranges, including other headphones in the same price range as the Fidelio X3. That having been said, I was in two minds about whether I should wait until after I get in a set of tools to generate frequency response curves for some headphones and IEMs. However, the Fidelio X3 has been on the back-burner for a while even after the break-in period to where it would have been another couple of months at least for what is ultimately a loaner item. I do appreciate Philips USA working with the UK team on having me hold onto these for longer than usual, which, as previously mentioned, came in handy for multiple reasons.


The main reason outside of break-in is because of the multiple source modes. I ended up spending a month between the two with different sources to see how they out. Above, we just saw all the design parameters directly from the horse's mouth, which Philips says make the Fidelio X3 sound like a "concert hall for your ears." Such a description typically refers to the soundstage, which I expect to be wide and open with open-back headphones. I was not sure what to expect going in, with the fabric over the ear cups impacting ventilation and heat dissipation negatively slightly compared to even the Fidelio X2HR. The fabric, as it turns out, is not only transparent to auditory signals but also part of the design Philips' sound engineers worked with. If anything, the Fidelio X3 sounds even wider to me than the Fidelio X2HR and Audio-Technica ATH-AD900X, and about on par with the beyerdynamic DT-990 Pro I personally think has an absolutely ridiculous soundstage in this price range. There are a few offerings from Sennheiser that come close or even surpass the Fidelio X3, including less expensive options, such as the Massdrop HD600x, but the so-called Sennheiser veil does come into play if you know what I am talking about.

Philips made sound separation a big deal in their marketing, with balanced mode only just behind it. With the typical 3.5 mm unbalanced option, things will not be that different from others using a single cable and output mode. But balanced mode makes the most sense here should your source allow it as the whole system seems to have been built around it. It allows for the cancellation of noise picked up on the way to the headphones, and if you have used it before, it does work out as expected. If not, you are in for a surprise provided it is backed by an appropriate source. There is of course fantastic channel separation as expected, so much so that it can make for a decent set of gaming headphones, too. You are not going to approach IEMs for sound isolation and separation, especially balanced armature units, but the Fidelio X3 does a commendable job. Most of my headphones are unbalanced, so there's not much to compare to here.

From FiiO to Creative to Topping, I did try the Fidelio X3 with a couple of different DACs to see if it benefits from different grades of sources. No need for any pre-amps or a dedicated power supply here, but I will say that a halfway decent DAC will go a good way in enhancing your experience. But those wanting to pick this up without worrying too much about the source should not be discouraged. In practice, the actual fidelity of files played will matter more anyway. What is more important to know, however, is that it does not sound anything like the Fidelio X2HR.

Okay, maybe nothing alike is a touch too strong a statement. But those discerning between the two will notice it. If you have both on hand, it is all the more clear that the Fidelio X3 was tuned quite differently, to where fans of the older X2/X2HR may not like it at all. The older headphones had a lot of energy with pretty good bass and warm tones throughout. This one, on the other hand, is meant to be more neutral. This is not to say that the Fidelio X3 falls into the monitoring category since there is still some appreciable change in the mids. While the somewhat decent bass from the Fidelio X2 is present, bass isn't nearly as present as on most of the other open-back headphones mentioned above, certainly not in comparison to your average closed-back thumping set of cans. Even going in knowing it somewhat, it is the treble range I found most surprising. Things are slightly muddy with string instruments before break-in, but get better somewhat afterwards. To me, female vocals coming off the mids and moving into the highs are affected more, especially since the vocals in the mids sound fantastic. In a sense, Philips built the Fidelio X3 to be pretty much counter to my specific preference. I can't blame the product for it, but as a potential customer, you do need to be aware of it. These are best for those prioritizing music, preferably from a high-quality output and source to begin with (say, Tidal or local FLAC files) with an emphasis on vocals and the mid to high frequency range. Not necessarily the most neutral out there!