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Philips Fidelio S2

Philips Fidelio S2 In-Ear Earphone Review

Philips Fidelio S2

Brief: Flagship earphone in Philips’ sound-focused Fidelio line
MSRP: $149.99 (manufacturer’s page)
Current Price: $100 from$125 from
Specs: Driver: Dynamic | Imp: 22Ω | Sens: 107 dB | Freq: 15-24k Hz | Cable: 3.9′ L-plug w/mic & 1-button remote
Nozzle Size: 5mm | Preferred tips: Comply T/Ts200, Stock single-flanges
Wear Style: Straight down

Accessories (4/5) – Single-flange silicone tips (5 sizes), Comply S200 (1 pair) and Ts200 (1 pair) memory foam tips, and zippered clamshell carrying case
Build Quality (4/5) – The construction of the Fidelio S2 is similar to the S1 model, but – in contrast to the partly-plastic S2 – is all-metal and boasts a fancy-looking glossy finish reminiscent of ceramic earphones such as Sennheiser’s  IE 800. The earphone utilizes textured flat cables with an in-line microphone and single-button remote
Isolation (3/5) – Average, not as bad as could be expected from a shallow-fit design
Microphonics (4.5/5) – Good
Comfort (3.5/5) – The Fidelio S1 and S2 are built around 13.5mm dynamic drivers – large for IEMs, but definitely not unheard of. Philips chose a half in-ear form factor for the earphones, placing the driver enclosure in the outer ear with an angled nozzle fitting into the ear canal. This sacrifices some noise isolation for the comfort of a shallow seal, but the wide housings fitting 13.5mm drivers put a lower limit on the size of ears that will tolerate these earphones – smaller ears just won’t fit the housings comfortably

Sound (9/10) – Philips did a spectacularly good job with the tuning of their new high-end Fidelio line, both the two in-ears and the on/over-ear models I tried at the 2015 CES. The Philips Fidelio S1 and S2 in-ears sound clear and accurate with just the right amount of bass kick. The low end extends nicely, with mild overall boost and impact reminiscent of the VSonic GR07, an IEM highly renowned in audiophile circles.

The mids are crystal clear, with resolution to rival accuracy-oriented in-ears from VSonic and HiFiMan. The lack of bloat helps, allowing the deep bass of the Fidelio S2 to shine and keeping the midrange completely clear of bass bleed. Treble presence is good too – the earphones aren’t lacking at the top end for my tastes, and I’ve been known to enjoy a more energetic sound. At the same time, the treble is free of grain and harshness, but there’s a bit of a lift in the upper midrange and lower treble area. In comparison, the VSonic GR07 sounds a little peaky and sibilant at the top end, while the HiFiMan RE-400 is smoother and more laid-back.

The presentation boasts good width with average depth, reminding me of a slightly more mid-focused and less broad-sounding VSonic GR07. Curiously, the Fidelio earphones are not super efficient for a portable audio product and take more power to reach listening volume than much of the competition. This isn’t a problem except for those who gauge sound quality by maximum attainable volume – there’s still plenty of headroom with portable players. The earphones aren’t picky with sources, either, and sound decent enough from a sub-par Android phone.

There is one small caveat with the both the S1 and S2: they require a very good acoustic seal to perform their best. This is true for almost all IEMs but because of the shallow fit and near-neutral tuning of the Fidelios, there’s not much room for error. The large size of the housings and limited insertion depth play a factor as well. Without a good seal the bass quantity drops, the treble sounds a touch hot and spitty, and the presentation loses its depth. Here, the pricier S2 model has an advantage of the S1 with its extra eartip sizes and Comply Ts-series foam tips.

Select Comparisons

Philips Fidelio S1 ($100)

The Philips Fidelio S1 and S2 really don’t differ much, especially when it comes to sound. In addition to its better build quality and fit kit, the pricier S2 model has a slightly more full-bodied sound with a touch more bass. Both can sound a little hot in the treble, especially without an optimal seal, but the S2 is a touch smoother with stock tips. At the same time, it maintains a marginally more airy sound than the lower-end model.

HiFiMan RE-400 ($79)

One of the pioneers of accurate-sounding dynamic-driver earphones, HiFiMan have been selling earphones in this segment since 2008 or so. Compared to the Fidelio S2, their latest $100 offering, the HiFiMan RE-400, is more efficient, warmer in tone, and boasts more intimate mids and a more in-the-head presentation overall.

The Fidelio S2 has more subbass & bass in general but is also less warm and a touch clearer as a result. The mids on the S2 are less forward but it has a boost in the upper midrange/lower treble and sounds brighter on the whole. The RE-400 is smoother and more laid-back up top, sounding more refined and forgiving. The Fidelio S2 is more spacious and has a wider soundstage but gives up the intimate feel and more well-rounded presentation (in terms of depth and width being more even) of the RE-400.

VSonic GR07 Classic ($99)

VSonic’s similarly-priced, accurate-sounding dynamic-driver IEM is a direct competitor for the Fidelio S2. The GR07 is more sensitive than the Fidelio S2 but otherwise they don’t sound very different, either. The two have similar bass quantity, but the S2 has a flatter/more linear low end while the GR07 has a bit more of a mid-bass hump. As a result, the VSonic unit boasts a hair more bass impact, slightly warmer tone, and a more full-bodied sound while the Fidelio S2 sounds a touch thinner and has a cooler tonal character.

Despite being less warm than the GR07 and having some upper midrange lift, the S2 tends to sound smoother than the GR07 and is less prone to sibilance. The VSonic unit does have a slightly more spacious and three-dimensional presentation, but, thanks in large part to the sibilance, I don’t feel that it is superior to the Philips overall.

RHA MA750 ($120)

Compared to RHA’s warm and bassy MA750, the Fidelio S2 is much more neutral, clearer, and more transparent, but also a little harsher in the treble region. The MA750 sounds thicker overall and suffers from more bass bloat. It is definitely smoother than the Philips, but the top end can still be a little tizzy, especially at high volumes, and the deeper v-shape of its sound signature is audible.

RBH EP1 ($149)

The EP1 is notable for having a very similar form factor to the Fidelio S2, as well as similar build and accessories. The sound of the EP1 is bassier, with the enhancement most audible in the mid-bass region. Its mids are more forward and can appear a little clearer as a result, though on the whole the Fidelio S2 has similar clarity. The RBH unit is also a little harsher, can appear less natural in tone, and its presentation is a little more congested. The more balanced and neutral S2 – despite its slightly more recessed mids – sounds more realistic.

Dunu DN-1000 ($200)

The Fidelio S2 is a dynamic-driver earphone with accuracy-oriented tuning. The DN-1000, which boasts a v-shaped sound signature, has much more of a “wow” factor to its acoustics. Its powerful bass easily outpaces the Philips set, which itself is no slouch when it comes to depth and impact. More surprisingly, the Dunu seems a bit clearer than the more balanced-sounding Philips, due in part to its brighter tonal character. The Fidelio S2 is not the most exciting earphone in the first place, and next to the DN-1000 it sounds especially dull. On the downside, the treble of the DN-1000 has a more “metallic” timbre than that of the Fidelio S2, especially at higher volumes, which is not uncommon for earphones based on the Knowles TWFK driver. The Fidelio S2 is also significantly less efficient than the DN-1000.

Noble 4S ($999)

Compared to the Fidelio S2, the Noble 4S clearer and more balanced, but also a little thinner. The S2 has more bass emphasis and sounds a more full-bodied as a result. It lacks some of the clarity of the 4S, though, and gets harsh a lot more easily. The 4S, despite having a similarly healthy amount of treble energy, is smoother, especially at higher volumes. Lastly, the 4S sounds more airy and open and has better soundstage depth and layering while the S2 is more closed-in.

The Headphone List Recommended EarphoneValue (9/10) – Philips is not the first brand that comes to mind when I think “headphone Hi-Fi,” but the Dutch electronics giant has been designing and manufacturing headphones since the 1960s – longer than many of its current competitors have been in business. The 2012 introduction of the Fidelio line of performance-oriented audio products, with its aggressive pricing and solid audio quality, makes it clear that the company is still serious the about high-end personal audio market.

The Philips Fidelio S2 is a well-designed, user-friendly earphone boasting a neutral sound signature with a bump across the bass range, tangle-resistant cabling, and a built-in microphone and remote. The semi-open design makes them great in situations where the higher noise isolation of most other high-end earphones is undesirable—and a great choice for those who don’t like the more intrusive fit of most other IEMs. For a flagship product, they are also quite reasonably priced, costing less than the flagship IEM from any of the other major manufacturers.

Pros: Shallow-fit design; balanced and very capable sound
Cons: Mediocre isolation; housings on the large side



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Living in the fast-paced city of Los Angeles, ljokerl has been using portable audio gear to deal with lengthy commutes for the better part of a decade. He spends much of his time listening to music and occasionally writes portable audio reviews across several enthusiast sites, focusing mostly on in-ear earphones.


29 Responses

  1. I got these S2s a while ago at Bought the pale blue simply because they were £40 as opposed to £110 for the black.
    Don’t care that they look a bit dodge, sound great.
    Fit is crucial though and I’m using some Spinfits which came with my Trinity Audio Icarus IIIs.

  2. I wish I could try this earphone in real. I would buy it in an instant if it fit well. These look huge. Do these fit like earbuds? They look the size of an earbud.

  3. Hey |joker|, hope you’re doing okay! This is long overdue, but I would just like to write a reply to thank you, and hopefully help others who are in the same situation as I was.

    The DUNU Titan 1 is absolutely insane. Like freaking insane. It absolutely blows the S2 and the HF5 out of the water in terms of details on the higher end; I can hear and separate things like cymbals and shakers very clearly now, and trumpets have that kind of peak to them that’s just right (not sibilant, yet not smoothened either).

    So yea I just wanted to reply because I’m very grateful to you for recommending this pair of earphones. Once again, thank you so much!

  4. Yes, HF5 should be sufficient for this. The S2 is not very aggressive with detailing and provides more of a smooth and coherent sound than your typical (analytical) BA sound, a-la HF5.

  5. Wow, it actually sounds like Titan 1 outclasses the HF5.. Hmm..

    But anyway, I still think I’ll spring for the HF5. I can only find a Fiio Ex1 2nd gen around my area, and I can’t find any reviews on whether they are similar to the Titan 1. Even though it is a sidegrade to the S2, do you think the HF5 is brighter (crisper details and vocals)? What about instrument separation?

    Thank you!

  6. HF5 is flatter throughout whereas Titan 1 has a more sculpted/colored sound. It has a sizable upper midrange boost, so lower mids seem a bit more subdued than they are on HF5 and female vocals are boosted. Overall tone is brighter compared to the more neutral HF5. Soundstage is wider and more airy, but perhaps a bit less precise in terms of positioning.

  7. Hi |joker|, thank you for your reply! Other than the bass quantity, how would you compare the Titan 1 and the HF5? (like their mids and highs)

    Thank you!

  8. Hi |joker|, I would like to seek your opinion again! I’m really enjoying my S2, and I really liked that little bit of bass boost this earpiece, even though it makes the S2 not a strictly balanced earpiece. However, I still find myself craving for a little bit more clarity in the vocals. I’m not really sure how to express this, it’s like sometimes I would prefer a louder and sharper/colder voice over a lusher, mellow sound (which often feels like it’s at a low volume).

    Would the HF5 be good for articulating details like that? However, I do understand from your HF5 review that they are lacking in the bass department as compared to the S2. Alternatively, do you have any other recommendations? Thank you so much!

  9. They’re not too far apart in terms of sound quality. S2 is going to have a little more bass impact and more upper midrange presence , which gives it a little more “bite” with guitars, for instance. IM02 is going to be flatter overall with a marginally darker tone. If accuracy is the goal I’d give the nod to the IM02.

  10. Hi ljokerl, I would like to seek your opinions of and comparison between the Fidelio S2 and the ATH-IM02, and what your recommendation would be!

    Thank you so much!

  11. Hey ljokerl, would like to hear your opinion on the difference between the Fidelio S2 and the ATH-IM02, and your recommendation!

    Thank you!

  12. While and gold (if I remember the color scheme correctly) isn’t the most masculine combo, but that would be a hard deal to pass up.

  13. The s2 white ones are $60 refurb are they worth it or should i go with the hf5

    PS. The white s2 looks really girlish lol some reason but for $60 idk if i can turn down the deal

  14. It’ll mostly come down to the type of sound you want as those are all very capable IEMs (except maybe the Pioneers, never tried that model but I have yet to be impressed by one of their IEMs). For example if you like enhanced/impactful bass you can forget about the Flux Pro. If you’re very sensitive to harsher upper mids the Fidelio S2 may not be as good a choice as the others listed. And so forth.

    For me, barring any specific sound requirements, it would probably be down to the MA750 vs Fidelio S2 depending on whether you’d rather have a more heavy-duty build, extra bass, and an over-the-ear fit (MA750) or a more shallow, earbud-style fit with more neutral/balanced sound.

    With those prices the SE215 isn’t worth it unless you have to have detachable cables. Here in the US the MA750i is about $30 more expensive than the SE215 and I still think it’s a better value. In your cases the price situation is reversed so I’d always pick the MA750i over the SE215. Paying $50 more for the EPH-100 over the MA750i is difficult to justify as well, barring any specific sound requirements that would make the EPH-100 a better choice.

  15. I compared them to the RE-400s at length in the comparisons section of the review above… Don’t really have anything to add to that.

    The Fidelio does have more bass and marginally better clarity, but the only time there’s more detail resolution is when the brighter upper mid/treble region comes into play. I don’t think it’s enough of a step up in that regard. The mids are also no more forward on the Fidelio S2 than they are on the RE-400. If you want more aggressively clear and detailed mids in this price range, I’d recommend the DUNU Titan 1: . There’s also a comparison that a new Titan 1 owner posted coming from the RE-400 in the comments section of the RE-400 review:

  16. hi, many thanks for all your hard work. i’m looking for a nice pair of iem with a price tag of around ~100-150€.
    Genres I listen to are: swing, electro swing, jazz.
    most important aspects for me are: comfort, sound quality, value.
    i can’t decide between these models (in brackets local prices of my country, i don’t live in the US; i converted the prices to US $):
    – Philips Fidelio S2 (130$)
    – RHA MA 750i (96$)
    – Yamaha EPH-100 (147$)
    – Pioneer DJE 1500K (100$) (didn’t found much information about these, so i’m not really sure. But i do like fun bass).

    and maybe (i’d buy these because of form factor, but only if they provide a good sound as well)…
    – Shure SE215 (111$)
    – SteelSeries Flux In-Ear Pro (91$)

    what earphone would you recommend me? thanks

  17. In terms of something like HFM re400s which have a great amount of clarity, especially in the mids… how do these compare? i.e. Are the f2 clearer. i love resolution, hearing everything crystal clear. The H4s are superb for this, but I’m looking for something a step up in quality that brings out more of the ‘little things’ in songs that are normally not heard… with a touch more bass but not a deal breaker. The h4s also have a cable that gives of an ungodly amount of noise while wearing them on the go, very distracting. I’d be willing to go up to double the price of H4s.

  18. For me, M tips leak while ML is a bit large, and I feel Philips tips is hard on material so I don’t feel ML is comfortable.
    But luckily, Sony hybrid ear tips nice with my ear.

  19. I do, but I also strongly believe that it’s the latter effect you described (i.e. what is often called “brain burn-in”).

  20. Hello,
    An unrelated question: Do you burn in earphones at first listening? Does burning in actually improve sound quality listening or it is only people getting accustomed to their earphones sound signature after time?

  21. I’d still do S2 just for the all-metal shells and resulting durability… the S1 doesn’t seem to do as well for long-term use.

  22. Question: With the way the Japanese yen is going the price difference between the S1 and S2 is now quite dramatic (~$60 vs ~$90). Do you think it’s still worthwhile to get the S2 over the S1? Fit kit doesn’t really matter to me as I have many spare tips already.

  23. I’ve got a pair of the S2. If I hold them in place with my fingers just right, they do have a really good sound to them. I’ve tried all the tips that came with them, and some from other IEMs and just cannot get the right fit. Bummer, cause i know they are capable performers.

  24. Depends on what you’re looking for, in terms of both sound tuning and design. The EPH-100 is very low profile, with high isolation, warm, bass-heavy sound with relatively smooth mids and treble. The S2 is fairly large in the ear, designed for a shallow fit and average isolation, can be worn cable-down only and has a headset. Its sound is better in terms of overall balance and accuracy, but it is neither as bassy nor as smooth as an EPH-100. It’s the better reference earphone, also better if you want guitars, vocals, etc at the forefront. Not better if you are after significantly enhanced bass or are sensitive to a boost in the upper midrange/lower treble region.

  25. Greetings Joker, I note that you use the words “hot” and “harsh” occasionally in your review to describe the treble of the S2. I own both the S1 and S2, and the TX1 and TX2 as well. Unfortunately I simply never listen to the S1 or S2, precisely because of that treble problem–which the TX1 and TX2 don’t have. Measurements on Inner Fidelity clearly show the reason–the peak at around 4-5 kHz in the lower treble, where the ear is most sensitive. The TX1 and TX2 don’t have that peak.

    All of these Philips IEMs boast very low distortion and good impulse response across the entire range, and for that reason, even the very low-priced TX1 pairs well with high-end equipment. None of them have much treble extension above 10 kHz, and so don’t sound terribly airy. But I’ve enjoyed many good hours of listening with my TX1.

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